|the paragon vulcan crucible kilns||or look at polishers and tumblers at electrictumblers.co.uk|
The Paragon Vulcan Mobile kiln is generally used for melting and mixing glasses in a crucible, annealing, casting, and moulding glass, ceramics, porcelain, pottery, and raku, although it has other applications. It's a 1290°C kiln with a digital programmer, in Paragon black, or customised berry, blue, jade, navy, pink, purple, or turquoise. Learn about the Paragon Vulcan kiln on this page.
There's only one version: the Vulcan Mobile: a complete wheel-away kiln with a move-aside crucible cover on a pivot assembly. In the US, it's called the Vulcan ll.
Prices here are transparent: they're for UK-EU voltage, CE marked, CL CSA approved, and TUV tested kilns, and include comprehensive instructions, UK VAT, and free continuing support from a top-tier international distributor.
For prices, trading terms, and secure on-line shopping, use the shop link below the menu bar near the top-right of any page. The order form is on the shop page, after the price list near the bottom.
Kilns that weigh more than 30kg can't be delivered by a regular parcel-service van: they need a tail-lift lorry with a hydraulic pallet trolley. GB-mainland delivery charges are on the shop page. For other locations, call or mail.
|Paragon Vulcan Mobile Crucible Kiln.||Paragon Vulcan Mobile Crucible Kiln.|
|Paragon Vulcan Mobile Crucible Kiln.||Typical Crucible.|
|Paragon Sentry Digital Programmer.||Paragon Sentinel Touch-Screen Digital Controller.|
If you want to look at the Vulcan kiln and don't need to read any general introductions, compare or review the main features, or consider other kilns, click here to jump down the page. The kilns will be listed in ascending order of internal size.
|A GENERAL INTRODUCTION TO THE PARAGON VULCAN KILN||OPTIONAL READING|
The Paragon Vulcan kiln is robust, practical, and versatile and is favoured by glass enthusiasts. It's described in detail below so, although there's a comparative table and photos, I recommend that you set aside some time and read about it.
The Paragon Vulcan ll kiln is a 1290°C, eight-sided, top-opening, floor-standing, firebrick kiln, with cone-fire ramp-hold, Sentry 12-key digital programmer. Choose Paragon black or customised berry, blue, jade, navy, pink, purple, or turquoise. However, customised kilns are made to order, so can't be returned if the colour isn't exactly as in the photos.
It normally has an enhanced Sentry 12-key programmer. Its features include thirty-five free-to-set sequences, each one with up to twenty segments, and automatic control over hardware options: an electric kiln vent, a gas injection system, and a USB computer interface.
Alternatively, you can choose an advanced touch-screen Sentinel Smart Touch. Features include those of the Sentry 12-key and real time displays of voltage and current, a novice mode with prompts, firing sequences presented graphically, and wifi updates: so a functional upgrade not just a design preference.
When the programmer turns the elements off at, for example, 700°C, residual heat will continue to increase the temperature briefly. A small kiln might overshoot to, for example, 715°C before dropping back down. A software modification slows down the heating just before the target temperature, reducing any overshoot and improving the accuracy.
Digital programmers allow you to set up sequences, each one with multiple heating, holding, or cooling segments: so you can choose the heating and cooling rates, target temperatures, and hold times, save the sequences, and re-use them.
Being able to create, edit, and save your own programmes is important because, having experimented and diversified, most people fire materials, or combinations of materials, at different temperatures and for different times than are recommended.
Most kilns, even those designed to run at 1290°C, use K23 bricks. These have excellent insulation and resist thermal shock. However, putting heavy crucibles in and out of a kiln is safer with K25 bricks. They're denser and stronger than K23, although take a little longer to heat up. To offset the time penalty, the firing chamber side walls are built from 114mm thick bricks, and the top and bottom from 76mm thick bricks.
Most kilns use a special-limit nickel-chromium K-type thermocouples. These respond quickly to changes in temperature, resist corrosion, and have an error margin of less than 0.4% instead of the typical 0.8%. However, for continual high-temperature high-precision professional use, the Vulcan uses a platinum-rhodium S-type.
The US-international kilns don't come with a shelf or posts or kiln wash or a crucible so, if you don't need these, you won't have to pay for them. However, I've recommended pro kits because a durable heavy cordierite shelf resists thermal fracture, provides a smooth stable work surface, protects the floor of the kiln's interior from glass accidents, and helps to even out any small temperature deviations during annealing, enamelling, firing, fusing, and heat treating as the elements turn on and off.
For help, or in the unlikely event of a fault, you can mail or call an engineer in the UK. However, checks, adjustments, and repairs are simple, needing little more than a PosiDriv screwdriver: watch the on-line videos using the watch-videos link or read the help pages using use the help link, both below the menu bar near the top of any page. Alternatively, we can service the kiln in our workshop at Cherry Heaven.
Use them for crucible glass work, firing ceramics, earthenware, porcelain, pottery, and stoneware, glass annealing, bisqueware, ceramic art, china painting, applying decals, doll making, fire polishing, glass art, glass fusing, sagging, and slumping, heat treating, laboratory testing, lampwork, lost-wax casting, mixing custom glass colours, pâte de verre, raku, staining glass, hardening and tempering blades, cutters, dies, and tools, and many other materials and processes.
You can make architectural features, bowls, ceramic art, chandeliers, decorations, figurines, glass-art, glass panels, glass stringers, knives, lampshades, mugs, ornaments, plates, stained-glass designs, tableware, tiaras, tiles, tools, and vases, as unique hand-crafted pieces or as repeatable stock for sale.
It's ideal for your arts centre, ceramics studio, college, course venue, craft classes, engineering works, glassworks, knife-making workshop, laboratory, machine shop, metalwork business, school, technical facility, or university.
IS A PARAGON VULCAN KILN THE BEST CHOICE?
The Vulcan ll kiln has been designed for crucible work. However, if you think that a larger, front-opener, or more specialised kiln might be more useful, here are some suggestions:
Bead-annealing kilns generally have a maximum temperature of 650°C, such as the BlueBird Series. However, other kilns have bead doors: the small Caldera-B and SC2B, the medium Xpress-E12B, and the larger Fusion-14B.
Glass kilns generally have a maximum temperature of 925°C. For these, look at the F Series, Fusion:CS Series, GL Series, or Pearl Series. These are not hot enough for ceramics.
Jewellery, silver clay, and enamelling kilns generally have a maximum temperature of 1095°C. For these, look at the small SC Series or the medium Xpress Series. The SC series are not hot enough for ceramics.
Ceramics kilns generally have a maximum temperature of 1290°C. For these, look at the small Caldera Series and FireFly Series, medium Xpress Series, or large Janus Series, PMT Series, and TNF Series. These can also be used for glass work.
Heat-treating kilns generally have a maximum temperature of 1095°C or 1290°C. For these, look at the HT Series and PMT Series. Although they look similar, the HT has a bottom-hinged door and the PMT has a side-hinged door.
Knife-making kilns generally have a maximum temperature of 1290°C. The KM Series are made for depth rather than width. You can choose a guillotine, drop-down, or a side-hinged door.
The W Series have a top vent so are usually used for jewellery moulds and lost-wax burnout. For lost wax casting there are optional metal grids and wax trays. The small SC Series and most of the medium Xpress Series also have top vents.
To learn more about other kilns, use the appropriate links below the menu bar near the top of the page. However, as each series has kilns of different sizes with different options there's only a selection in the table below:
|VERSION||DESCRIPTION||MAX °C||POWER W||WEIGHT KG||FIRING CHAMBER||INTERIOR SIZE MM|
|Vulcan ll Mobile||8-sided top opening||1290||7000||197||firebrick||343 x 381|
|Caldera||top opening||1290||1800||20||firebrick||203 x 203 x 171|
|F-130 Elite||front punty door||925||2400||79||firebrick||279 x 279 x 330|
|Fusion CS-16D||lid and body top opening||925||2400||85||firebrick||406 x 406 x 165|
|GL-22ADTSD||square front opener||1095||11000||152||firebrick||533 x 533 x 337|
|HT-22D||front opening||1095 or 1290||7200||140||firebrick||533 x 533 x 337|
|Janus-1613||top opening||1290||4800||90||firebrick||419 x 337|
|KM-24T||front opening||1290||2600||63||firebrick||140 x 610 x 108|
|Pearl-18||top opening||925||4000||115||firebrick||457 x 457 x 216|
|PMT-21||front opening||1290||9600||290||firebrick||533 x 533 x 330|
|SC-2||front opening||1095||1680||16||ceramic fibre||199 x 204 x 145|
|Xpress E-12A||front opening||1290||2700||38||firebrick||216 x 305 x 222|
|A NOTE ABOUT FIREBRICK KILNS||OPTIONAL READING|
Fireplace, forge, and furnace bricks are very hard, tough, and solid. Often, they're not cemented together so, if you have a conventional fireplace at home, remove a brick and you'll notice a few hair line cracks and missing corners, chips, and flakes. Some might have cracked in half, but they still function. To retain heat, the bricks are dense and heavy.
A kiln made using these would be very heavy and need a much larger and stronger metal frame and case. They're hard to cut, so making joints and element grooves, and using element pins, is almost impossible. The kiln would be more expensive to make and transport and, once in your studio, would be hard to move: try lifting your night-storage heater. And a 500mm square kiln lid made from 24 bricks would probably collapse.
Kiln bricks look like fine sponge. They're light, fragile, and are made to insulate, not store heat. They heat and cool quickly so that the programmer can control the temperature. They can be cut, drilled, and made with joints and element grooves.
Unlike a fireplace, forge, or furnace, kilns are usually used for ramp-hold firings with multiple segments, so are continually cycling through heating and cooling. As the temperature changes, the bricks expand and contract and soon develop fine cracks. If the interior of a kiln expands by about 3mm per 500mm, then contracts, then expands ... something has to give.
Even assembly stresses or small changes in temperature can cause fine cracks during manufacture, factory testing, shipping, or first use. These are normal and won't affect the functionality. And the kiln won't fall apart because the bricks are held together within a metal frame. Replacing a whole set of bricks is pointless: the new set will probably develop a tiny crack immediately. To quote Paragon: hairline cracks can appear at any time, even in a new kiln.
We had a Paragon E12 in the studio for years. The first hairline crack appeared on day one and we ended up with about six, although it worked perfectly. We do have kiln-repair cement if a piece breaks away but you can't squeeze it into a hairline crack. Brushing it on might be a minimal cosmetic improvement but such a thin layer won't repair the brick.
PARAGON VULCAN MOBILE
|CASTING, CERAMICS, CRUCIBLES, GLASS, PORCELAIN, POTTERY, RAKU, AND STONEWARE|
The Paragon Vulcan Mobile is a 1290°C, eight-sided, top-opening, floor-standing, firebrick kiln, with a cone-fire ramp-hold, Sentry 12-key digital programmer. Choose Paragon black or customised blue, jade, navy, pink, purple, or turquoise.
The UK-EU kiln is rated at 230V-240V 7000W, so it needs a 30A minimum wired-in power supply. It's fitted with a switch that cuts off power to the elements when the kiln is opened: a legal safety requirement. However, never get careless: kilns are very hot and connected to the mains.
The external measurements are 864mm x 711mm x 864mm high. The case has slots for air circulation, four lifting handles, and three lockable casters. The shipping weight, including the crate, is about 200Kg.
The firing chamber measures 343mm x 381mm high internally, and heats from the sides, with the heavy-duty elements in dropped recessed grooves in the 114mm thick K-25 bricks. The kiln has a quiet long-life mercury relay and a long-life S-type platinum-rhodium thermocouple.
The firebrick lid has a fold-away lockable support. The crucible hole in the lid has a 305mm diameter firebrick cover on pivoting support arms so you won't have to find a place to lay a hot cover. It moves up and out of the way with one-handed operation. The top and the crucible cover have stay-cool wooden handles.
The programmer's electronic display prompts for heating rates, target temperatures, and hold times, making it easy to set up and re-use accurate heating, holding, and cooling sequences. The cone-fire mode, up to cone 10, will simplify your work with ceramics.
The accessories, options, and upgrades for this kiln are in the on-line shop:
a berry, blue, jade, navy, pink, purple, or turquoise respray: normally black
a programmer upgrade from a Sentry Xpress 12-key to a Sentinel Touch Screen: factory fitted
a gas injection flow meter with a controlling solenoid: factory fitted
an electric kiln vent: factory fitted at the bottom
an auxiliary power output for automatic vent control: factory fitted
a USB computer interface: factory fitted
stacking shelf kits and shelf paper
ceramic fibre cloth
HEPA dust mask
clear protective glasses
And finally, my opinion.
The Paragon Vulcan ll Mobile is a fully programmable, deluxe, professional-quality kiln for every kind of ceramic and glass work, so it's ideal for commercial studios. It's large enough to melt about 22kg of glass or hold four stacked shelves, yet it still heats up quickly. The Sentry 12-key programmer allows you to add automated gas injection, a controllable electric vent, and a USB computer interface.
The body is clipped to the base so, if a crucible cracks, the pieces will be easy to remove: if moulten glass leaks out, you'll only have to replace the floor. And, for extra practicality, the floor is reversible.
Most kilns use Kanthal A1 element wire. However, for continual high-temperature high-precision professional use, the Vulcan uses Kanthal APM. Kanthal APM has a low tendency to ageing and a low change in resistance over time. It has excellent surface oxide properties, which gives good protection in corrosive atmospheres as well as in atmospheres with high carbon potential, and no scaling. Although the kiln has these durable high-quality elements, the very long firing times mean that they're not guaranteed.
|PARAGON VULCAN ll MOBILE KILN FURNITURE|
There's a recommended kit, not included in the price: one durable round 254mm x 12mm cordierite shelf, three 12mm shelf posts, and 450gms of kiln wash.
There's an extra recommended kit, not included in the price: one round 254mm x 12mm shelf and three posts. You can choose 12mm, 25mm, 50mm, 75mm, or 100mm posts.
Depending on the material or process, and the sizes of your pieces, stacked shelves will hold more work, free up your time, and reduce the unit firing cost: so you might want more kits. This kiln has room for four.
Paragon says that the kiln will hold about 22kg of glass. However, as it no longer sells crucibles, there are some on line: just choose the right size.
The remaining sections are about digital programmers, shelf kits, options, upgrades, firing, kiln logs, accessories, materials, parts, processes, repairs, and tools. Unless you're already successfully using a kiln, they're recommended reading.
Cherry Heaven has been a Paragon distributor since 2002, and commended every year for outstanding performance. Paragon kilns are good value: buy Paragons and you could save enough to treat yourself to a luxury five-star weekend break.
Anyone can buy a kiln to resell and call themselves a specialist, but a top-tier distributor understands all the kilns, options, and upgrades, will stock spares, offers free competent technical support, can help you repair your kiln, provides on-line repair videos, has a repair workshop, and can access Paragon's extensive knowledge-base.
If you need help, you can mail an experienced technician or call . Alternatively, to learn more about how your kiln works, use the help link below the menu bar near the top of the page.
|THE PARAGON SENTRY DIGITAL PROGRAMMER|
The Paragon Sentry 12-key digital programmer allows you to set up several firing sequences, each one with up to ten heating, holding, or cooling segments. You can choose the heating and cooling rates, target temperatures, and hold times, save the sequences, and re-use them.
There are no restrictive features such as single-sequence use or pre-set programmes. Fixed programmes might seem to be an advantage. However, having diversified and experimented, most people fire materials, or combinations of materials, at different temperatures and for different times than are recommended.
The programmer is easy to use: far easier than a central heating programmer. Here are two Cherry Heaven TV programmes about setting a ramp-hold sequence. The ramp is the part where the temperature increases until it reaches the target temperature: the hold is the part where the temperature stays the same. Of course, UK-EU programmers will be in degrees Celsius.
Cherry Heaven TV provides on-line radio and television programmes on the Cherry Heaven Player. To play or pause the player, click the controls or, whilst it's playing, drag the time-line slider or volume slider to a new position.
|THE PARAGON SENTINEL SMART-TOUCH DIGITAL PROGRAMMER|
The Paragon Sentinel SmartTouch touch screen digital programmer allows you to set up firing sequences, each one with up to thirty two heating, holding, or cooling segments. You can choose the heating and cooling rates, target temperatures, and hold times, save the sequences, and re-use them. It also offers advanced and time-saving features, including optional automatic control over an electric kiln vent, a gas injection system, and a USB computer interface.
It's easy to use: far easier than a central heating programmer. Here's a Cherry Heaven TV programme about using it. The ramp is the part where the temperature increases until it reaches the target temperature: the hold is the part where the temperature stays the same. UK-EU programmers will be in degrees Celsius.
Cherry Heaven TV provides on-line radio and television programmes on the Cherry Heaven TV Player. To use the player, click the controls or drag the time-line slider or volume slider to a new position.
|KILN FURNITURE: A GENERAL INTRODUCTION||IMPORTANT|
Most kilns have a recommended furniture kit. Delivery companies have a low rate for parcels less than 30kg so, for smaller kilns weighing less than 30Kg, the kit is generally one shelf and four posts: included in the price because it fits in the box and doesn't add much to the overall weight.
You get a professional, durable, cordierite shelf with four 12mm high posts. You don't get a soft, ceramic-fibre shelf, often described as free, that will gradually break up and need replacing.
Shelf kits for rectangular or square kilns usually include four 25mm x 25mm x 12mm shelf posts, When flat, they're 12mm high: on their sides, they're 25mm. Other sizes, up to 150mm high, are available, so you can choose the shelf spacing that suits your kiln and your work. Shelves for cylindrical kilns usually have three posts.
The recommended kit is usually the simplest that works: not an expensive collection that I've put together for you. However, extra shelf kits allow you to stack your work, optimising your use of the firing chamber volume, the unit-cost of firing, and your time. And extra half-shelves or smaller shelves allow you to fire a mix of shorter and taller pieces.
For larger kilns weighing more than 30Kg, shelf kits are not included in the price because you'll probably want to choose your own mix of shelves, half-shelves, smaller shelves, and assorted-height posts.
One shelf should stay on the floor of the firing chamber all the time in case you accidentally spill or melt anything: solidified glass or metal is impossible to pick off without damaging the ceramic-fibre or firebrick.
Shelves are not meant to be an exact fit in the kiln. You need finger space all round and they mustn't scrape the kiln walls every time they're put in or taken out. Be careful lifting heavy shelves out of a top-opening kiln: if you drop them they will damage the firebricks.
Although they look tough, most ceramics break if they're dropped on a hard floor, so it's a good idea to have spare shelves, especially if your business depends on your kiln or you're running courses.
During firing sequences with heating, holding, and cooling segments, the elements turn on and off repeatedly. In a small kiln, with little residual heat, the inevitable temperature changes can make glass crack as it expands and contracts. A thick heavy shelf stores heat and, because it's resting on posts, the air circulates, helping to even out the normal temperature fluctuations.
If you're buying your first kiln, you're probably interested in one material, such as silver clay, or one process, such as enamelling. However, after a few successes, and failures, most people want to try different materials, make larger pieces, experiment with combinations, fire more at a time, and soon become interested in something else: or everything else. Some start a business or run classes.
You might want a full shelf, two half-shelves, several mixed shelves, a set of shelf posts, a bead-mandrel holder, glass separator, hot gloves, kiln wash, a knife-making rack, pyrometric cones, a tile holder, or other accessories.
Shelves are heavy, so kits ordered separately need a box and protective packing and attract an extra delivery charge. Outside the UK mainland, this might be expensive. So, if you think you'll need them, order them with your kiln, along with any other accessories, materials, parts, or tools.
For dichroics, enamelling, and glass fusing, put kiln paper on the shelf to stop the glass sticking: it's simpler and cleaner to use than glass separator. Bullseye Thinfire shelf paper, probably the most popular, ensures easy separation between your glass and the kiln shelf. One side feels slightly smoother than the other: that's the glass side.
Generally, glasswork needs radiant heat and will fuse, sag, or slump better on one shelf than between closely stacked shelves, although experienced glass artists often use several shelves successfully.
Delicate pieces can be fired on a puffed-up ceramic-fibre cloth: on a shelf. Round pieces, that could roll to one side, can be fired on a hollowed-out ceramic-fibre block. However, if the kin has elements in the bottom as with the Mini-Kiln and Prometheus Pro-7, a cloth or block will act as insulator and the kiln might overheat.
Particulates represent a health risk if they're breathed in, so wear a HEPA mask when cleaning out your kiln, mixing kiln wash, and working with ceramic-fibre blocks, ceramic cloths, and papers. And, ideally, use protective glasses.
If you want to touch anything hot, or move your kiln before it's cooled off, it's important to wear heat-resistant gloves. And, if you want to look into a red-hot kiln, even briefly, wear glare-resistant glasses to protect your eyes from IR and UV.
If your day-to-day work depends on your kiln and down-time will be disruptive or expensive, it's a good idea to have spares: extra shelves, a selection of posts, elements, a relay, and a thermocouple.
You can learn about ceramic blocks and cloths, charcoal, dust masks, glare-resistant glasses, glass separator, heat-resistant gloves, kiln vents, kiln wash, programmers, protective glasses, USB interfaces, shelf paper, tools, and other accessories, using the accessories link below the menu bar near the top of the front page. And they're all in the on-line shop.
Shelves are checked before despatch and are wrapped protectively. But they're not guaranteed and we cannot be responsible for any later damage.
|OPTIONS AND UPGRADES: A GENERAL INTRODUCTION|
It's important to learn about options and upgrades now as some have to be factory-fitted. The photo shows a Paragon Xpress E9A customised for a PMC silver clay studio: purple, with the maximum temperature set to 925°C so that students couldn't accidentally melt their silver.
An option is cosmetic or practical, such as a black respray, a right-hand door hinge, a peephole-vent, a bead-annealing door, a door or lid viewing window, or an EU plug.
An upgrade extends the standard specifications, such as a higher maximum temperature, a 3-key to a 12-key programmer, an electric kiln vent, a gas injection control system, an auxilliary power output, or a USB computer interface.
Not every option or upgrade applies to every kiln, so mail or call if you need help. However, if they're appropriate, they're listed in the on-line shop, so just add up the ones you want: but order them with your kiln as they're often difficult, expensive, or impossible, to implement afterwards. It might help if you make a few notes of your own as you read?
Kilns use regular single-phase 230V-240V mains so have 230V EU elements, not 120V US elements. The smaller kilns have UK 13A three-pin plugs: so they're ready to go. If you're not in the UK, use a plug adapter or cut off the UK plug and fit your own: it won't invalidate the guarantee. Alternatively, a special-order kiln can have a factory-fitted EU plug.
Most kilns can be re-engineered for 110V, 200V, 208V, or 220V, single phase or three phase, or 440V three phase. If you're interested, mail or call.
Although standard EU and US kilns have the same maximum temperature, set by the design and the programmer, some 1095°C firebrick kilns can be re-engineered to run at 1230°C, 1260°C, or 1290°C, making them versatile mixed-media kilns. However, to use 1290°C full-on hour after hour, choose an industrial or professional model.
Also, to maintain 1290°C, some upgraded kilns might need thicker firebricks, so they'll be slightly smaller inside: about 12mm on each side. Mail or call if you're interested, or need help deciding.
The UK factory-set maximum temperature is based on a reliable average voltage of 240V. If there's a regional, national, or temporary voltage drop, high-temperature kilns might take longer to reach their specified maximum or not reach it.
Some kilns are normally blue, but can be factory-painted berry, black, jade, navy, pink, purple, or turquoise. However, as they're made to order, they can't be returned if the colour isn't exactly the same as in the photo.
Changing the door hinge might be better if your kiln is in the corner of your studio or there's an obstacle that will make access difficult. Give this some thought.
Most of the medium-size top-opening kilns have a standard lift-up lid. Firebrick lids seem heavy to some people so, if you feel that a ceramic fibre lid, a hydraulic-assisted lid, or spring-assisted lid would be easier, mail or call.
If the kiln comes with a Sentry Xpress 3-Key ramp-hold programmer, you can upgrade to a Sentry Xpress 3-Key cone-fire ramp-hold programmer, usually preferred for ceramics. Cone-fire is implemented in the programmer's software and is very easy to use: just set a cone number and start the firing sequence.
Depending on the kiln, you can upgrade a Sentry Xpress 3-key programmer to a Sentry 12-Key ten segment ramp-hold, or cone-fire ramp-hold, programmer, with advanced firing features and connection options. The 3-key has a 12-month guarantee and the 12-key has a 30-month guarantee.
A Sentry 12-key programmer can be connected to your computer through a factory-fitted USB interface. The Control Master software allows you to control and monitor the firing, and analyse, arrange, print out, and save the data. If you want this feature, make sure you order the USB interface in the on-line shop.
Depending on the kiln, the 12-key programmer has a power-ratio feature: you can adjust the heat balance between the top and sides in 10% steps and control the heat distribution over larger pieces.
Kilns which only heat from the top, as opposed to the top and sides, don't have the power-ratio feature. However, the initial cost-saving has to be offset against fewer firing options.
With larger kilns, serious glass artists are always concerned about firebrick dust from the lid falling onto their work, so you could upgrade the standard firebrick lid to a factory-fitted ceramic-fibre lid with the elements threaded through pinless grooves in the fibre: or, as a luxury upgrade, with the elements completely embedded in the fibre.
Most kilns come with an electro-mechanical long-life nickel-chromium K-type thermocouple. However, if extra long-life and reliability are vital, you can upgrade to a mercury relay which has a lifetime of several million on-off cycles. The relay can switch 30A, so if you have a kiln that needs 50A, you'll need two relays.
If extra long-life and reliability are vital, especially at temperatures above 1100°C, you can upgrade to a long-life S-type platinum-rhodium thermocouple.
Some front-opening kilns are just too large and too heavy for a regular worktop, so Paragon makes a strong steel table, 768mm x 768mm x 718mm high, with two shelves for your accessories. The luxury version, with castors, is 63mm taller. If you decide to buy on old wood table, the rigidity of the legs is vital otherwise it will collapse like a parallelogram.
Some bronze and copper clays, and some metals, need to be fired in activated charcoal granules in a stainless steel container. The SC2 and SC3, the Caldera-A, and the Xpress E9A and E10A can hold a one-litre container: most other kilns can hold a three-litre but check the internal size before you buy the container. It's important that the container doesn't touch the thermocouple.
Particulates represent a health risk if they're breathed in, so wear a HEPA mask when cleaning out your kiln, mixing kiln wash, and working with charcoals, ceramic-fibre blocks, cloths, and papers. And, ideally, use protective glasses.
If you want to touch anything hot or move your kiln before it's cooled off, it's important to wear heat-resistant gloves. And, if you want to look into a red-hot kiln, wear glare-resistant glasses which protect your eyes from IR and UV.
Paragon kilns, made in the US, have been re-engineered and comprehensively tested for the UK, the EU, and most other countries. They're CE Marked and comply with EU safety standards. They're guaranteed for a year, and Paragon has an international, informed, and supportive user-base, and spares and repair centres.
The UK-EU digital programmer shows degrees Celsius, not degrees Fahrenheit as in the US. If you need to convert, this is how to do it. However, if you want to work in Fahrenheit, you can make a simple change to the programmer.
For help, or in the unlikely event of a fault, you can mail or call an engineer in the UK. However, home checks, adjustments, and repairs are quick and easy, needing little more than a PosiDriv screwdriver, and you can watch on-line videos. Alternatively, we can repair the kiln in our workshop at Cherry Heaven.
As with a lot of heavy consumer products made in the US but sold elsewhere, Paragon's guarantee covers replacement parts, not a return to the distributor or factory, and not any labour costs. However, as an example, replacing a programmer takes just a few minutes.
|AN ELECTRIC KILN VENT|
Refreshing the air in a kiln minimises surface blemishes when firing clays, ensures brighter colours when firing glasses, and prevents colour contamination when firing different glazes.
A factory-fitted Paragon-Orton Vent Master removes airborn pollutants straight away and redirects them to the outside through a flexi-pipe. The kilns can be factory-readied, so the vent just needs on-site assembly.
The vent motor isn't so powerful that the heat-up time and maximum temperature are reduced, but the cooling time is, depending on the size of the kiln.
The UK-EU vent motor is rated at 230V-240V 132W, so it can use a regular mains socket. The suction cup, in the second photo, and pipe are attached to the kiln but the motor can be remote: it doesn't get hot and the fan is easy to clean.
There's always a small gap, for expansion, around any kiln door or lid, so enough new air can be drawn in to replace the old air being drawn out. However, peepholes act as straight-through cold-air inlets: so you might not want them or block them with some ceramic cloth?
The vent can be turned on and off manually. Alternatively, if the kiln has a Sentry or a Sentinel programmer, the vent can be plugged into the kiln's auxilliary power outlet and controlled by the programmer. The power outlet, in the third photo, has to be fitted during manufacture, so decide before you order.
As with Paragon kilns, Orton Vent Masters can be re-engineered for any electrical system. They conform to the demanding 1992 Uniform Mechanical Code and the UL standard, and are CE Marked for the EU. They have a two year limited warranty.
|A GAS INLET FLOW METER|
Users interested in gas injection are usually experienced blade-makers. There are so many variables that there isn't a comprehensive set of instructions but I've put together enough to get you started if you're a novice.
During heat treating, oxygen forms a scale on the surface of knife blades, metals, and tools. To minimise this, the parts can either be wrapped in heat-treating foil or an inert gas can be injected into the furnace to displace the oxygen.
Most professional knife makers use gas injection for precise control and to save time. If you have a Sentry or a Sentinel Touch Screen programmer, a solenoid kit can automatically turn the gas on or off for each segment of the firing: just programme the controller to turn on the gas at the temperature where scale begins to form on the steel.
The factory-fitted gas injection and flow meter provided is a standard meter from Dwyer calibrated from 1 SCFH to 20 SCFH: SCFH is Standard Cubic Feet per Hour. The user is responsible for providing a source of gas at low pressure, less than 20 PSIG, to a 1/4" NPT female pipe fitting. A pressure regulator may be required to reduce the high pressure in bottled gas to a usable range. This is usually bought with the gas tank: it's not part of this Paragon option.
The Dwyer flow meter is for use on furnaces with internal volumes of 0.2 cubic feet to 27 cubic feet and, therefore, the setting of the flow meter will depend on the size of furnace or the amount of gas required to create a chemical reaction.
If the furnace is 0.2 cubic feet in volume and the flow meter is set on 1 SCFH, the atmosphere of the furnace will be changed 5 times per hour at room temperature: every 12 minutes. If, however, the furnace is over 1000F, the room temperature gas will expand to over ten times its volume when it's injected into the hot firing chamber. This equates to changing the atmosphere of a 0.2 cubic foot furnace at the rate of 50 times per hour: every 1.2 minutes.
It's up to the user to define how pure the atmosphere is required and adjust the flow rate accordingly. Typically, this will require several test samples to fine tune the atmosphere.
Furnaces aren't air tight and gas will leak out around the door, and through the firebricks and metal seams, so you need a steady flow of gas. Gas at room temperature will expand to over twenty times its volume when injected into a firing chamber at 550°C, so a low setting on the flow meter is adequate to prevent most scaling.
Depending on how you work, gas injection might reduce the life of the heating elements slightly. However, they're easy and inexpensive to replace. If your business depends on continual kiln time, buying a spare set of elements would be sensible.
Argon gas is popular for heat treating because it's inexpensive. But, it's heavier than air and breathing it in won't keep you alive. so your workshop must be well ventilated.
Generally, as soon as a programmable kiln starts its firing sequence, it begins to heat up at a rate set by the programmer. It can't heat up quicker than it would do with the elements full on all the time.
The thermocouple tells the programmer the current internal temperature and, depending on the sequence you've chosen, the programmer turns the elements on or off to control the sequence segments: the heating rate, the target temperature, the hold time, and the cooling rate. It can't cool down quicker than it would do with the kiln turned off. When the sequence is complete, the kiln beeps, and the sequence stops.
For safety, the programmer doesn't switch the full mains voltage. Instead it drives a relay, an electro-mechanical switch. The programmer uses a low voltage to activate the switch which turns the high-voltage high-current elements on or off.
When the target temperature is reached, the programmer switches the elements off. However, residual heat in the firing chamber allows the internal temperature to overshoot the target temperature briefly before starting to fall back.
This overshoot is more evident at low temperatures than at high temperatures, and in small kilns rather than large kilns. For example: 300°C will probably overshoot to 350°C whereas 800°C will probably only overshoot to 805°C before starting to fall back.
However, our Sentry Xpress programmers have a software modification that slows down the heating just before the target temperature, reducing any overshoot and improving the accuracy.
During the hold-time, with the elements still off, the temperature starts to fall. When the programmer switches the elements back on, the firing chamber will initially absorb some of the new heat before the temperature recovers. The continual switching of the elements on and off causes the internal temperature to oscillate either side of the target temperature.
This is similar to central heating. If you set it for 21°C, it probably oscillates, quite slowly, around 20°C to 22°C: and you won't notice. The accuracy will depend on where the thermostat is sited, how quickly it responds, how accurate it is, how long it takes for the radiators to heat up, and if you have doors and windows open. The temperature will probably be different in each room.
So, regardless of the thermocouple temperature, the actual temperature of your work will be slightly different, depending on its position on the kiln shelf, the vertical spacing of any stacked shelves, and its nearness to the elements, a lid, a door, a bead door, or a window. Learn to take this into account if you're working with temperature-critical materials or processes.
Remember that glass needs radiant heat and will fuse, sag, or slump better on one shelf at the bottom than between closely stacked shelves.
Kiln doors and lids are not meant to be a perfect fit otherwise, at high temperatures, there'd be no room for expansion and movement, and the door could stick and the ceramic-fibre or firebricks could crack.
All kilns smell a bit, and even produce whisps of smoke, during the first firings, just like a toaster or a fan heater. If you're worried about fumes, open a window.
Eventually, with normal use, kilns discolour slightly, inside and outside, and some firebricks might develop hairline cracks. Your kiln is a versatile, robust, red-hot tool: not an ornament.
|KEEPING A KILN LOG|
Using your kiln successfully needs critical research and frequent tests, especially as things that work for your friends and teachers might not work in the same way for you. It's also very important to learn how to creatively use unexpected effects. So, keep a firing log:
Buy a durable notebook. Use a new page for every firing, and draw diagrams of the shelves, their vertical spacing, and the position of your work on the shelves. Along with your work, put a few scraps at different places on the shelves to learn how things change. Describe the material, the shape of your work, the firing cycle, and the end result. Add a few photos and sketches, and mark the page corners with coloured dots or symbols as a quick reminder of your success rating.
A kiln log is vital if you're experimenting with temperature-sensitive materials or working with metals, coloured dichroic glasses, enamels, glazes, or china paints, and a skilled artist will use the kiln log to advantage to re-create effects. It'll be particularly useful if you have to repeat a commission, or you have a long holiday before returning to your studio.
Some Paragon kilns have a Sentry 12-key or a Sentinel Touch Screen programmer which can be connected to your computer through a factory-fitted USB interface. The Control Master software allows you to control and monitor the firing, and analyse, arrange, save, and print out the data. If you want this feature, make sure you order the USB interface in the on-line shop.
A BRIEF INTRODUCTION TO GLASS AND GEMS
The main component of glass is silicon dioxide, often called silica: found naturally and plentifully as sand. When it melts, at around 1700°C, it's like syrup on a cold day. When it cools, it forms a rigid brittle glass called quartz glass.
To lower the melting point, and reduce the cost of melting, chemicals are added: typically sodium carbonate and calcium oxide. Other chemicals, and different heating and cooling processes, produce a range of colours and mechanical properties.
Chemically, glass is defined as an amorphous solid but, as it's heated, it becomes softer allowing it to be blown, cast, coated, decorated, engraved, heat-treated, moulded, poured, pressed, sagged, and slumped.
A form of glass occurs naturally within the mouth of a volcano when the intense heat of an eruption melts sand to form Obsidian, a hard black-to-brown glassy type of stone, shown in the photo. Although it was used decoratively, when it fractures it has very sharp edges, many times sharper than a steel knife-edge, so was also used for tools and weapons: and the pitiful rituals of circumcision and female genital mutilation.
During annealing, fabrication stresses are relieved as the molecules cool and arrange themselves into a regular stable matrix. Successful annealing is the key to creating glasswork that will remain attractive and durable. It's quite a long process, so a kiln with an automatic comprehensive programmer is essential.
|FREE BEAD ANNEALING GUIDE|
You can download, and print, a Bead Annealing Guide. Paragon created it in 2013 so it's only a guide, not a contemporary definitive document. Click here. It's a pdf file, but your device should already have a pdf viewer.
Cubic Zirconia is the most popular substitute for a diamond because they look almost dentical. Cubic Zirconia or CZ, is made from zirconium dioxide which comes closer than any other gem to matching the characteristics of a diamond. It's not quite as hard as diamond and is slightly less sparkly but displays more prismatic fire with more colour sparkles within the gem, especially if metal oxides are added during the production process.
Caring for CZ is important because they are more brittle than diamonds and susceptible to wear and tear such as chipping and scratches over time.
Diamonds are not a form of glass: they're naturally occurring gems composed of carbon atoms arranged in a very regular pattern.
Between 1 billion to 3.3 billion years ago, simple carbon containing trace minerals was transformed into diamonds by heat and pressure at depths of over 100 miles below the earth’s surface. We can’t mine down far enough to reach the earth’s mantle but fortunately volcanic eruptions brought the diamonds closer to the surface. They're extremely hard and until recently were regarded as the world's hardest natural material.
Although diamonds are extremely expensive, their price is governed by carat, cut, colour, and clarity. It’s very rare to find a diamond that doesn’t contain flaws: however the impurities, and internal refraction and dispersion of light, give diamonds their brilliance.
Synthetic diamonds are manufactured and are identical in hardness, dispersion, gravity, refraction and chemical composition to the highest quality mined diamonds available. Whereas a one-carat top quality diamond would cost thousands of pounds to buy, the same quality man-made diamond could be made for less than £5.
This will obviously have a huge impact on the diamond industry over the next few years as when comparing a cultured and mined diamond side by side they are virtually undistinguishable. A bit like pearls, they can be grown from a single crystal using chemical vapor deposition.
Dichroic glass has two different colours: a transmitted colour and a reflective colour, both of which change depending on the angle of view. For example blue-red will be blue in transmission and red in reflection.
During manufacture, quartz and metal oxides are vapourised onto the surface of the glass using a vacuum deposition process, forming a multi-layer crystal structure.
Enamelling involves applying a glass paste to metal and then heating it to fuse it to the surface. The finish of the enamel can be translucent or opaque depending on the temperature used to melt the glass. Higher temperatures result in a more transparent and durable enamel whilst lower temperatures give a more opaque and fragile surface. Dyes and pigments can be included to produce any colour.
The Paragon SC2 is ideal for enamelling, although other kilns are fine. So click the sc2-sc3:jewellery link below the menu bar near the top of the page. The SC-2W and SC-3W doors include a 50mm x 50mm heat-resistant glass viewing-window in the centre of the door, allowing you to take a quick peep at china paints, enamels, glass, and glazes to check on their progress
To fire polish glass, return the items to the kiln and melt them just enough to give a smooth polished appearance. It needs a temperature of around 700°C, and is often used to round the edges of glass after fusing.
Fire polishing already-slumped items is more difficult because the polishing temperature is close to the slumping temperature and it can distort the appearance of the piece. So it generally works best for flat items, rather than slumped ones. It has the slight limitation that the part of the item that touches the kiln shelf won't polish.
|FUSING, SAGGING, AND SLUMPING|
If two or more pieces of glass in contact are heated, they begin to soften and fuse together. With careful heating and cooling, the separate pieces of glass become one.
If glass is put on a mould and heated, it begins to soften and collapse, or sag, onto the mould: a common technique for making bowls and plates.
Sagging and slumping are often thought of as being the same. Correctly: during sagging, heated glass, supported at its edges, sags down in the middle to conform to a mould; during slumping, heated glass, supported at its middle, slumps down at its edges to conform to a mould.
|LAMPWORK AND BEADS|
Lamp-working is the traditional name for glasswork that uses a flame to melt glass rods and tubes. As the glass softens, it's shaped by turning and using tools.
Early lampworkers used an oil-lamp, and blew air into the flame through a pipe. Later, propane, natural gas, or butane torches replaced the lamp, although kilns are now increasingly popular, particularly for annealing.
Beads are usually made on steel rods, or mandrels. When the beads are finished, the rods are removed leaving holes for threading the beads. Cold working techniques can be used, such as etching, faceting, polishing, and sandblasting.
Lost-wax burnout starts with making a wax shape and then making a mould of the shape. When the mould is heated in a kiln, the wax melts out through channels, usually over a burnout mesh and into a tray. The shape is then cast in glass or metal from the mould.
It's important to prevent wax or carbon sticking to the elements, so burnout kilns have a top vent to release fumes. Carbon build-up inside a kiln could conduct electricity and would eventually cause the elements to fail.
Paragon make kilns designed for this: the W series. So click the w:lost-wax link under the menu bar near the top of the page. They all have top vents and optional wax trays.
Moissanite is another diamond substitute which is a rare mineral found naturally in small quantities, although Moissanite for jewellery is artificially made. It’s made from Silicon Carbide which means it’s able to withstand high temperatures and is very hard.
Moissanite is noticeably much sparklier and displays more prismatic fire than a diamond which is noticeable even to an untrained observer. Moissanite does have inclusions like a diamond and it may also have a greenish tinge to its colour.
|PÂTE DE VERRE|
Pâte de verre involves making a glass paste, applying it to a mould, firing it, and removing the piece from the mould. The glass paste is usually made from glass powder, a binder such as gum arabic, distilled water, and colouring agents or enamels. It allows precise placing of colours in the mould, whereas other techniques often result in the glass straying from its intended position.
I think, currently, Daum is the only large commercial crystal manufacturer using the pâte de verre process for art glass and crystal sculptures.
This a simple technique but it requires good ideas. A bottle, such as those used for wine, beer, cola, or champagne, is softened in a kiln so that it begins to flatten out or conforms to a mould. There are too many moulds to stock here but there are lots available on line. Or make your own from clay.
The bottles need to be clean and dry, with all paper labels and tops removed. Put them in your kiln on a shelf, either with shelf paper or kiln wash to prevent the glass sticking to the shelf.
Paragon makes a kiln designed for this: the Trio. So click the trio link below the menu bar near the top of the page. It's wide enough for most bottles but can still use a regular socket.
Stained glass is glass that has been coloured by adding metallic salts during its manufacture. The coloured glass is crafted into stained glass windows in which small pieces of glass are arranged to form patterns or pictures, traditionally held together by strips of lead and supported by a rigid frame. Painted details and yellow stain are often used to enhance the design.
The term stained glass is also applied to windows in which the colours have been painted onto the glass and then fused to the glass in a kiln.
It requires artistic skill to conceive an appropriate and workable design, and engineering skills to assemble the piece. A window must fit snugly into the space for which it is made, must resist wind and rain, and also, especially in the larger windows, must support its own weight. Many large windows have withstood the test of time and remained substantially intact since the Late Middle Ages.
Swarovski Crystal isn’t a gemstone or even a crystal: it’s a form of glass made at high temperatures by melting silicon oxide powders with lead to form what is known as lead crystal. The exact process is patented by Swarovski but it has approximately 32% lead content to increase the crystals refraction index to resemble that of a diamond. To produce a diamond like effect the crystal glass is precision cut and then polished again by a Swarovski patented process that gives the crystal a high quality finish.
The crystals are often further enhanced by coating the glass with an Aurora Borealis or AB coating that gives the surface a rainbow like appearance to simulate dispersion from a diamond. Swarovski crystal is not as hard as diamond so its susceptible to scratches and chipping from wear and tear, but it’s harder than standard glass.
Tack fusing is the joining together of glass, with as little change to the shape of the pieces as possible. Tack fusing may be used either decoratively, or to assemble a large piece of glass from laminations.
Where tack fusing is used to apply small decorative details to a larger piece, you might want to partially melt the small pieces so that they change shape, usually becoming more spherical under the influence of surface tension, but without changing the shape of the carrier piece. This can be done by using an increased temperature, but only briefly. The carrier piece has a larger thermal mass, so heats up more slowly than the small decorations.
The vitrigraph process usually uses a kiln to make glass stringers. The bottom of the kiln is removed and set aside. The kiln body is put on a thick ceramic square with a central hole.
A crucible of glass is put inside, and the whole combination lifted well away from the floor to allow moulten glass to fall through a hole in the crucible and form long stringers. Ceramic squares are in the on-line shop.
Paragon make a kiln designed for this: the Caldera. So click the caldera:ceramics link below the menu bar near the top of the page. The bottom is a separate part and can be unclipped.
The term warm glass refers to fusing, slumping, and other glass processes which take place at temperatures between about 600°C to 925°C. Although that doesn't sound warm, it is when you compare it to glassblower's working temperatures, which often exceed 1100°C. Warm glass is sometimes called kiln-formed glass.
A BRIEF INTRODUCTION TO CLAYS
Clays are formed naturally over millions of years as rocks break up into minute particles. They consist of hydrous aluminium silicates and other compounds such as feldspar, iron oxides, mica, and quartz. Clays are collectively referred to as ceramics.
Clays are often divided into three main categories: earthenware, porcelain, and stoneware. Generally, they needs to be fired for several hours, although the exact chemical composition affects the firing temperatures and times, and the clays' colour, porosity, shrinkage, and strength.
All clays are created to mature at specific temperatures, and any variance can lead to unsatisfactory results in ceramic durability or color. If fired too high, clay can deform or even melt; if fired too low, your pieces will be dry, rough, and potentially unsolidified.
Historically, low-fire has been the most commonly used firing range due to limitations in kiln technology. Modern kilns are now capable of much more complex, high-temperature processes, but low-fire range continues to be popular because it allows ceramic artists to use a variety of colourants that either burn off or become unstable at higher temperatures.
The maximum cone rating of a stoneware or porcelain clay is the temperature at which it vitrifies. This is the hardening, tightening and finally the partial glassification of the clay. Vitrification results from fusions or melting of the various components of the clay. The strength of fired clay is increased by the formation of new crystalline growth within the clay body, particularly the growth of mullite crystals. Mullite is an aluminum silicate characterized by a long needle-like crystal. These lace the structure together, giving it cohesion and strength.
When clay vitrifies it gets very strong. This is especially important for dinnerware where pieces are exposed to a lot of abuse. Vitrification also makes the clay's porosity low.
EARTHENWARE, PORCELAIN, AND STONEWARE
Earthenware is normally beige, red, or white. It has the lowest firing temperature of the three, usually lower than 1150°C. It's slightly porous, and stains and chips easily, so it's often glazed to protect the surface. Its porosity means it's good for making terracotta planters and oven steamers, but not good for jugs or vases.
Porcelain is composed of kaolin, or china clay. Kaolin doesn't melt until 1800°C, so other compounds are usually added so it can be fired between 1250°C and 1400°C. For example, bone china is made by adding bone ash to the clay. It's known for its whiteness, hardness, smoothness, durability, and translucency. When tapped, it makes a distinctive ping: or ming.
Named after a hill in China from which it was mined for centuries, kaolin is the purest form of clay and is the foundation of all porcelain clay bodies. Though pure kaolin clays can be fired, often they are mixed with other clays to increase both workability and lower the firing temperature, so if using a kaolin-based clay body, be sure to note how pure your material is, as this will change the required temperature.
As a clay body, porcelain is known for its hardness, extremely tight density, whiteness, and translucence in thin-walled pieces. Another difficulty with porcelain bodies is that they are very prone to warping during drying in the kiln
When fired, porcelain becomes a hard, vitrified, non-absorbent clay body, very similar to high-fire stoneware. It also develops a body-glaze layer formed between the clay body and the glaze. The absence of any iron, alkalies, or alkaline earths in the molecular structure of kaolin not only dictate its high-fire requirements, but are also responsible for its most identifiable characteristic: its white color.
Stoneware is normally beige, grey, or red-brown. It's usually fired between 1150°C and 1300°C. It's hard, durable, and resists thermal shock. Glazes bond well, so it can be made waterproof.
Stoneware is a plastic clay, often grey when moist. Getting its name from the dense, rock-like nature of the clay body when fired, stoneware is typically combined with other clays to modify it, such as ball clays which might be added for plasticity. It is important to note that stoneware is divided into two types: mid-fire and high-fire.
Like low-fire bodies, mid-range stoneware is relatively soft and porous and has a clearly separate glaze layer after firing. However, a mid-range firing results in increased durability of the ware as well. When fired, stoneware ranges in color from light grey to buff, to medium grey and brown.
Mid-range glazes typically mature between Cone 4 and Cone 6, and most commercial underglazes have a maximum temperature of Cone 6. These glazes are more durable, still offer a fairly extensive color range, and though not quite as harsh as low-fire glazes, can still be quite bright.
Bisque is clay which has been fired once, without a glaze, to a temperature just before vitrification. Firing changes the clay into ceramic material, without fully fusing it. A second, slower, firing melts the glaze and fuses it to the clay body.
Bone china is a type of porcelain composed of bone ash, feldspathic material, and kaolin. It's the strongest of the porcelain or china ceramics, having very high mechanical and physical strength and chip resistance, and is known for its high levels of whiteness and translucency. Its high strength allows it to be produced in thinner cross-sections than other types of porcelain.
From its initial development and up to the latter part of the 20th century, bone china was almost exclusively English, with production being effectively localised in Stoke-on-Trent. Most major English firms made or still make it, including Fortnum & Mason, Mintons, Coalport, Spode, Royal Crown Derby, Royal Doulton, Wedgwood, and Worcester.
In the UK, references to china or porcelain can refer to bone china, and English Porcelain has been used as a term for it, both in the UK and around the world.
Polymer clay is a man-made material: tiny particles of polyvinyl chloride mixed with plasticisers and pigments. When it's baked, at around 125°C, the particles fuse and the clay hardens.
Raku was originally a Japanese technique, but it's now become an internationally popular way to make decorative ware, with each piece having a unique blend of colours.
A bisque piece is fired to about 950°C, then glazed. It's removed from the kiln when red-hot, and put straight into a container of combustible material.
The flames, reducing atmosphere, and mix of chemicals stain the clay. When the piece is removed and quenched in cold water, interesting colours and shades remain: often unpredictable.
|ELECTRIC KILNS INTERNATIONAL DISTRIBUTOR||KILNS, OVENS, FURNACES, PARTS, AND SUPPORT|
is a Cherry Heaven internet resource. Cherry Heaven is a top-tier international distributor for Texas-made Paragon kilns, furnaces, ovens, and accessories, and has been one of their top-selling partners from 2006 to : a pleasing outcome since the UK is only one third the area of Texas and one fortieth the area of the US.
As this is an on-line resource, there isn't a paper catalogue or a price list. However, you can mail or call a technician about kilns, power supplies, public area safety, a special project, business ideas, diagnostics, repairs, or reselling opportunities.