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Thanks for the help on power rating. I now have two new queries
Do i go for Quartz tubes with elements inside or Mullite with elements wrapped around, (just roof elements) and what are the pros and cons of ceramic fibre only on walls and roof (4") as against backing fibre with board(2"+2"). I'm looking for efficiency of firing as i have limited power.
Any advice greatly appreciated
Thanks Michael

Michael,
When I was in Ireland last summer I ran into a glass blowing studio not far from you that blows glass. He uses old Coke bottles as his cullet. I am sure that he has an annealing kiln. He might be able to give you info as to where he got his parts. If you don't know who he is e-mail me off line at the1glassman@yahoo.com and I will look up his info... As to what products you should use, I am no help there.

Good luck,
Stuart

Michael wrote:Do i go for Quartz tubes with elements inside or Mullite with elements wrapped around, (just roof elements) and what are the pros and cons of ceramic fibre only on walls and roof (4") as against backing fibre with board(2"+2"). I'm looking for efficiency of firing as i have limited power.

You can use either quartz or mullite, either will work. A third option is thin quartz rods, which go inside the element just like the mullite. It's likely that the mullite or quartz inner rods will break over time, but this shouldn't be a major concern. I'd use whichever item is easiest or less expensive to obtain. (When I talk to experts in the US, they seem to prefer the one they sell..... )

4" of ceramic fiber may be slightly more efficient than 2" + 2", but the difference is probably not that significant. Remember, 1" of fiber alone has significant insulating value; for example, for 1" thickness, if your kiln is at 1200F equilibrium on the inner facing, it will be only around 350F on the outer facing. If you have 2" of fiber, the outer side temperature has already dropped tremendously, so the additional insulation from more fiber is not that significant.

Michael wrote:Thanks for the help on power rating. I now have two new queries
Do i go for Quartz tubes with elements inside or Mullite with elements wrapped around, (just roof elements) and what are the pros and cons of ceramic fibre only on walls and roof (4") as against backing fibre with board(2"+2"). I'm looking for efficiency of firing as i have limited power.
Any advice greatly appreciated
Thanks Michael

Michael

All of the systems can work well. The system I have seen that I like is quartz tubes with the elements wound around the outside. The tubes go all the way through the kiln walls and in to a chamber on the outside of the kiln walls. There is a fan that is set up to turn on at the point where the kiln is cooling slower than the program calls for. It is a system to help dissapate heat from the kiln when it is holding more than desirable.

The system i use for elements is also a good one. I use 10 gauge nichrome in straight wires, not coils. The nichrome is supported by J-hooks made with a lighter gauge of nichrome. The element is strung back and forth 1" apart all over the roof. On my large kiln I have 3 zones. This setup makes for the most even heating possible. The 10 gauge nichrome is stronger and will last longer than thinner wires coiled. nichrome also has more strength than kanthal. It requires less support. I looked in to encasing niichrome in quartz, but found out that it won't work. This system is outlined in Henry Halem's book Glass Notes. I got it from plans used to make the kilns at Pilchuck back in the early 80's. I built my first kiln in 1982 or 3 and the elements are still going strong.

Good morning Michael,

You can see some links to suppliers I found whilst making my kiln here;

http://www.artemisglass.co.uk/studio5/s ... ninfo.html

You can save a lot of money buying stuff in the States.

Michael- I'm partial to elements inside quartz. Go see http://www.duralite.com