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kiln building

Posted: Sat Sep 26, 2015 12:36 pm
by Dick
I think I am resigned to building a kiln. Several questions. I know I want a brick bottom, but have seen and used kilns with a mix of fiber and brick above. I know the benefits of each, as to quick heating and cooling or retention, but what are your ideas for the best meet in the middle? Brick sides and fiber roof, or just brick bottom and fiber sides and roof? This will be a bell kiln somewhere between 4'x4' and 4'x6'. On the fiber should it be board or blanket, or does that matter? Also, for planning purposes, where can I find a formula for calculating amperage based on kiln size?

Thanks

Dick

Re: kiln building

Posted: Sat Sep 26, 2015 1:53 pm
by Brad Walker
I'm sure Bert will chime in, but here are my thoughts.

Brick bottom, fiber top and sides. Board easier to work with than blanket, and sheds less. Elements in quartz tubes to prevent drooping.

Here's some element info from Dudley Giberson: http://www.joppaglass.com/elements/dudl ... r_2012.pdf

And from Euclid: http://www.euclids.com/Html%20pages/element-design.htm

And from Duralite: http://www.duralite.com/kiln-furnace-studio.htm

When I last built a larger kiln (some years ago), I called all three companies above to ask for recommendations. Surprise! They were all different! In the end I just went with my own best guess, based on recommendations from the three.

Re: kiln building

Posted: Sun Sep 27, 2015 12:30 am
by Rick Wilton
I've built three kilns all based on exactly what Brad had stated.

Good luck, but it's not that hard. The first kiln I built I figured I'd need to change this or that to perfect it. 9 years later it was still firing perfectly.

I recently moved out of my large commercial space and had to downsize and the Big kiln had to be sacrificed. I mourned the death of that kiln, I salvaged parts and pieces so it'll live on in another kiln.

Re: kiln building

Posted: Sun Sep 27, 2015 1:15 am
by Dick
Thanks Brad and Rick. I too, mourned selling my kiln when I had to close up the studio. If I had had any money I would have put it in storage. Oh well. Not too worried, but always good to get some other views. I figured the board would be a lot easier, but see so many with blanket, I had to wonder if there was a reason.

Re: kiln building

Posted: Sun Sep 27, 2015 2:22 am
by Rick Wilton
I believe blanket is cheaper and easier to get. I built all of mine with board though.

Re: kiln building

Posted: Sun Sep 27, 2015 8:57 am
by Bert Weiss
The interface I like is steel to brick. The steel frame of the bell (or clamshell) sits on brick. I don't like the idea of steel to steel. In that case, both pieces of steel will warp in opposite directions. One piece of steel warping is not a problem. I just built a kiln with cast fiber floor surrounded with standing bricks. The panels are 3" thick so the walls are 6" high. I made my bell with 6" walls. I also had panels cast with embedded elements. I haven't yet fired it up. We have to wait until my client gets her occupancy permit.

In the past I always built with 5" thick brick floors.

Yes blanket is cheaper, but it is also less durable.

Years ago, I bought Chinese bricks and they really sucked. They were crumbly. I'm told they are better now. I just bought some for the kiln I just built, and they seemed good.

My refractory supplier of choice these days is http://www.ceramaterials.com They have warehouses dotted all over.

Re: kiln building

Posted: Sun Sep 27, 2015 9:11 am
by Bert Weiss
In general, fiber is far superior to bricks. You have to pay to heat bricks up, and wait for them to cool down. The reason we use bricks on the floor is because they don't warp. I took a chance and made a floor with 3 - 3" thick cast panels with ship lapped joints. The boards were made a bit denser than standard HD. I glued them together, and after the initial firing, I'll caulk the joints with refractory caulk, then sand them smooth. My client uses thinfire paper. So, the goal is to fire directly on the thinfire on the floor, without the seams being evident. We'll see if this works or not. The alternative is an expensive large piece of wet felt. This kiln firing area is about 40" x 84".

Re: kiln building

Posted: Wed Sep 30, 2015 6:34 pm
by Valerie Adams
Jeremy Scidmore teaches a kiln building class here in Northern California. I believe it's about $1650 and each student makes a GL-24 equivalent kiln.

Here's the link; registration closes October 16:
http://www.publicglass.org/#!iv-designs/ckso