To Drill or Not to Drill

[Stacy]

I have just bought a cheap dish to slump over and was wondering if I was right in saying that I don't have to drill a hole in it unless I am slumping 'into' the mold - if I am slumping 'over' (ie an upturned dish). This is what I am planning on doing tomorrow but wanted to ensure I wasn't going to get any trapped air.

Ta
Stacy

[Dennis Brady]

I have just bought a cheap dish to slump over and was wondering if I was right in saying that I don't have to drill a hole in it unless I am slumping 'into' the mold - if I am slumping 'over' (ie an upturned dish). This is what I am planning on doing tomorrow but wanted to ensure I wasn't going to get any trapped air.

Ta
Stacy

You're right that you don't need vent holes in the mold if you're draping over it (slumping is when you go into a mold).  The glass falling over the mold as it drapes pushes out the air.

HOWEVER....you should avoid placing that dish directly on the kiln shelf.  Draping over a mold that is pressed against the shelf traps air inside the mold that acts as insulation to prevent the mold from being the same temperature as the glass.  On the ramp up, the glass will heat up quicker then the mold - resulting in thermal shock cracks.  Place 3 small supports (kiln posts, pieces of ceramic tiles, or small pieces of 1/4" float glass) under the rim of your mold to permit air to flow inside the mold.

[littlegiggles]

If you ever try slumping without the holes... kinda happens but doesnt work well.... if you then turn the plate your slumping upside down to flatten it out... the air gets trapped ... but you end up with beautiful blue shards of glass which work great on beads... means you cant give the plate as a wedding gift tho

[♥♥Tan♥♥]

LOL