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Delivery available to Remote, Rural, Regional or Metro AU, NZ & Pacific Islands
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Selecting and purchasing a kiln can sometimes be a daunting task. To help alleviate this, here is our step-by-step guide to assist you in selecting a kiln to suit your needs.
Electric or Gas?
Electric kilns are much easier to operate and control compared to gas kilns. They are easier to install and can usually be placed in a location that would be unsuitable for gas kilns, given the emissions from gas burning kilns. Consequentially, more potters, glass studios, jewellers, dental technicians and small industrial companies use electric kilns.
Gas kilns are more flexible in terms of controlling the kiln atmosphere; you can decide on oxidation versus reduction firing (we never advise reduction firing in an electric kiln). They are also ideal for raku. Another benefit of gas kilns is that they are better suited to high temperature applications e.g. porcelain (temperatures in excess of 1300c).
How much power do I have available?
A key factor that is sometimes overlooked when deciding on a kiln is the power available to operate the kiln you are considering. Typically, most Australian homes are supplied with single phase 240V 60A electricity. The standard household power point is rated to 10A only. As a result only our smallest kilns can be plugged directly into a standard power point. All other kilns will require either an upgraded electrical power point, or alternatively be wired directly to your household power. This work must be undertaken by a registered electrician, and we always advise you seek the advice of an electrician so you can budget on the cost of providing appropriate power to your kiln. In general, kilns larger than 6 cubic foot / 175L will require the provision of three phase power.
Front-loading or top-loading?
Front-loading kilns are generally of sturdier construction that top-loaders, and they tend to be more durable and resistant to everyday knocks. These kilns are generally easier to load as there is no need to bend over to pack them. Most are placed on a stand to bring them to a suitable height (or alternatively placed on a sturdy bench). Their main disadvantage is that they are more expensive to build and lack the portability of top-loaders
Top loading kilns usually has a cylindrical firing chamber. They are often suited to smaller work areas as no space is lost when the lid is opened. All of our top-loading kilns are fitted with wheels to allow for easy movement – this can be useful if they need to be moved to a storage area when not in use. They are also cheaper to manufacture and easier to transport. They are loaded through the lid and therefore each shelf must be filled before the next shelf is positioned, you need to bend over to load and unload them, and they depend upon the internal insulating bricks for their rigidity.
What is the right size for me?
When deciding on this don’t forget to make allowances for any planned increase in output as well as possible changes in the type of ceramics you are making.
To determine which size best suits you, consider the following:
What kiln furniture will I need?
The size of your products and how you intend to pack your kiln will determine how many shelves and props you will need for your kiln. Don’t forget to allow for these in your budgeting. We supply furniture kits suited to each of our kilns. We can adjust the kits to your specific requirements and individual items can be purchased separately.
Time to choose the kiln for you!
Now it's all up to you (and your finances of course!). Remember, we are always happy to help and provide advice.
Yes & No. To avoid boring you with pages of details (single phase, three phase, current, volts etc), kilns require significant current to heat up, the larger the kiln, the more current it will require.
Any kiln larger than our Craft 25 or Mercury 30 will require the use of an upgraded power point. (Check out our resources section for a chart that shows what is required). Sometimes this is a very simple task, sometimes it can be a costly nightmare! We always advise that you seek the advice of a registered electrician to ensure that you have access to adequate power to allow your kiln to perform as it should. The kiln you buy may be limited by your available power capacity, as if there is inadequate power, you kiln will be unable to reach higher temperatures, or take a very long time to do so!
Yes, it important to monitor a kiln during the firing process.
Safety should always be your paramount concern when working with kilns.
Kilns are not a ‘set & forget’ piece of equipment, they operate at extremely high temperatures and must be treated with the respect and awe that they deserve. Despite multiple safety features, your kilns component’s function in an erosive environment with extreme temperature fluctuations and corrosive gases.
Just because your kiln has a controller that can regulate the firing process, periodic checks and supervision is still essential (we recommend at least hourly).
By monitoring the temperature in your kiln, you can make sure that it is progressing through the stages as you intended. This also allows you to adjust as needed to ensure you are getting the heatwork you expected (that’s why you need to be using cones!).
Keeping a close eye on your kilns firing allows you to identify issues early and take quick corrective action. Failure to monitor and act early when things don’t seem right may result in an over-firing and potential devastating damage to your kiln and its ware.
Fire bricks are light weight, have millions of air pockets, are quite fragile and have excellent insulating properties… which is why they are used so successfully in the manufacture of many kilns.
Like everything in the kiln, the bricks will expand and contract with the heating and cooling cycle. The small hairline cracks or fissures are therefore perfectly normal and are to be expected. When the kiln is hot, all the cracks fill in from the expanding brick.
Not every brick or slab cracks right away, however it appears that all bricks in the kiln, especially the slabs, will crack eventually. Opening the kiln too early will increase the risk of bricks cracking.
A kiln that has reached a very high temperature or often endures significant heatwork, may show signs of shrinkage, cracking and browning of the internal face of the bricks and element channels.
The good news is, that unless the cracks are structural, even the most severe cracking will not affect the firing performance of your kiln.
It’s good to remember that Kilns are not designed to be airtight, they need to move and breath throughout the firing process. Its normal to sometime see the glow from inside the kiln between the bricks.
Light insulating firebricks are super insulators, but they are very fragile and easily damaged.
Every firing leads to a process of expansion and contraction – which invariably leads to cracks in the bricks. These are a normal part of a kilns life and allows it to expand & contract when fired and no way effects the functioning of your kiln.
Regular firing to temperatures more than 1270c with prolonged soaks (greater than 10 minutes) increases the amount of contraction or shrinkage. The manufacturer of firebricks (Morgan Refractory) accepts a 1 - 2% contraction in the bricks when used as designed.
However, things happen, and kilns aren’t immune to thermal or mechanical shocks! Therefore if a brick (or part thereof) has become loose, dropped, or fallen, it needs to be secured.
Using pins for repairs whenever possible (instead of lots of mortar) allows the bricks to expand and contract along the pin. Too much mortar limits the brick’s ability to expand during firing and can lead to further cracking and damage.
To repair a brick, follow these simple steps:
ALWAYS turn your kiln off and unplug it from the wall or switch off the power circuit before doing any maintenance.
You’ll need:
- Pliers.
- Brick pins (we can supply these, don’t use normal wire as it will melt!).
- High Temp Mortar if needed (we can supply a small amount of this on request).
There is no benefit in attempting to mortar over normal expansion or contraction cracks. In fact, this often leads to further cracking and damage, as the mortar limits the brick’s ability to expand during firing.
The two important things to fully understand are HEATWORK & CONES.
Mastering your kiln goes beyond relying on the controller to measure temperature and time alone. Success involves understanding the kiln itself, its unique characteristics and nuances in heat distribution and heatwork.
This knowledge enables informed decisions and adjustments, blending technical precision with a nuanced understanding of the kiln's behaviour and performance to achieve the firing results you want.
Firing ceramics in a kiln is a bit like cooking. You can set your oven on a very high heat and cook your dinner in just a few minutes, or you can cook it for longer at a lower heat. Either way, you end up with a cooked dinner.
Heatwork is the combination of time and temperature. Our imaginary dinners received the same amount of heatwork, even if they were cooked at different temperatures and for different durations.
Pyrometric Cones are still a very important tool in a potter’s armoury and the only definitive measure of heatwork.
Without a cone in your kiln you will not know whether your pottery reached temperature unless it is badly under fired. It is useful to bench mark good firings with cones and to save these results. If you are experiencing unsatisfactory results, cones will quickly tell you whether the kiln or glaze is at fault.
It is useful to place cones next to your thermocouple and in areas where you get your best results, as these are your litmus tests.
Thermocouples only measures temperature, and they do so only in the immediate vicinity of the junction (tip). Pyrometric cones measure “heat work” – which is a measure of the impact of time and temperature.
A kiln element is a piece of wire that is designed to resist the passage of electricity. As current flows down the wire, the resistance impedes the flow and so causes the wire to heat up. Element lifespan is primarily dictated by the temperature to which you fire. The higher the temperature, the shorter the lifespan.
As a rule of thumb Kanthal A1 elements will last about 500-600 firings to 1150c, 200-250 firings to 1220c, 120-150 firings to 1280c and no more than 75 to 1300c (1300c being the absolute maximum safe operating temperature of our kilns). These numbers come from Graph 1. In “Electric kiln construction for Potters” by Robert Fournier – a great book to read if you are a kiln freak! (I think they are a bit optimistic!) They are a probably best case scenarios and are meant as a guide. They assume that elements just wear out.
Unfortunately, impact to the elements in packing, glaze splatter or noxious gases will shorten the lifespan further. You may notice that as your elements age, the kiln fires more slowly or struggles to get to temperature. This is a known characteristic of Kanthal wire. It is vital that you keep the element channels always clear of debris – a small piece of broken kiln brick or broken pot that jams up against an element can cause a local “over-heat” and burn out an element. Similar situations can occur with kiln wash or glaze getting onto elements.
Our recommendation is that you carefully vacuum out all element channels before each firing and place glazed ware a minimum of 4cm from the elements – a little bit of care can make a big difference. An important feature of Kanthal wire is that after firing the wire will build up a layer of Aluminium oxide on its surface that protects it from attack by harmful gases. It will take 2-3 firings for this layer to build up. It is not a bad idea to therefore perform a couple of bisque firings with new elements (either a new kiln or replacement elements) prior to a glaze firing. The reason for this is that glazes will tend to liberate significantly more corrosive gas than does bisque ware.
We NEVER recommend reduction firing in an electric kiln
Elements leaving their channel over time is not uncommon. Cold elements are brittle, however when red hot they become soft, so if the element has slowly moved, gravity can take over and the hot element can begin to sag.
Looks can be deceiving, elements that are sagging, stretched or misshapen may be unsightly, but they may still be functioning fine. You can use a multi-meter to check their condition (a +/- 10% variance from the elements normal is a sign replacement may be needed soon).
Once an element leaves the wall of the kiln, they are not only at risk of being broken during loading, unloading but can also take up valuable space in your kiln. Therefore, if the element is still in good health, then repair may be worth a try before splashing out on replacement elements!
Before doing any maintenance on your kiln, you must consider safety:
Re-seating elements:
You’ll need:
- Needle nose pliers.
- Small blow torch (you can buy these at your local hardware shop).
- Element pins (we can supply these, don’t use normal wire as it will melt!).
Unless it's a kiln purchased through us, or one that is known to us, you'll need to send through a detailed drawing with the following information.
We wind our own elements and can typically have them made within a few days of a confirmed order, assuming you have provided all of the required information.
To calculate the cost of firing a kiln you will need to know the following:
Assuming you have one of our Fireworker 68 kilns which has a consumption of 5.5KW and you want to fire to 1220c over a 9-hour cycle, the calculation is as follows:
Consumption (KW) x Cost (per KWH) x Firing Time (Hours) = Cost
Example: 5.5 (KW) X 0.33 (KWH) X 9 (Hrs.) = $16.34 per firing.
The above calculation is based on the passage of current through the elements 100% of the time.
In a firing cycle, the current may only flow 75% of the time, so the above dollar value would be a worst-case scenario, and the likely true cost about 25% less.
A thermocouple is the sensor in your kiln used to measure the temperature. They consist of two wire legs made from different metals, which are welded together at one end creating a junction. This junction (or tip) is where the temperature is actually measured. When the junction experiences a change in temperature, a voltage is created which can then be read by your controller. There are Multiple types:
Type B - Platinum / Rhodium
Temp range: 100° to 1800°
Typical accuracy: 5°C at 1000°C
Suited for high temperature measurements. Unusually, B Type thermocouples give the same output at 0° and 42°C. This makes them useless below 50°C.
Type E - Chromel / Constantan
Temp range: -200° to 900°
Typical accuracy: 1.7°C
E Type has a high output (68 mV/°C) which makes it well suited to low temperature (cryogenic) use. Another property is thatis it is non-magnetic.
Type J - Iron / Constantan
Temp range: -40° to 760°
Typical accuracy: 2.2°C
Limited range makes J type less popular than K type. J types should not be used above 760°C as an abrupt magnetic transformation will cause permanent de-calibration.
Type K - Chromel / Alumel
Temp range: -200° to 1300°
Typical accuracy: 2.2°C
K Type is the ‘general purpose’ thermocouple. It is low cost and popular. Sensitivity is approx. 41 mV/°C. Use K type unless you have a good reason not to.
Type N - Nicrosil / Nisil
Temp range: -200° to 1300°
Typical accuracy: 2.2°C
High stability and resistance to high temperature oxidation makes N type suitable for high temperature measurements without the cost of platinum (B,R,S) types. Designed to be an ‘improved’ K type, it is becoming increasingly popular.
Type R - Platinum / Rhodium
Temp range: -50° to 1760°
Typical accuracy: 1.5°C
Suited for high temperature measurements up to 1600°C. low sensitivity (10 mV/°C) and high cost makes them unsuitable for general purpose use.
Type S - Platinum / Rhodium
Temp range: -50° to 1760°
Typical accuracy: 1.5°C
Suited for high temperature measurements up to 1600°C. low sensitivity (10 mV/°C) and high cost makes them unsuitable for general purpose use. Due to its high stability S type is used as the standard of calibration for the melting point of gold (1064.43°C)
Type T - Copper / Constantan
Temp range: -200° to 400°
Typical accuracy: 1°C
Best accuracy of common thermocouples, often used for food monitoring and environmental applications.
To changing a K-type thermocouple:
1. Ensure your kiln is either unplugged or turned off from the power point and/or the isolator switch and the breaker is in the OFF position.
2. Remove the terminal cover to expose the electrical connections in the kiln. The
thermocouple will have a yellow 2-flex cable, containing a yellow (+) and a red (-)
inner cables. Connected to the ceramic terminal block on the thermocouple.
3. Withdraw the ceramic connector (the thermocouple is connected to it). Check that
the new thermocouple is no shorter than the failed thermocouple – this will ensure it
sits a suitable distance into the kiln. Unscrew the connections of the compensating
lead to the old thermocouple and insert the new thermocouple into the kiln.
4. K-type thermocouple polarity is:
POSITIVE (+) - YELLOW cable
NEGATIVE (-) - RED cable
You will find a small length of compensating lead attached to the new thermocouple
to assist. You can discard the small length of compensating lead and connect the lead
you have disconnected from the failed thermocouple, observing the correct polarity.
5. Make sure your connection in the insulator block of both the red and yellow inner
cables is solid.
6. IMPORTANT - Replace the terminal cover ensuring that all cables are both AWAY from the kiln case (minimum 1cm) and not trapped between the terminal cover and the base of the terminal box or between the terminal cover and the kiln case. This is
critical as if the compensating lead contacts the kiln wall, then the potential exists
from aberrant readings to occur as the kiln case heats up.
7. Turn your kiln on and run a program ensuring that the temperature in the kiln is
increasing. If you notice a reduction in temperature, please stop the cycle and contact
us. If the controller shows ‘OPEN’ or E000 then it indicates a loose connection.
Repeat steps 1-7 and check for faulty connections or breaks.
Always store your kiln shelves on their end. Never store kiln shelves flat and certainly never flat stacked on top of each other. Doing so significantly increases the risk of shelves cracking.
Always use kiln wash to minimise the risk of glaze runs ruining a shelf. Regularly scrape off and reapply your kiln wash.
Always flip kiln shelves when using them in the kiln. This will minimise warping. All shelves will begin to warp, particularly at temperatures exceeding 1260c. Thicker shelves minimise warpage, but may also be excessively heavy, so making loading them difficult. The best solution is to use shelves that you can manage easily and regularly flip them. This may require the application and sanding of kiln wash on alternative sides of the shelf (if the underside of a shelf is kiln washed, then you risk having flakes of kiln wash drop onto your glazed ware, causing damage, so best to remove and clean the underside).
Always make sure you kiln shelves are bone dry when using them. If there is moisture in the shelves then as they heat they are likely to suffer expansion cracks.
Always use moderate ramp rates in the initial stages of firing up until 200c (generally rates below 120c/hr are safe). Fast ramp rates may cause rapid expansion of the shelves, leading to cracking. The same applies when cooling your kiln. Avoid rapid cooling below 250c as sudden drops in temperature will cause thermal shock and cracking.
Always use 3 props to support a shelf. This is the most stable configuration. Ensure the props are placed in line vertically, so that the load of each shelf is passed down the props.
Always check your shelves carefully when packing your kiln. If a shelf is showing signs of cracking DON’T use it. Better to replace a suspect kiln shelf than risk a collapse of furniture and ware in the kiln.
Sadly, kiln shelves don’t last forever, but by sticking to the above pointers you will prolong their life. The higher you fire, the more likely you are to experience warping and cracking of your shelves even with the best care.
We also offer not only traditional Cordierite-Mullite shelves but also Oxygen Bonded Silicon Carbide (OBSiC) and Nitrogen Bonded Silicon Carbide (NBSiC) shelves.
If you are after more information on all aspects of electric kilns, we would highly recommend you get a copy of “The Electric Kiln” by Harry Fraser (A&C Black Publishers, London 1994). It is out of print but copies usually turn up in second hand bookshops.
Except for the Metallic Black, all of our other glazes are all food safe when used as instructed and fired to maturity on an appropriate clay body.
Some people recommend the 'Lemon Test' - squeeze on some lemon juice, and leave the lemon wedge on the piece of ware overnight. If there is no colour change then leaching hasn't occurred and your pieces are suitable for functional use.
The short answer is “yes”. However underglazes are not like ordinary paints. In the firing process they undergo a chemical reaction & change colour (Compare Dark Blue in its raw and fired states).
The safest process would be to mix a ratio of two colours together and then do a test firing of that mixture, before you commit yourself to applying it to a precious piece.
Mixing the glaze from powder for dipping, pouring, or spraying:
(Note: When adding water: add very cautiously, stirring well between additions)
Using the mixed glaze:
Liquid glazes can settle out over time. They sometimes set hard at the bottom of the container, making them difficult to re-mix. To overcome this a flocculent or anti-set solution should be added a little at a time.
Epsom salts are a good flocculating agent. Adding 1% of a saturated Epsom Salt solution to your glaze mix with thorough stirring will re-suspend your glaze mix.
Glazes may also settle during use and consequently demand thorough stirring or agitation during the dipping / pouring / spraying session.
Be sure to anchor your 3D glaze by pushing down on it gently and squeezing at the same time, a bit like cake icing! If they tend to lift when drying, simply wet your finger with water and press gently on the 3D glaze.
Batt: A thin slab of wood, plaster or plastic used to support ware during shaping, so you can move it without damage. Some people also refer to kiln shelves as Batts.
Bisque Firing: The first firing of your ware, changing it from clay to pottery.
Buff Clay: A versatile type of clay, that depending on the firing temperature can be used at earthenware or stoneware. Buff refers to its colour – yellow / brown.
Candling: A very low and slow firing of the kiln to slowly dry out your ware.
Coiling: Method of building up a clay wall by layering coils (or ropes) of clay on top of each other.
Crazing: When the glaze has multiple little cracks due to high tensile stress during firing. This may or may not be the finish you were after.
Earthenware: Matures at approximately 1060°C to 1100°C – Can be quite porous so normally can’t be used in a dishwasher or microwave. Handy for plant pots as it slowly wicks moisture. Terracottais a form of earthenware.
Fettling: Removing the unwanted excess clay on a piece of greenware, normally while leather hard.
Glaze Firing: To convert the glaze that been applied to the work, into its ‘glassy surface coating’.
Glaze: A coating that when matured forms a glassy finish on the ware.
Greenware: Ware that has not yet been fired.
Leather-hard: Greenware that has partially dried to a point where all shrinkage has stopped.
Maturity: When your ware reaches its desired effects in the kiln through the effect of heat work (read the FAQ specially on heat work).
Mid-fire: A popular and commonly used clay that matures at approximately 1200°c to 1240°C.
Oxidation Firing: When you have more oxygen than fuel in the kiln. This is the standard atmosphere in an electric kiln.
Pinholes / Spangling: Faults in the surface of the clay or glaze, resembles pin pricks.
Porcelain: A super fine clay that matures at approximately 1220°C to 1300°C – Harder to throw with and more costly to fire due to the heat requirements.
Raw firing: Applying glaze to ware that has not had a bisque firing and firing both together.
Reduction Firing: When you have more fuel than oxygen in the kiln. This can be achieved in solid fuel burning kilns (wood, gas etc). It’s NOT recommended to try and achieve a reduction firing in an electric kiln.
Slip: A liquid form of clay that can be used for decorating or slip-casting (putting it into moulds to get complex shapes etc).
Stoneware: A high-fire clay that matures at approximately 1260°c to 1300°C – very durable and non-porous. However, given the impact of this high temps on electric kilns and element life-span, many people are moving to modern Mid-Fire Clays that can achieve the same results at a lower temperature.
Turning: Trimming and shaping ware while in the leather hard state.
Ware: Is what we call objects that are made from clay and happen to be one of the earliest human inventions!
Wax resist: Using liquid wax on ware where you don’t want glaze to be repelled (part of the design or the bottom of ware so it doesn’t stick to the kiln shelf).
Wedging / Kneading: Preparing clay through working it by intermittently throwing on a bench, needing & cutting. The intent is to remove any air bubbles and make sure the clay is a uniform consistency.
Mix up some kiln wash with water until it is the consistency of milk. Its better to make it too runny than too thick, otherwise it might crack off your shelf before you even put your shelves in the kiln!
Brush this runny mixture onto only one side of your kiln shelf with a soft brush and allow to dry. You will still see some of the shelf colour through the kiln wash. Apply a 2nd coat to the shelf and allow it to dry. You may need to apply a third coat.
You will know when you have applied enough when you can no longer see the colour of the shelf through the kiln wash and your shelf appears white. Once you have done this, leave your shelves to dry overnight.
The shelves will have soaked up water with each application of kiln wash, and you don't want to fire damp shelves in the kiln as they may crack. Therefore, fire your shelves 1st in a bisque firing – i.e. fire them slowly, rather than fast.
That way you will be able to use your shelves for many firings - up until the kiln wash starts to crack off the shelves (10 - 20 firings if you look after them). When needed, scrape it off the old kiln wash (we have Rub Bricks to help with this), turn your shelf over, and apply new kiln wash to the other side of the shelf.
Flipping your shelves periodically helps prevent them from sagging.
If you apply kiln wash to the underside of your shelves, or don't remove old kilns wash once you flip a shelf, when it starts to peel off it may fall on your pieces in a glaze firing!
We started this business in 2020 to provide, reliable, versatile, and solid kilns & pottery equipment at a price point that is more affordable than many other suppliers. Here are a few pointers to consider.
1. Kilns generally consist of a range of generic parts that are readily available from any kiln manufacturer, or kiln repair technicians. The bricks are generic, so is the element material as well as the contactors (they control the current from the control box to the element). The only unique item on a kiln is the controller. We supply a range of controllers suitable for the type of kiln chosen, however it’s possible to chop & change controllers or add a new controller to an old kiln.
2. We carry a full range of spare parts specific to the kilns we supply and are happy to provide as required. We also wind Elements for all our kilns, and any other kilns provided we have the specifications (check out the FAQ on ordering elements above).
3. Fortunately, there are no moving parts in kilns, however they continually expand & contract with each firing! Keeping on top of your kiln’s maintenance prolongs the life of your purchase. By taking care of the lining, particularly in loading and unloading, your kiln should last many, many years. There are several very experienced kiln technicians that can perform repairs if required.
4. We offer a 2 year warranty on our kilns. This covers any fault in manufacture only, not wear and tear or the ubiquitous brick expansion cracks etc. Elements and thermocouples are also considered consumables as their lifespan is dependent on use (like tyres on a car).
Surprisingly we hear this a fair bit, however our products are not cheap, we work hard to make sure they are affordable! We keep our margins small, over-heads low and seek out functionality & reliability above how things look!
Our kilns are manufactured by some of the worlds most respected and experienced kiln and furnace manufacturers in the United Kingdom, Holland & South Africa.
Other products are sourced locally or imported from New Zealand, Taiwan, USA, China & India. We have been able import them at what we think is a fair market price.
We are generally open Monday to Friday from 9am to 5pm and occasionally on Saturdays mornings for special collections. We are a functioning factory, so it's best to call us prior to coming to ensure we are available to help you with your needs.
Once we receive your order through our website, we will double check with you that you have appropriate electrical capacity and also what sort of freight / delivery / collection (for kilns) you prefer.
We will then email you an invoice.
If you believe your shipment is incorrect or has items damaged or missing, please call or email us immediately and await our instructions.
Always take photographs of any concerns or damage to products and its packaging. This will be essential evidence if an insurance claim is required.
Email us at TechSupport@firedupkilns.com.au if you need more information or have any suggested inclusions.