darticus

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[TD="class: alt2"]I have some older Dumas fiberglass sailboat kits. They refer to polyester resin being used to put sections together. They use this to glue deck to hull etc. and also refer to it as fiberglass resin. They mix it with Cab-o-sil to make thicker when needed. According to the fiberglass resin instructions this sets up pretty fast and to put a deck and hull together in 9 minutes gel time is very fast to work. Is this what we should use to put things together and at this quick speed? I have in the past mixed a two part epoxy and put sections together but is this a usable method today. The fiberglass method is what was used in the 60's and 70's as this is when these instructions are from. I have more recently used West System 105 epoxy resin part 1 with West Systems 205 part 2 fast hardener to bond in the past. I think this method is a slower bonding method. I have also added microfibers to this to make it putty like. What is the new procedure for bonding fiberglass sections together today? Both methods above are older methods. Thanks Ron
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kzimmerman

epoxies in general don't hold up well when gluing polyester components. The best thing to use is polyester resin. With polyester, you can reduce the "gel time" with the amount of catalyst you put into it, and also with temperature. The hotter it is, the faster it sets. I've never had a problem with it setting up to fast if mixed right.
There are epoxies that claim to stick well with polyester based components, but I have seen them fail on numerous occasions.

darticus

West System 205,105 Expoxy does say it can be use for fiberglass construction. I have used it but never put it under sailing pressure. I know it has a work time much longer that Fiberglass Resin which says 10-15 minutes. To mount a deck to a 36 inch hull and tape and make sure spacing is correct I think will need more than 15 minutes. Thanks Ron

kzimmerman

I have used the west systems to bond polyester components, and it failed. The problem has something to do with the polyester. Don't know what it is. Anyways, if your dead set on using epoxies, try to find some aerospace grade epoxy. I forgot what they call it, but were going to a rocket launch this weekend, and they use alot of there, I'll try to find out. It works the best of anything I've seen, but you still have to scuff up the polyester side really well, scrub it with acetone, and let it dry for a couple of hours.
Good luck! Post photos!

darticus

It sounds like I better use fiberglass resin. I want to get enough work time. Maybe someone can tell me the best way to mix. I have to put a deck 36 inches on a Dumas equation hull. The deck needs to hang over 1/8 inch all around. They say to put tape spacing 2 inches all around after the deck is in position. They do say to mix the resin with micro fibers. They say to remove some tape after setting and cut or remove the extra resin and microfibers and put tape back, then do the next tape spot. Hope this resin doesn't get rock hard fast. I'm adding a copy of the instruction for this section so you can advise. If I screw this up the kit will be wasted. Thanks Ron