wax less Polyester resin and PVA

[lesburn1]

So here is the issue, I want to make some vacuum bagging tools and I have polyester resin on hand that is wax less. Can, after I layup my last layer of glass to make the mold (tool) and the polyester resin gels up spray on a coat or two of PVA to insure a hard cure of the outer most layer?

[tinhorn]

I say yes, you can. As I understand it, it's the reaction to oxygen in the air that keeps the skin tacky. No oxygen, no tackiness. To insure "hard cures", I've placed parts in sunlight. Because God prefers fiberglass to aluminum, He's filled sunlight with ultaviolet rays that will cure even low-catalyst layups.

Not sure you'll like the finish, though. I've never seen a raw polyester or vinyl ester part that wasn't full of pinholes. This is why God created gelcoat.

[Doug Lord]

Why would you invest in tooling made of polyester? And you know that naked polyester is going to want to absorb some of the moisture when you wash off the PVA...

[Landlubber]

lesburn1,

When making tooling, we first make a plug, the mould is then laid over the plug, the resin sets and the plug is removed, and the mould tool is created, you seem to be arse up in what you are doing mate.

[lesburn1]

Lets see if I've got this right.
First I need a plug to make my tool.
Yes, got that.
Put on the gel coat and glass to make the tool.
Yes, done that part before, know about that.
So, to get back the the original question,
if the outside surface (not the molding surface) is still
tacky, can I use PVA to promote a full cure?

Thank you "tinhorn" for an answer. (although I'm not sure that god concerns herself with my molds)

[ondarvr]

Yes, it will reduce or eliminate the tack of the resin, but it needs to be used very soon after the resin is applied and still uncured, it will do almost nothing at a later date.

[pacific808]

yes you can!