[Jocelyn]

I just did a kiln firing, and - unknowingly - the top of one of pieces was in contact with the underneath side of the kiln shelf (the side without the kiln wash).

Is there a way to remove the glaze from an un-kiln-washed shelf? I don't want it to drip off in a future firing.

Thank you.

[Mark C.]

You will need to grind it off. A 4 inch portable power grinder will do the job fast or a bench grinder with guards removed (carefully)
The glaze needs to be ground off till clean shelve shows and all glaze is gone.
Mark

[SShirley]

I have a shelf like that. The pot below was just a tiny bit taller than I thought. It just left a colored ring that's a little glossy but it doesn't stick out or anything. I didn't grind it and use it all the time with no problems.

[Marcia Selsor]

I had the same experience as Shirley. I didn't grind it. It is just a slightly colored ring and is not going to drip.
Marcia

[WillowTreePottery]

I have done this a few times. An angle grinder as someone suggested is a good option. Another short term solution I've used is to use a chisel and just gently pop off any ragged edges.

[Mark C.]

As noted you do not have to remove that glaze as it will just soak into shelve next fire and not drip.Think of your shelve like a sponge-Glaze gets on it and will soak into a mullite (shelve material) when heated up again. You can grind it off before this happens or fire it and let it soak up.I like clean glaze free shelves . If you leave it on not much harm will be done-the choice is yours.
Mark

[clay lover]

Interesting, Mark, I have always ground off any glaze. Are you saying that the glaze drips will soak into the shelf and unglazed feet of pots can sit on the spill area and not fuse together in future firings? I hate grinding off spills, but also hate trying to load a shelf around the spots that I haven't ground off yet.

[Mark C.]

clay lover, on 28 May 2012 - 02:09 PM, said:

Interesting, Mark, I have always ground off any glaze. Are you saying that the glaze drips will soak into the shelf and unglazed feet of pots can sit on the spill area and not fuse together in future firings? I hate grinding off spills, but also hate trying to load a shelf around the spots that I haven't ground off yet.

Glaze will stick to your glazed drip areas on feet unless you remove the glaze. I suggest grinding glaze off shelves when glaze drips. The problem Joceyln was having is the shelf bottom. The unwashed side.

Glaze will soak into any part of a shelf and I suggest grinding it away always but on the bottom you do not have to. I would but not everyone does and that's fine. Keeping your shelves clean is just part of the process. I'm not keen on taking out the trash but I have to. Mark

[DAY]

"Best practice" is to flip shelves with each firing, to preclude warping. But we all ignore that advice, right? And not much of a problem, if the shelf is not overloaded and the firing is not cone 10. Unless you are a "messy" potter, or using a very runny glaze, kiln wash is not really needed. (insert angry response here. . .) Better to put a glaze catcher under each piece. That way kiln wash does not flake off the upper shelf and ruin the one piece that would have certainly found its way into the permanent collection of that world famous museum.

[TxBeekeeper]

DAY, on 29 May 2012 - 07:29 AM, said:

"Best practice" is to flip shelves with each firing, to preclude warping. But we all ignore that advice, right? And not much of a problem, if the shelf is not overloaded and the firing is not cone 10. Unless you are a "messy" potter, or using a very runny glaze, kiln wash is not really needed. (insert angry response here. . .) Better to put a glaze catcher under each piece. That way kiln wash does not flake off the upper shelf and ruin the one piece that would have certainly found its way into the permanent collection of that world famous museum.

I take old broken soft kiln bricks (cheaply bought a stack of them off a guy who repaired kilns. I make thin slices on my table saw or with a hand saw. These wafers make nice glaze catchers and crumble off easily when glaze does drip into them. Their porous nature makes them easy to grind off the pot.

I have seen 'glaze gone wild' when the school ended up with a contaminated batch. Not only did the kiln shelves absorb the glaze removing the pots left giant craters in the shelves and 2 levels of shelves were so badly damaged they cracked in multiple directions like shattered glass. Expensive.

[Mark McCombs]

Hi Everyone,


Just another question on grinding. What is the preferred composition of a grinding disk for cleaning off shelves?

Or specifically, what disk to use? My grinder uses 4.5" x 1/4" with a 7/8" mounting hole.

I had one pot go south on me and dropped half its glaze off and I have a bit of cleaning up to do.


Thanks.

[JBaymore]

Mark McCombs, on 15 August 2012 - 02:48 PM, said:

Hi Everyone,


Just another question on grinding. What is the preferred composition of a grinding disk for cleaning off shelves?

Or specifically, what disk to use? My grinder uses 4.5" x 1/4" with a 7/8" mounting hole.

I had one pot go south on me and dropped half its glaze off and I have a bit of cleaning up to do.


Thanks.

Mark,

I think you already saw my reply on this elsewhere .... but ..... just in case..... a diamond wheel. Hot knife through butter.

best,

..............john

[ayjay]

For those thinking of buying, is there any preference for which type of diamond disc?

They are available with either a continuous edge or a toothed edge, I've used a toothed one before now for carving pots around, but a continuous edge might be less likely to chip or break things.