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I'd like to use 1/4" fiber felt to make a custom drop mold, which would create a spoon rest. Looking at the ceramic spoon rest that I currently own, it looks like I should make an oval and then a long slot that goes all the way to the edge.
Here's the ceramic spoon rest And here's my crude sketch on fiber felt of the cut I would make (it's a circle rather than oval to match the glass design) All the drop molds I've seen are symmetrical and have no cuts through any edge. So will this work or will the glass just run out the open end?! I realize I could just retain the closed edge and it would probably still work as a spoon rest but I am interested in the question of an open end anyhow.
Sorry if this is extraordinarily dumb.

I'm not sure why you're wanting to do a drop mold. That would be a lot of heat, and bottle glass doesn't flow like art glass. Why not just make a plaster mold of the top of the spoon rest, then do a clay slip to create the positive?
Or better yet, just let the bottle melt naturally flat on the kiln. You're just melting a bottle, right? Why go through the headache of creating a mold for something so simplistic - unless you plan to mass produce these.

Hi Judd,
Sorry I wasn't clear. I'm not slumping a bottle. I'm slumping art glass.
I fused two layers of art glass and now I want to make a spoon rest with it by slumping it through a custom mold made of 1/4" fiber felt, on 1/2" posts.

I can make the drop mold with a round spoon shape and a long slot for the spoon handle, and I can just end the slot before the edge of the mold. But I was just wondering what would happen if the slot for the spoon handle continued all the way through the edge of the mold.

It's really a general question about molds with an opening on one edge - whether that's possible or if the glass would slump not only through the mold opening but out further than the edge of the mold.

There's a simple solution to that potential problem: Make the mold longer on the open end than the glass you'll be slumping.

OP - if you have only fused 2 layers of 3mm glass, there is no problem to the handle "groove" extend out past the glass. The glass is not going to travel down it, due to the 1/4" rule. 2 layers are 1/4" thick. Glass travels outward if thicker than 1/4", inward if thinner. I'm curious if you are planning on using ridgidizer on the cloth followed by kiln wash. Gonna be rough without and only one time use.

Thanks, Edpal! Yes, I am using rigidizer and kiln wash on the mold.

adds-on. There is no rule against using a piece of thin-fire(I prefer Papyros but anyway ) under your glass to obliterate the cloth texture a bit more. I like that spoon rest idea: using a drop for the "drip catcher" area That way you can leave a nice big edge like your original item. Will be interested in seeing the final result.

Oh, good reminder about using PAPYRUS (same here, love Papyrus to line the mold.

This may all be moot, as this morning I fired the molds with rigidizer (from Delphi), and not only did it stink to high heaven but it turned everything with kilnwash - shelf, posts, floor - BLACK. I got the worst of it off the floor with a drywall sander, but I am more than a little annoyed. Especially because the molds are now SOFTER than before I fired them and two of them immediately ripped right through. WTH!

On the one that is still intact - Do I add hardener again, dry in the oven again, and fire again? Or just throw them all out and make molds from something else? (That's a rhetorical question BTW... )

FusedLightStudio wrote:Oh, good reminder about using PAPYRUS (same here, love Papyrus to line the mold.

This may all be moot, as this morning I fired the molds with rigidizer (from Delphi), and not only did it stink to high heaven but it turned everything with kilnwash - shelf, posts, floor - BLACK. I got the worst of it off the floor with a drywall sander, but I am more than a little annoyed. Especially because the molds are now SOFTER than before I fired them and two of them immediately ripped right through. WTH!

On the one that is still intact - Do I add hardener again, dry in the oven again, and fire again? Or just throw them all out and make molds from something else? (That's a rhetorical question BTW... )

Well, it's not an exact science. My technique has been to apply ridigizer, let dry, candle on a hot kiln, repeat maybe 4 times. Then fire once. Then kiln wash 3+times.
Smell - got a propane barbeque grill ? That will burn off a large portion of the smelly, organic components although many aren't released until a bit higher... Good luck - prepare a fan, just in case.

Low fire clay.