General

Can anyone use a Kiln?

No, no unauthorized persons should be allowed near the kiln during the firing process.

ie: to touch the hot kiln case (can reach over 100 Deg C), or to look through the

spyhole or change the control settings. Kilns get very hot and can cause burns or fires if not used correctly. That said Kilns are not hard to use but people need to take precautions and follow the instructions provided in the Kiln Operation Manual.

Kiln Installation

When positioning a Kiln what are the minimum clearances I should allow?
You should ensure the Kiln has at least 200mm clearance on all sides and a minimum 600mm clearance above the Kiln. NEVER place anything on top of the Kiln. Things are often forgotten and this is a fire risk.

Basic Firing Principles

Basic Firing Principles

In the beginning go slow:

Even if you have air dried your ware for many days there will still be moisture trapped inside the clay that needs to get out while firing. If you go up in temperature too fast this trapped moisture turns to steam and can result in ware ‘exploding’ in the kiln.

Once this moisture has escaped and the organic contents of the kiln have burnt off (around 550-600C) the kiln can rise much faster without any side effects.

Remember it's all about HEAT WORK.

It's not just the top temp you must reach, it's the amount of heat and time the ware receives. This means that the Ramp rate (rate of temp rise) that occurs in the last 100C of rise is as important as the top temp the ware must reach. This is why clay often refers to a Cone number, these represent an amount of heat work. For this reason we suggest setting the last 100C ramp at 60Oc /hr. This represents the middle of the chart for a Cone firing and gives the best results. Please click here to find the latest Orton Cone Chart that shows the temp you need to reach for each Cone number.

To ensure the best results we would suggest adding a soak at the top of the cycle. This allows the whole kiln to ‘catch up’ or even out to a uniform temperature and gives a little extra time for the desired temperature to soak through the entire thickness of the ware. For bisque, stoneware or ceramics we’d suggest 10-15mins. (If you find you are getting cold spots in your kiln you can extend this soak. Uneven packing can also be partially overcome by extending this soak. But beware, don’t over do it as the clay may then over fire.)

SECOND STAGE FIRING (GLAZE):

As the ware has already been fired the ware can handle much higher ramp rates. This means that even through a glaze firing is generally to a higher temperature the total cycle time can be more or less the same.

To ensure the best results especially with glazes we would suggest adding a soak at the top of the cycle. This has two effects. Firstly it allows the whole kiln to ‘catch up’ or even out to a uniform temperature. Secondly it allows the glaze time to mature which will result in greater luster. For most glazes we’d suggest a 30min soak.

Remember just like a recipe for an Oven you may need to tweak the speeds and temperatures to get the best results.

Loading the Kiln

What safety precautions should I take when using a Kiln?

Before you begin ensure you have the correct safe working clothing to fire the kiln:

1. Mask – Class P1 minimum. (Any dust can be hazardous if inhaled)

2. Leather mittens or good quality garden gloves (ideally non combustible)(things can be hot)

3. Long sleeved loose fitting clothing non combustible.

iv. Safety glasses with infrared filters should be worn when viewing through spy holes at elevated temperatures Above 500c . The glow from inside the Kiln is a type of heat radiation and can damage your eyes.

Power

Where should I place the power point for my kiln?

If you are installing a new power point for your Kiln we would advise that it be positioned about 20cm to the right of a straight line taken from the right hand side of the kiln to the rear wall. You want the point to be easily accessible but away from the 20cm min distance from the walls of the kiln. Please ensure the Licensed Electrician follows all Australian Standards when installing a new connection, never install any electrical points yourself (it’s illegal under Australian law).

Delivery

Do the couriers install the Kiln?

No, the couriers will place the Kiln as near as they can to the position you want it but they are limited in where they can go by their pallet jacks. Any small steps, gutter bumps, grass, gravel etc will normally restrict where they can leave the Kiln. The couriers are just that, couriers, we can’t offer an unpacking and install service. The Kiln will also come packed on a pallet. The kiln can be easily walked off the pallet using two or three people. 

Moving a Kiln

What precautions should I take if I have to move my kiln, put it into storage or ‘moth ball’ the kilns for a long time?

The key thing to focus on when moving or packing a kiln is to ensure there is support for all walls within the kiln. As you are aware the Kilns are fragile and don’t take too kindly to transport. You should pack out the inside of the Kiln with boxes or the like so that all the walls and especially the roof have a small amount of support. This is so the elements and insulation don’t have anywhere to go when they are vibrated or bumped during transport. The other key consideration is ensuring the movers handle the kiln as if it’s an antique piece of furniture that is fragile and worth a lot of money and not like a second hand fridge. Removalists often see a solid metal frame and think that it take a bit of rough handling. It can’t and its worth a lot more at replacement costs than that large screen TV they’ll handle with kids gloves. 

School Kilns

What are the recommendations for Kiln rooms in Schools or Tafes?

Kiln Rooms Recommendations

Spacing

  • Kilns should be positioned a minimum of 200mm from all sides from all items except other kilns.
  • Minimum distance from top of kiln to ceiling or roof structure is 600mm.
  • Nothing should be directly above the kilns, like light fittings, fire detectors etc. Most of the heat will go straight up. Placing fan ducting here is appropriate but they should be heat and corrosion resistive. Powder coated metal materials works best. Make sure there are no plastic or meltable materials in the fan housing / grill etc.
  • These are minimum safe distances, the kilns themselves can be closer together (min 100mm between).
  • The ducting from the Kiln ventilation system should be PVC as the fan system is designed to keep temps below 80C 

Fume and Room Temperature control

  • Ventmaster Fume Extraction system recommended to be installed on kiln with ducting connected to vent fumes outside. This should be completely separate to any ventilation that is installed to handle roof ventilation. If the ventmaster system is fitted to the kiln it must be ducted outside, never have it discharge into the room.
  • Natural ventilation of the room that doesn’t involve fans is preferred but if mechanical ventilation is used then adequate make up air needs to be allowed for into the room to ensure ventilation.
  • As any fumes of heat will naturally rise to the ceiling due to convection the roof material should be corrosion and heat resistant as well as sealed so any fumes can only travel to the mechanical fan and not through things like perforated panels.

Fire detection systems

  • Any fire detection devices should be carefully selected to ensure that they are suitable for the application.
  • No matter the fan arrangement there could still be smoke and/or fumes emitted from the Kiln, the kilns outer surface will get hot and the tubes of the kiln vent/bung holes can reach in excess of 200C. This must be considered when using heat detection systems.
  • Its best to place any of these systems as far from the kilns themselves as practical to minimize the chance of any false alarms.

Second Hand Kilns

Should I buy a second hand Kiln?

Woodrow Kilns no longer deals in second hand kilns directly.

We advise any person looking to by a second hand kiln to have the Kiln inspected and tested by and experienced Kiln technician to ensure that you aren't buying a major problem. Most kilns that make it to the second hand market on Ebay or Gumtree are unfortunenatly well beyond thier usable life.

While Woodrow Kilns stopped using asbestos products in 1972 (SN# less the 1000) many other local manufacturers used asbestos as backup insulation into the 1980s.

Warranty

What are Woodrow Kilns Warranty Conditions?

Please CLICK HERE to download the Woodrow Kiln Warranty pdf for Electric Kilns.

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