: dee kat - Viewing Profile

A note: If you use too much epson salt or Magnesium (what ES is) then it will go in the opposite direction. You need to titrate (add a little at a time, stir thoroughly and if there is no change in the glaze (it will thicken very slightly) then add a bit more. This is why the epson salt needs to be completely dissolved in the hot water before adding. If it were not, it would dissolve in the glaze over time and possibly tip you over the edge. If you know for sure how much you need then you can add it dry when you are mixing up the glaze. You must have enough clay in your glaze for the glaze to floculate (this is what you are doing by adding the Epson Salts). People add bentonite when they do not have enough clay in the glaze already. It is also clay that has unique properties so aids in keeping the other materials suspended.

porcelainsculptor, on 30 September 2012 - 04:22 PM, said:

Making a gas kiln I would think would be easier than an electric but much harder to fire. Simon Leach has taken an old electric kiln and turned it into a gas kiln (propane). You can usually find old electric shells that people want to get rid of because the controller has died.

If you do go the route of rebuilding an electric kiln then you are going to have to control the temperature. For the old kilns before computer controllers that was done by turning different numbers of elements on to either low, medium or high heat. So you would start out turning the bottom element on to low for a given time - for greenware you would often candle overnight so this would be on low with the lid propped open an inch or so. The next morning the lid would close and you would turn the second element on to low and run like that for an hour then the top would be turned on to low. Each hour would turn one switch up one level of heat until all were on high for all three elements. You would have a shut off switch that was kept open with a cone of the temperature you wanted to fire to and when that cone bent the setter would fall and the switch would flip to turn the kiln off. There would be a timer that turned the kiln off after a maximum number of hours as a safety measure. Any sane potter would know the timing of the firing and would check at regular intervals to make sure the kiln had not shutdown prematurely or failed to shut off when it should (so there were always witness cones on the shelves that you could look at the check your firing heat work (something close to temperature but not really).

So other than the shell you are going to need 3 sets of electric coils that will fit your kiln and a means of turning them on and off. You will need cones for monitoring your temperature. If you are going to do ramping or soaking then you are going to need to learn more than just turning on the elements and firing at high until you reach temperature. There are many posts on doing this with an electric kiln without a computer controller but you will need a pyrometer.

Youtube is good for this type of information. Somewhere I have the one on rebuilding an electric kiln but I can't find it at this time.

http://www.youtube.c...c.1.6iocYTycIL8