Sanding Sealer alternative to Duratec

[scherzoja]

I'm having trouble with parts sticking to molds and would like to know an alternative to Duratec Gray Surfacing primer. I used that in the past and it worked well, but now days I only need small quantities: a few cups at a time, over 6 to 12 month interval. Duratec works really well, but I just can't get small quantities around here and can't store it because it solidifies after a few months. I've wasted more Duratech than I've used because the very short shelf life, especially when opened.

I had some recent failed parts/plugs, even though I sanded to 2000 grit and waxed the surface be ore spraying the gelcoat and layup.

What can I use as a final coat to sand into a mirror finish, so the parts won't stick to the mold?

For mold release, I use Partal #2 paste.

I tried some 1 part sanding primer from an autoparts store, but that didn't work.

Thanks

[pcmm]

Get some PVA. It’s great as a release agent. I’ve used it to make 2 large deck lockers. Once you’ve made your plug or mold, just brush on a couple of coats and nothing will stick to your plug or mold. And it’s inexpensive too. Once you pull your part, just wash it with some water as PVA is water soluble.

[Benz]

Sticky molds, especially when new, are part of the boatbuilder's life. Most boat shops will do 2 coats of wax on a fully-seasoned mold between cycles, and I've done 8+ on a new mold and still had sticky issues.
Best thing to use as a mold surface is tooling gel--comes in orange or black and shines up better than Duratek.
After dozens of sticky molds, I've become a believer in PVA. It doesn't give you the perfect surface you want, but the time saved in not hammering and cussing a sticky part out of a mold can be put toward sanding and painting the surface, and somehow my surfaces always need some repair.
If you use PVA, it hardly matters what the mold surface is, nor whether it's perfectly smooth.
Also, if you care to pony up some serious cash, the modern wipe-on mold releases commonly used for pre-preg and vaccuum-bagged parts are far more slippery and involve way less elbow grease than wax. A primer coat and two topcoats are usually enough.