Wednesday, December 8, 2010

A little shelf advice, please ...



Most of the cordierite shelves that I'm using in my 17 c.f. Olympic downdraft kiln are about 10 years old now, and many are showing their age. Some are cracked and need props in stacking and sooner or later will collapse. None, as far as I can tell, are level. The leveling problem is not a big deal, since I fire on wads, but the cracking is worrisome.
Anyway, I'm facing buying maybe 10 new shelves for the kiln, and I'm not sure what to get. I could replace with cordierite, which is the cheapest alternative but heavy as hell and I'd love to not have to put in those heavy shelves in the back. I could go with Advancers and spend about $2,000 and then hope to God I never got them wet and face an explosion. Or I could go with the nitride-bonded silicon carbide, which is a bit more expensive but much lighter than the cordierite. Bailey warns about going from ambient temperature to 100F too quickly, which I guess I could prevent by just burning my igniter bars slowly up past 100, then turning on the burners.
Basically, I'd love to go with lighter shelves and save my back a bit.
Anyone out there have any advice on the matter?
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Photos: The current shelves in much cleaner and flatter years. And a temmoku pot fired on those very shelves. Oops. Not a temmoku pot at all. That's glazed in an amber ash glaze. Sorry about that.

12 comments:

cookingwithgas said...

first off that pot is a real winner!!
We bought 6 Advancers and love them and wished we had more.
I would suggest them to you- worth the price!

ang said...

oooh yummy pot!! and no idea on the shelves sorry i use whatever i'm given :P

Tracey Broome said...

When I took Judith Duff's workshop there was a lot of time spent on the discussion of a shelf issue she had and how she solved it. My A.D.D. kicked in and I can't tell you a thing she said, but you might be able to email her and get her opinion. It sounded like she had good advise from the little bit I listened to. Me and Olympic as you know had a big clash about cracking shelves, I can tell you I wouldn't get anything from them or Axner, terrible customer service!!

Peter said...

Mmm, I'm in a similar situation to Ang..., my shelves are mostly second hand ones from an old pottery factory, and have sat outside in the rain for years... I did have a shelf break after a firing once. I just started lifting it from the props and it came apart clean as a whistle, I was so lucky that it didn't do that at the peak of the firing... Treat yourself to the best that you can afford!

Dan Finnegan said...

Hollis, I have the nitrate bonded silicon carbide for my kiln and they are a dream. Not heavy at all and easy to handle. Mine have slots, I'm not sure if they all do?
I got them from Larkin and I like dealing with them.
I'm with Tracey..Axner doesn't know or care about packing shelves. Terrible.

June Perry said...

I'm using advancers in my soda/salt firings and love them. Ii had soome of the nitride bonded and a couple of them broke in half the first or second firing. Not only do you have to be careful with them at the 100 degree phase, but they don't like to get too hote either. The couple I have that didn't crack in half, are warped. I'd never buy them again. For me the advancers are well worth the price.

Kyle Carpenter said...

I'm using some older silicon carbide, but also have about ten nitrate bonded with slits, from Bailey and Larkin. I've never heard of the 100 F problem and have not had a single issue with them. Like Dan said, they are a dream. I do get a slight warp on a few, but I do have a cross draft and do fire some pretty big pots on them from time to time. Overall, I'd go with the nitrate bonded. I think Bailey stopped carrying the ones with the slits.

Hollis Engley said...

Thanks, guys. As always, a range of answers from you all. And I'll stay away from Axner, thanks to Tracey and Dan. Kyle's right, the Bailey nitride shelves have no slits any more. Apparently they were found unnecessary. I wonder about June's problem with them. Makes me a bit nervous, I guess. And I've heard lots of good things about the Advancers, other than their price. They're mighty expensive. So, thanks again, everyone. I'll have to cogitate on this ...

Craig Edwards said...

Yes, I like Larkin"s nitrate bonded shelves also.
Cheers
~Craig

brandon phillips said...

i got my shelves and the new shelves for the univ from larkin. i use the "oxide bonded" vs the nitride bonded. they are $10 cheaper and 1/8" thicker. still only about 1/2-5/8" thick. they are awesome. NEVER had one crack. Some have a little sag in the middle but only after many firings. interesting thing about the oxide bonded: they have higher working temp than the nitride and lower porosity. they also are not subject to the whole early thermal shock thing. only thing they're not good for are dampers, but no SiC shelf is. I think euclids has some info on their website for the shelves. i'm a huge fan of larkin but get a quote from euclids as well, they may be closer to you.

cindy shake said...

That pot is BEAUTIFUL! I can't wait to see the curved vessel that's in the back of the kiln load...hope you'll share :o)

Hollis Engley said...

Thanks, Cindy. The pot pictured here sits in a law office in this town. Our lawyer friend has had it for a few years. The pot in the back might be in the home of some other friends who live near here. I just saw it last weekend when we were there for dinner. But it's hard to be certain, since this photo was taken maybe five years ago.