Fiberglass surface still somewhat sticky


New Member
Hello! I have a problem regarding fiberglass for mask making. The thing cured a couple days ago, it is rock solid and indestructible; however the surface is tackier than honey. Should I mix more hardener next time?

Also, should I give it a coat of spray paint before dremel work? It's very difficult to touch right now.
Thanks for reading!


Active Member
This usually happens if you don't mix the proper hardener to liquid ratio. Depending on how little you used it could take a couple weeks to fully cure. It also depends on how your weather is, if it's not hot enough the material won't cure right either. I'm going with the former but if weather might be the problem I would let the inside of the piece or whatever area you fiberglassed sit in direct sunlight for 15 mins or so just to give it a jump start especially in the damper areas.

Another trick you could use is to lightly brush some hardener on the tacky areas like you would put butter on some biscuits :). If it's still a little tacky after that I would brush some fullers earth powder or foot powder to help absorb some of the tackiness. After that a coat of flat black krylon paint inside the pieces should help seal the deal.

You could tell I've had this problem before many a time so I hope this helps you out!


Sr Member
It's possible, If you did not first apply "Gel coat" to your mold, and used only "Laminating resin", then the surface will remain sticky for a while. Laminating resin is formulated to stay tacky, so additional layers can be added after the initial cure. "Gel coat" and "finishing resin" cure to a "waxy" hard finish. Hence, why these are used as the first layer and the last layer.
Improper mixing (unless way off) is not usually the cause for the surface to be tacky only. If the body has cured, then your ration was likely OK. The other possibility is if you made your part in an RVT mold. Most RTV silicones will inhibit the curing of polyester resin. This would also explain the surface being sticky, but the part being cured as a whole.