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.
I much the same way an oven manufacturer can only give you a guide as to what temp to cook your food at we can only provide some suggestions as to some typical firing profiles for your Kiln.
When firing any ware in the kiln it is always advisable to fire to the temperature suggested by either the Clay or Glaze manufacturer. We can only suggest these basic firing profiles. If you intend on firing Glass, PMC, loss wax etc we would strongly advise doing a course in these techniques to better understand the profile you need to run to get the best results.
Yes, if the kiln is fitted with an AF+ multi-stage controller you can use the Kiln for most glass fusing and slumping. Given that glass firing is quiet complex we'd advise taking a course or reading literature from glass firing specialists like Bulls Eye Glass in the USA.
Yes and no. The upfront cost of a Gas Kiln of similar internal size compared with an Electric Kiln is substantial. This is due to three reasons:
1. Overall Kiln size: For the same usable internal area a Gas kiln has extra space on the sides where the burners fire and at the rear where there is an internal flue/chimney. Thus the overall size of the case and kiln is much larger vs its useable internal space.
2. Cost of burners: The cost of the burner assembly is much greater than cost of a Kilns electric elements.
3. Installation costs: The cost of installing a flue and gas supply is often a lot more than the installation of power. Though this may not be the case for 3 phase kilns in country or remote areas.
The cost of firing will likely be less though the time and number of firings to recoup this cost may be great.
Note: Gas Kiln also need to be baby sat as they need regular adjustment to baffles etc
No, we no longer make Gas Kilns.
Depending on what you fire you can get soot type deposits around the door seal or bung holes, most of the time this is purely cosmetic and can be expected. If you start getting a larger burn type marks you may have a problem with the replaceable door seal. Please take a photo and email us so we can provide advice as to the best solution. It may be fine, it may require some tightening of the door latch or it may be time to replace the seal.
The short answer is maybe, but you must ensure that it can't get wet from rain from that storm that happens once in a while with horizontal rain.
The Kiln is an electrical device and is not IP rated so you must ensure that no water or moisture can get on the electrics.
As the casing and frame is made from aluminium the kiln won't have any rust issues.
- The shed meets the minimum clearance requirements of 200mm on all sides and 600mm above. eg for the Hobby Fire Max you'd need a shed with min dimensions of 2400x1200x2300mm (WxDxH)
- The shed has at least two windows that can be left open to ensure adequate cross ventilation.
- The shed is completely painted or made from colour bond both sides including fittings (Kiln fumes are very caustic so all zinc or gal treated metal will rust rather quickly)
- Don't keep anything flammable in that shed. (That includes the petrol can for the lawn mower!)
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
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.
Yes you always need to protect the shelf from glazes. As glazes are effectively a type of glass they tend to stick to everything and anything. Your local pottery supplier should have a range of Kiln wash, fiber paper or stilts to help keep you glazed pieces and kiln shelves separated.
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).
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.
Though we use Air Road for deliveries across Australia, the delivery in your local area may be handled via a local subcontractor or affiliate. Thus neither Woodrow nor Air Road can be certain to the size truck available in your area. I've included a photo below of the standard delivery trucks that Air Road has in most metro areas. As you can see they aren't normally small. Please let us know asap if you have a difficult location, narrow streets, over hanging branches etc so we can work together for a solution. We do rely on you knowing the limitations of where you live and we are limited in what we can offer through the courier network as a standard delivery. But we have been able to arrange some amazingly difficult deliveries in a non standard fashion.
Moving a Kiln
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.
Kiln Rooms Recommendations
- 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
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.