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View Full Version : Cursed fiberglass casting molds



LaenaMarsh
05-01-2019, 10:33 AM
I am trying to cast scale molds, and I did a new round of fiberglass resin. It's not clear all the way through, and the clay isn't lifting up nicely like it did with plaster. Was it not enough hardening medium? Is it possible to do too much? I was doing 10+ drops for 1 ounce, mixing 2 ounces at a time.

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Mermaid_Rain
05-01-2019, 12:22 PM
I wish I could help :( so far, I have stuck with 1:1 resins and plaster, because the precision needed fornfiberglass resin worries me

Merman Storm
05-01-2019, 02:14 PM
Polyester resins are very forgiving in how much catalyst you use. If you use too much, it hardens quite fast and gets hot. Too little, and it just takes a long time. Even if you were to mix just one drop into a gallon, it will, eventually, harden.
My guess: mold release. Mold release is like violence and lube you use to get into a tail: If its not working, you are surely not using enough of it.
For now, you may just have to scrub the clay off. Try brushes and paper towels.
Make little samples of clay, apply different mold release types and thickness, then put on the resin. Once you find something that works, please tell the rest of us.