Fiberglass surface still somewhat sticky

Alrightman

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!
 
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!
 
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.
 
I bought this Stargate serpent guard helmet off of the late SgtFang years ago and have never done anything with it. I don't think he did this one. I'm not sure who he got it from. I think I'm finally going to get off my butt and work on it. But I'm having the same issue. I wiped on some acetone and then tried again later with a toothbrush, but it's still a bit tacky. Having never done anything with fiberglass, I'm not familiar with any of the products used. What is the name and a brand of hardener I might try. Thanks

DSCF6429.jpg
 
You could try some MEKP (Polyester resin catalyst) brushed on the surface, in a small area, to see if this solves the problem.
Note: MEKP and MEK are not the same thing. In this case the "P" is very important. MEK is a solvent, you don't want to use this.

The other solution may be some heat. I wouldn't put this in your household oven, but depending on where you are, you could make a hotbox in the sun. I would guess 130-150 degrees f could help. We had a piece in our shop that had a similar issue, and it was stored in a hot storage container and the stickiness went away.
 
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