Shrink wrap for Mold Release

[LMB]

Anybody know if shrink wrap will work for a mold release? I've put together a plywood box to be used as a male mold. Just looking a quick and easy way to seal the surface.

[War Whoop]

Do a test with your resin system.

[Herman]

Use packing tape instead, less wrinkling.

[LMB]

Yeah, packing tape was what I started with but since it has no stretch it's difficult in the compound ( or reverse compound) corners.

[hoytedow]

I had success with saran wrap on a small project using grp many years ago and I believe it is similar plastic. Be careful of folds and overlaps.

[latman]

sorry i am late to post but i would brush waxed polyester onto the wood (eg surfboard filler or finish resins), then a coat of mould release wax or PVA and lay up over that surface ,you could also use car bog (bondo) against the plywood and sand that to nice curves before you paint the polyester resin on.

I think the plastic film may "float " too much ,but the weight of your laminate may hold it down ? and deal with all the wrinkles later.

[Lurvio]

I used packing wrap on my prop blade (4 x 9 cm) mold and it worked, kind of, I was using polyester resin. I would not use that material for anything larger than your palm and not anywhere near a flat surface. Maybe a thicker plastic and tape the corners. Or better yet, try book cover film that has its own adhesive.

Lurvio

[LMB]

As a follow-up.. I tried the shrink wrap on a test piece and it did not work very well. The wrap "swelled" as it cured. It may have had to do with the heat lamp I was using to speed the cure but the combination of mild heat and solvents caused some swelling in the plastic. Ended up using packing tape and alot of release in the corners. Faired and refinished after we pulled the part. Turned out nice.

[hoytedow]

Originally Posted by LMB

As a follow-up.. Turned out nice.

Good thing. Congratulations.