Kiln building questions-K-26 fire brick for a Kiln?

chknifemaker

chknifemaker

Joined
Jun 30, 2013
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I have heard of people ordering K-23 type brick for a kiln but is there any real difference between k-23 and k-26 for a kiln?
and is it okay to use the 9" x 4.5" x 2.5" brick size? I thought the 2.5 thick would be okay?
Thanks
 
K-26 is denser and stronger than K-23.

Edited to reflect Tim's info.
 
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The K26 tend to be a bit denser. This means there's a bit more thermal mass and the heat-up time will be marginally longer for a K26 oven vs a K23 oven that is otherwise identical. The K23 is also a better insulator than the K26, so heat loss, and therefore power consumption, at any stable temperature will be higher with the K26.

I've built kilns with cheaper, denser no-name 2300 degree IFBs and with Thermal Ceramics K23/JM23 IFBs. The cheapies are worse than the JM26s in terms of both density and insulation. Both have worked pretty well. In an ideal world, I'd use the K23/JM23s, but the difference in performance is not particularly great; if it's for hobby use, use what you can get and do not worry about it.

If you are looking at a kiln for heavy/professional use, I'd recommend holding out for the 3" K23/JM23s.

A useful thing to know is that unglazed Porcelain floor tiles will take stainless HT temperatures and make a cheap but resilient replaceable floor. Mine developed a big lengthwise crack on the third heat cycle, but has not deteriorated any further since and still does the job. The IFBs are pretty soft and tend to suffer a bit of damage without something like the tile.
 
Maybe try for insulation a Ceramic Fiber Boards + Ceramic Fiber Blanket for about 2600*F max working temp.
Kiln is lighter and better insulated.

For one small kiln you probably need a one 50mm board (1x2m you have material for 2 kilns and pack of 2600*F Glue ;) ) + 50mm blanket as second layer.

With this material you have small temp. loss.

And if kiln is heated from 3 sides ( side walls and floor), above floor Heat element, is nice to use 0,5mm tungsten plate.
 
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I filed the element grooves into my first build, but life is just too short and I use a router to cut the element grooves now.

I really do not want to be routing ceramic fiber, so have not tried a brickless construction. I think it could work well if you can deal with the safety considerations, but these are not trivial.

I built one of my HT ovens using IFBs for the walls carrying the elements, IFBs for the floor and 1" of 2300 degF- rated CF board backed up with 3" of Calcium Silicate board for the door and roof. The main reason was that it was a quick-and-dirty build of a sword-length oven and I was trying to avoid having to cut a lot of bricks. The inside of the oven was 9" wide and I needed an easy way to span the gap. With only Carbon steels to deal with, it gave me some wriggle-room to try different materials.

Having tried it and found it to work, I am pretty sure I'll be using CF board/Calcium Silicate insulation setup again. Having found the Porcelain tile works for the floor, I'd be happy to make the front door, back, roof and floor from the board/Calcium Silicate and just do the element-bearing walls in IFB.
 
Hi timgunn1962,

I know this thread is a bit old, but just wanted to check how your fiber board + calcium silicate setup has held up over the years? I'm looking to do the same thing for a small electric ceramics kiln. The floor and walls will be fire brick + 3" calcium silicate board, and I'm thinking of doing 1" fibre board + 3" calcium silicate for the ceiling and door. How hot were you heating your oven?

Would really appreciate your advice, as I haven't heard of anyone else using this setup for a small kiln.

Cheers,
Ollie
 
olliejb said:
Hi timgunn1962,

I know this thread is a bit old, but just wanted to check how your fiber board + calcium silicate setup has held up over the years? I'm looking to do the same thing for a small electric ceramics kiln. The floor and walls will be fire brick + 3" calcium silicate board, and I'm thinking of doing 1" fibre board + 3" calcium silicate for the ceiling and door. How hot were you heating your oven?

Would really appreciate your advice, as I haven't heard of anyone else using this setup for a small kiln.

Cheers,
Ollie
Click to expand...
Hey mate I am having problems setting up my electric kiln, can you help me out please, I am using REXC100 PID, 2500W heating element, SSR 40 0-32DCV and a LED transformer 20-40DCV....it gets going for a few minutes but then the heating elements stop heating my email is renchasfresh12@gmail.com
 
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