ORIGINAL: jetpack
If I use water putty to form a mold, do I just simply lay the sheet face up (detail side up) and build a box around it and pour in water putty? Do I need form release of some kind? What about when I go to fiberglass? Do I need to wax it or spray it?
jetpack,
You have the box part correct, but pour the water putty in from the back side (cavity side). You will not need to wax the vacuum formed sheets prior too pouring in the water putty, because as the putty cures, it will shrink slightly. You will have to prep (Wax & PVA) the formed water putty mold just like any other mold when you do the glass lay-up for the actual part.