I remember, in class, it was mentioned that it might be possible to use a mold without breaking it. Perhaps not one that you make. Is this possible or am I just dreaming?
We had a similar question on another thread. I asked Bonnie for her advice on the question of reusable molds for pate de verre. She wrote:
I think that slumping molds can be used in pâte de verre, just not in exactly the same way as in the workshop & current pate de verre videos (Bullseye Online Education). This is on my list to explore as the question comes up often. I've seen a piece or two done this way...
Moisture is a pretty key component in the pâte de verre technique shown in class (& video lessons). Packing a wet plaster/silica mold helps the water & gum arabic frit mixture stay hydrated, which also helps lock the grains into place w/ tamping. It all works together and is dried at the same time.
Approaches with slumping molds tend to compete with this idea of having moisture in both the mold & the frit, because of how release agents work. I'd choose primer over Thinfire as I think it would conform to the mold better.
A primed (slumping) mold may be effective - though I expect will have a different feel when packing. A dry mold helps the primer layer stay in place but may work against keeping the frit in place. If I were to try this, I would try to pack the mold in a way that would generally keep the primer layer intact to protect the reusable mold (& the piece). I would try an open, gently curved mold rather than one with sharp interior angles. I'd also lean towards a lower process temperature than used in the class/video & probably not use talc.
There are many different approaches to pate de verre. You could also try fusing a pate de verre piece (flat), then slump it in a mold... There's lots of room for adaptation & experimentation!
I hope this helps!