Monday, November 29, 2010

A new test kiln, and looking for some serious kiln washing advice.



Well I'm back from my time in North Carolina. I don't have any pictures of the firebox right now, but I'll get some soon, and put up a post then. I had a great time in NC, and really enjoyed building the kiln for Julie. Julie and Steve were great hosts as well. It looks like I'll be headed back down in the spring to put a few finishing touches on the kiln and join in the first firing. Should be good.

Now that I'm home though the first order of business is to put together a proper test kiln. I took the scenic route home through the mountains of North Carolina (I ended up spending the evening at Alex Matisse's home, and got to see his new kiln/kiln shed/studio, if you haven't seen it all yet I recommend a gander: Alex's blog). I stopped by Bandana Pottery (Michael Hunt and Naomi Dalglish) and Shawn Irelands and was very impressed (not for the first time mind you) by the depth and quality of their glazes. Christy and I made the decision to stop salt glazing when we left North Carolina to give ourselves more glaze options to explore. It's been a slow learning process, and seeing Shawn/Michael/Naomi's glazes reminds me how much more there is to learn. Don't get me wrong I like the glazes we have, but they comprise a very narrow section of all the possibilities.
So first step? Rebuild our test kiln.

It's served us well for quite some time now, it's very efficient, and easy to fire. However it cools very, very quickly. This has caused more than a few unpleasant surprises while unloading new glazes from the wood kiln which tends to cool rather slowly.
My first thought was just to put a thick layer of cob up around the outside of the kiln. However this still leaves us with a lid that is heavy to lift on and off the kiln and cools just as quickly.


And I also imagine that putting up insulation outside the stainless steel exterior of our kiln would cause the steel to deteriorate pretty quickly.
So I think we will keep the burners, and build up a new kiln around them. I'll have to invest in a little bit of metal to hold it all together, but I'm hoping to keep other expenses to a minimum. The thinking now is to build it up so it looks something like a little square bottle kiln. Something that can be loaded from the side, and then bricked up.

So I don't want to use the best bricks as I would like to save those for building Christy a earthenware kiln sometime down the road. Here's what I would like to use:


They are grate brick we got from our trips to Iowa. We got them the first couple of trips simply to act as a border to keep the small brick from tumbling out of my Father-in-laws trailer. Later on we built sides on to the trailer. They are obviously in rough shape. My thoughts now are to grind the interior side clean, and pack the hollow section with clay and sand. I then want to put up some kind of kiln wash to protect the bricks. The grate bricks have had a hard life, and I don't expect them to last forever, but I think with a little TLC they should last at least a little while longer.
So I am interested in peoples experience with different kiln washes. I want to keep any kind of atmosphere from reaching the bricks (I may want to add a small amount of wood or wood ash during the firing to see how our glazes react... an idea I got from talking to Micheal Hunt about their test kiln). I don't want to spend too much money, so no ITC coatings or something of the like. Lastly I don't want to put anything on our kiln that is going to later flake off, both getting on our test pots and making it necessary to rewash the kiln.
Any ideas? I've heard of people glazing their kilns with a high alumina shino glaze. This has a serious appeal to me, but I don't have any experience with it. I feel as though put on too thinly the standard EPK/Alumina mix won't protect the brick as fully as I would like, and put on thickly it tends to flake off after a matter of time.... If I thought I could cob the inside of the kiln and not have it flake off later I would... but I don't see how it wouldn't end up on our pots eventually.
Any thoughts?
Joe

6 comments:

bryce brisco said...

have you read jeff campana's blog about self leveling kiln wash...pretty interesting

Joe and Christy said...

Bryce,
I just checked out the article, thanks for the link. It is a well thought out kiln wash recipe and article. Maybe a starting point for what I am looking for. I think as it is it still has a fairly high probability of eventually flaking off. I could be wrong though.... he does mention being sure to get it off of the edge of the kiln shelf to avoid it falling on pots at a latter date. My current thoughts are that maybe starting with something like Jeff's recipe and adding a little bit of feldspar so that during the first firing it will harden and form a glaze like skin.... as it is I imagine it still stays as a somewhat powdery surface. Perfect for protecting shelves from glaze, but not so perfect for vertical surfaces. These are just my thoughts though, and I welcome other thoughts/opinions.
Joe

brandon phillips said...

john britt just had an article in CM a few months ago about kiln wash. have you read that?

Ron said...

No thoughts from me on kiln wash. But I'm glad you had a good time tooling around NC. I totally agree about Shawn's and MH's glazes. The best. And MH and Naomi's new little kiln is pretty sweet too. (oh and the baby is cute too).
Good luck w. the test kiln. Have you considered firing down the old test kiln to make it not cool so quickly? Not the ideal solution probably.
Look forward to seeing the firebox pics.
Ron

Joe and Christy said...

Brandon,
I don't get CM, but I just finished reading it online... some good info there. I'm now thinking something along the lines of:

25 calcined kaolin
25 kaolin
50 alumina
5-10? G200 feldspar
possibly some Darvan 7?

thanks for the heads up.

Ron,
Things got pretty crazy at the end of the kiln buiding. So my 'tooling' around NC after the kiln build got severely shortened. Hopefully next time though I can make it out your way for a visit. I haven't ever fired down our test kiln... I'm trying to come up with a good excuse for why I haven't ever done that.... give me a second.... um, nope, can't come up with any good reasons. Our electric kiln shell gets less and less solid as time goes on. Every firing a new piece seems to fall off of the wall. We even have a couple of holes in the floor.... that's my excuse for a rebuild.... still don't have one for not firing down...
Joe

ang said...

i have seen some soda kilns washed with what looks like a high alumina wash maybe do some searches for soda kilns you should find something on youtube sorry i can't remember the link..