What type of resin is used in a FG Tempest layup?
Resin…
What type of resin are you looking for?
resin
The type that WS uses during layup. PU or epoxy?
polyester
NOT epoxy. gelcoat doesn’t stick to epoxy and the fumes are odorless and quite nasty. It is also very expensive.
steve
Uh, Steve…
Epoxy fumes are not odorless. While some can become sensitized to them, they are certainly less dangerous than the copious fumes that come off a polyester or vinylester hand layup job. And while I am very much anti-gelcoat, I am sure you will find gelcoat formulations that work fine with an epoxy layup.
As for the original question, if repair is the issue, epoxy will work fine on polyester or vinylester, as I have had many opportunities to demonstrate on my own boats. I have not used vinylester on an epoxy boat, but Vladimir Vanha of Noah Boats told me that quality vinylester adheres quite well to epoxy.
Epoxy Stronger
and lighter… More costly too and probably why it doesn’t get used in large scale applications like a long boat.
sing
Agreed
Also, gelcoat CAN be used over epoxy if the epoxy is fully cured. I do it all the time on repairs.
Jury is out
in talking and working with pros in the BIG boat industry, not many will advise using gel over epoxy. while fully cured epoxy ‘may’ take a gel finish, who has multiple weeks to wait for the boat to be finished?
do a google ‘epoxy gelcoat’
it’s pretty odorless IMO. especially compared with vinyl/poly. I don’t want to breath EITHER.
repair, who said repair? yes epoxy is a better repair material IF gelcoat is a non-issue. again time is of the essence in most of my repairs.
I assumed the OP was talking Wildy production, as in hardly anyone with a volume production uses epoxy.
steve (sniffin’ poly resin as we speak!)
You may already have sniffed it too much
I think epoxy has a strong odor, though it’s not as nasty as I’d heard. I don’t even wanna think about the smell of other resins. I’m sooooo glad I finally gave in and bought a respirator for epoxy and varnish work.
A long time ago I dated a chemist who had very little sense of smell. When I visited his lab, I about fell over from the fumes. He said that many chemists actually do lose much of their sense of smell.
That might explain why he didn’t notice what happened to his piles of sweaty sweatsuits wadded inside a closed closet. Ugh.
yeppers
I have a top notch repirator tho I refuse to shave so it’s a bit of a catch 22. I strap it on sooo tight I get grooves in my face. like my face can stand more grooves…groovy dooovy.
I now just try and stay outta the lay-up room. 
steve
It doesn’t take weeks or even days…
– Last Updated: Jul-14-06 7:44 AM EST –
...for the epoxy to cure enough for gelcoat to bond properly. What I typically do is:
- Apply heat to the epoxy (with lamps or space heater) to accellerate the cure time, then let it cure for 12 hours or so, typically overnight so little time is wasted. I try to get the surface to ~100 degrees or so.
- Scrape/sand the surface to the contour I desire, which also removes any amines from the surface. Sanding provides some "tooth" for the gelcoat to bond to.
- Wipe the epoxy surface with lacquer thinner to remove any chemical contaminants.
- Apply the gelcoat, then sand, buff, polish once it's cured.
Overall, it takes a few hours longer than when using polyester resin, but the repair is stronger.
Working with epoxy
Unlike polyester and vinylester resins, there is nothing in epoxy fumes that’s either poisonous or mind-numbing. I have heard of rare cases of people who are sensitive to epoxy fumes (it’s an allergic reaction), it’s not a problem for me. A bigger concern is that it’s possible for some people to develop a sensitivity to UNCURED epoxy or it’s components if you get it on your skin (cured epoxy is inert). So, while I rarely wear a respirator when working with epoxy, I always wear gloves and avoid contact with it as much as possible. Overall, I find it far more pleasant than working with polyester resin or gelcoat.
But isn’t it different animal…
…in a production setting when you a spraying gelcoat into a mold first and then adding the fabric and resin.
oh yeah (nm)
not vinylester?
oops
yes vinylester.
sorry
steve
Why would epoxy be “lighter”?
Definitely!
I’m not advocating using this method for any kind of production boats. I use it for repairs, as it makes for a stronger repair job.
"lighter…"
because the strength is greater and a thinner coat can be used to give the same protection as a heavier coat of gelcoat.
sing
Best repairs
so Brian, you’d recommend epoxy over polyester resin for repairs on glass boats? I’m starting a major repair on a Valley boat, and have epoxy on hand. It would be much nicer to work with in close quarters inside the rear chamber, me thinks.
Another question - the stern area that’s broken has just mat fiberglass (the 6 oz. ends before you get that far back). Would you recommend I use mat or woven glass cut on the bias? I need to lay glass inside the stern to cover a break on the keel line and cracks up the side as far as the hull/deck seam, so it needs to conform to some drastic curves.
Thanks, Alan