Lids Sticking To Jar During Firing

[dooarts]

i've been told to fire lids and bottoms together (nested), so they end up the same size. i'm having trouble with the lids sticking to the bottoms sometimes, and am wondering if there's a simple way to keep that from happening. (the two surfaces that nest are always glaze-free) thanks

[Min]

Mix up some alumina hydrate with your cold wax resist and use this on your galleries. Approx a heaping teaspoon to about 1 cup of wax resist. I add some food colouring to my resists, different colour for the stuff with the alumina. (keep it off the glazed parts or you will get a rough glaze finish)  After firing just brush off the alumina hydrate from the gallery. 

[Pugaboo]

I agree use alumina hydrate. I fire lots of lidded boxes and it what I use. You only need a little don't go overboard, I did when I first started using it and have rough ugly marks on my box from where it seeped over onto the glaze. Now I wax the lid with regular wax and then use alumina wax for the body gallery and it works really well for me.

 

T

[MatthewV]

Potters fire lid+base together because different final temperatures will change the fit. Firing together also helps keep the roundness. The alumina hydrate wax is certainly the correct way to solve this problem.

 

With most newer kilns, or with lids that don't fit too tightly, it would be possible to just put the lid on the shelf next to the bottom. It takes up more space but should be completely suitable most of the time. For beginners who aren't so careful with glazing and cleanup this will be more successful.

[Mark C.]

I just dip my wax sponge in alumina powder as I wax the lid.

I always fire the lids on and as its cone 10 porcelain it will stick if not hydrated.

If the ever stick which does happen I use a 2 inch diameter foot log piece of bamboo to tap them apart

This is a learned skill taping such lids as to not break them.

[Marcia Selsor]

I put 2 tsps of Alumina Hydrate into a small bottle of Aftosa wax. I wax the lids and feet of porcelain to avoid problems. After the firing , it washes right off.

Marcia