Ok, dumb question. My fiberglass container says don't apply if under 60 degrees. What if you apply it say at 70 and it drops during the night to 60 or below. How will it affect the cure if any? Thanks
Fiberglass question
- Thread starter paulh1
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It may take a little longer to cure to 100%. I don't think the resin stops curing until it get to some ungodly low temperatures.
and some boats are still curing a year after they leave the factory. One thing to be wary of is DEW condensing overnight. Water DISSOLVES uncured polyester resin, so if dew gets on it, you can end up with pockmarks and - if there is enough of it - actual holes through what you thought was going to be solid 'glass. Covering the work (along with the light for warmth) should help avoid this problem.
Yes cover it with some visqueen (that plastic sheeting you use for a paint drop cloth). The visqueen does not stick to the resin and it helps keep the surface very smooth. The resin does not cure by drying out but through a chemical reaction so keeping it covered helps. And the reaction produces it's own heat so covering helps hold in some of the heat.
Are you using polyester or epoxy? I've used both and epoxy is better for many reasons.
1) Epoxy will stick well to polyester but the reverse is not as true
2) Epoxy does not smell as bad or make me feel sick when I accidentally breath the vapors (wear a proper mask either way)
3) Epoxy will reach a hard cure state (not tacky) faster. The polyester resin will sometimes harden fast enough and then stay "sticky" for days. And I've noticed that the quality of the resin (how dark it is) varies a lot from batch to batch with the Bondo polyester resins.
4) Uncured epoxy washes off of your skin with white vinegar (keep a bottle handy), polyester is a sticky mess that seems to get on you and stay on you.
5) You can thicken epoxy with all sorts of things so it is easy to make a nice glue or fillet filling with it. Talc powder works as does graphite, saw dust and several commercial fillers. It is very versatile.
6) It is not as expensive if you buy it in larger quantities
Here for example
http://www.ebay.com/itm/230732090356?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649
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I'm using a polyester gelcoat with polyester/fiberglass resin filler. The bad thing about the filler is it's green. I've done some test pieces(used an old piece of pvc pipe)and found that if you sand too hard on the dried gelcoat the green bleeds through. I'm running out of time where I live as the temp is starting to drop. Would like to get it done before winter. I suppose I could use the gelcoat and heat it with a heat gun or hair dryer till it sets up???
In cooler temps, add a little extra MEKP to the polyester. Poly and epoxy will both cure in lower temps, but take a little longer. You can add extra hardener to poly but don't ever change the epoxy ratios. If the resin surface of poly remains tacky, it is because there was no air dry in it. Great for laminating. Please don't even think about adding gelcoat to epoxy.
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