GFA SOP

Brush up silicon with Urethane mother mold off of gypsum snap of Alginate

Run individual positives and Hydrocal sculpting full face if necessary

Sculpt appliances in water base NS Klean Klay plasticine extra firm for appliance and soft for run off

Waterclay for runoff WED or white clay require Crystal Clear or lacquer /acrylic spray

block

Mold Release

PolyTek 1512X fiberglass shell mold

Gypsum/burlap layup and gypsum layup/ Epoxical molds certainly work for silicon , but a urethane shell mold works for weight, easy vent drilling, slicker surface for removal, flexing for removal to break air lock, being able to seeing the silicon injected.

Polyester /fiberglass molds work well and the Europeans are totally sold on them. Neill Gorton’s DVD’s are stellar and I really can’t add anything else to them. I just have a problem with using polyester resin and would prefer a different approach. First coat is mud coat with Polyfiber for thickening followed by 2 layers of layup with a the softest (Bondo Home from Auto stores has worked well) 1-1.5 oz fiberglass cloth . Don’t dawdle as the Polyfiber seems to kick the 1512 faster rather than slowing down the set. The drawbacks here for those set up for gypsum molds:

You have to wear a respirator and have a hood/commercial ventilation system even though it doesn’t smell. Water is your enemy so shelf life of open bottles is short (try nitrogen or Belch squirted inside open bottles) and use plastic drinking cups and knives for mixing and chip brushes for layup.