Fiberglass application question
11-22-2005, 08:15 PM
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Fiberglass application question
Two questians: Would it be better to put a coat of resin over a balsa hull, let it dry, sand, and then go on with the fiberglass process so the balsa wood did not soak up most of the resin.
How many drops of hardner would I use per ounce of fiberglass resin, I once used 15 drops per ounce per instructions and the fiberglass did not stick to the wood very well.
How many drops of hardner would I use per ounce of fiberglass resin, I once used 15 drops per ounce per instructions and the fiberglass did not stick to the wood very well.
11-22-2005, 08:48 PM
#2
RE: Fiberglass application question
You have to follow the directions very carefully. Say if the temp is below 70 i think it is. It takes a longer time to dry. as for 15 drops to an inch thats a little bit to much i think. I use about 4-6 drops to about a once. As for the other question you can apply the resin first then apply the cloth and resin as a secound coat. Am currently working on the USS Missouri made by sterling. And i have done the same process. so far so good. Hope this help's.
08-06-2006, 10:45 PM
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RE: Fiberglass application question
I only have one suggestion and this isnt an ad but a fact, but West System Epoxy, they have a website....best resin in the world as far as I'm concerned
08-21-2006, 10:59 AM
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RE: Fiberglass application question
I'm gonna say I agree as far as epoxies go, West System is great stuff -- as far as epoxies go.
If you're only experienced with polyeseter, though, you may want to think about it before switching... epoxies are tougher than polyesters (harder to sand), more expensive than polyesters, and less forgiving of inacurate mixes or marginal temperatures because they're not just a catalyst like polyesters use: their "hardner" is actually part of the reaction and needs to be there in the right proportion to get a proper cure.
The good things about epoxy are that it sticks to more different things and it USUALLY doesn't smell, as polyesters do. (Note the emphasis on USUALLY... ).
To my way of thinking, there's no need to get the absolute best-est resin in the world any more than there's any need to use carbon fiber matting, nickel plated hardware, mil-spec motors, or a number of other things that are top-notch for extreme applications, but just more expensive inplaces like warship combat where the inexpensive materials are already stronger and better than the usage really demands. For your boat... do whatever is comfortable for you -- because it's pretty much ALL good!
If you're only experienced with polyeseter, though, you may want to think about it before switching... epoxies are tougher than polyesters (harder to sand), more expensive than polyesters, and less forgiving of inacurate mixes or marginal temperatures because they're not just a catalyst like polyesters use: their "hardner" is actually part of the reaction and needs to be there in the right proportion to get a proper cure.
The good things about epoxy are that it sticks to more different things and it USUALLY doesn't smell, as polyesters do. (Note the emphasis on USUALLY... ).
To my way of thinking, there's no need to get the absolute best-est resin in the world any more than there's any need to use carbon fiber matting, nickel plated hardware, mil-spec motors, or a number of other things that are top-notch for extreme applications, but just more expensive inplaces like warship combat where the inexpensive materials are already stronger and better than the usage really demands. For your boat... do whatever is comfortable for you -- because it's pretty much ALL good!
09-05-2006, 08:55 PM
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RE: Fiberglass application question
Epoxy sanding dust is a class A carcinagin. Polyester is much more body friendly. It can be broken down and passed by your system. That said epoxy is a much tougher substance and better suited to use with wood. But I will not use it because I would like to one day meet my grandkids and I breath alot of grinding dust (even with my booth air system and mask)
If you are coating your entire skin with cloth, poly is fine.
Cat rates range from 1% - 2% with 2% yeilding a very short pot life of less then 15 minutes and 1% giving about 20 - 30 minutes depending on temp. I use medical type measuring cups with cc increments on the cat. With one quart of resin, 1% is 10cc's of catalyst and 2% is 20cc's. You should mix 8oz of resin at a time so that you can get an accurate mix. That makes the range from 2.5 to 5cc's. Undercatalyzing causes long cure times and resin runout before cure. Then the material cures kind of rubbery and soft. Overcatalyzation causes the resin to thicken quickly making it hard to absorb into the material and cures brittle with possible fragmentation cracking in the worse case scenario.
Mixing one ounce at at time and adding drops to it is asking for trouble. If you start mixing and just a fraction of the cat. splashes out of the cup or absorbs into a mixing stick your ratio is thrown way off.
If you are coating your entire skin with cloth, poly is fine.
Cat rates range from 1% - 2% with 2% yeilding a very short pot life of less then 15 minutes and 1% giving about 20 - 30 minutes depending on temp. I use medical type measuring cups with cc increments on the cat. With one quart of resin, 1% is 10cc's of catalyst and 2% is 20cc's. You should mix 8oz of resin at a time so that you can get an accurate mix. That makes the range from 2.5 to 5cc's. Undercatalyzing causes long cure times and resin runout before cure. Then the material cures kind of rubbery and soft. Overcatalyzation causes the resin to thicken quickly making it hard to absorb into the material and cures brittle with possible fragmentation cracking in the worse case scenario.
Mixing one ounce at at time and adding drops to it is asking for trouble. If you start mixing and just a fraction of the cat. splashes out of the cup or absorbs into a mixing stick your ratio is thrown way off.
