Fiberglass mat with Epoxy resin?

McReef · #1 03-04-2011, 02:52 PM

I have read in a couple of different places that mat should not be used with epoxy resin. The explanation given is that the binder used to hold mat together is a styrene soluble "adhesive", and epoxy, not containing any styrene like is ester cousins, will not properly wet it out as a result.

Thoughts or input on this?

My original plan was to use 1708 and 1808 biax for my project, but given that the plan is to use epoxy resin, now I am not so sure. Perhaps I should go with straight cloth instead?

Bigshrimpin · #2 03-04-2011, 03:42 PM

based on my experience 1808 does not have the glue binder, unlike 1708 which is generally has a glue binder. I have heard there are some tricks that can be used to dissolve the glue binder with a little acetone, but buying correct stitchmat that is compatible with epoxy (i.e. no glue binder) is the right way to do it. Otherwise epoxy + mat with glue binder turns into a flexible rubbery mess that never cures.

Blue_Heron · #3 03-04-2011, 05:41 PM

Quote:

Otherwise epoxy + mat with glue binder turns into a flexible rubbery mess that never cures.

Hey Tim,
I've used mat with epoxy, and though it does turn into a gooey mess, I've never had a problem with it not curing. The biggest downside I've noticed with the mat/epoxy is that it won't conform to corners or curves because the binder doesn't dissolve. Chopped strand Mat is clearly intended for use with resins that dissolve the binder.

I've also used 1808 and 2408 biaxial stitchmats and never had trouble wetting it out with epoxy.

Dave

newellchunker · #4 03-04-2011, 06:15 PM

I've been using 1708 and 1.5 oz mat with epoxy and have had NO issues! The 1708 is a bitty to get it to conform to corners but we've made due.

Seacraft84 · #5 03-04-2011, 07:17 PM

My father built two boats last year with 1708 and epoxy and did not seem to have a problem. Are some 1708 cloths different?? Is it the different mixtures of epoxy?

KenB · #6 03-05-2011, 02:50 AM

I agree with shrimp but I think there is some 1708 that is more malleable, which might work with epoxy.

My plan is to coat the back of whatever poly I plan to cover with epoxy first before laying down mat and resin... I think epoxy with less that a few days of cure will bond to fresh resin. (old poly bonds to epoxy, which bonds to new resin... old epoxy will not bond to new resin...right?)

Dumb idea? Only one way to find out!