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Re: fiberglass resin = polyester
By:Shawn Baker
Date: 4/25/2001, 6:42 pm
In Response To: stich&glue/fiberglass (don dupere)

: I'm wondering if I can use fiberglass resine over the fiberglass clothe.

Actually, fiberglass resin isn't really fiberglass resin at all, but polyester resin, which is usually used for fiberglassing. The third type of common composite resins, next to polyester and epoxies, are vinylester resins, but I digress....

: According to the plan I have to use epoxy in the joints and over the
: fiberglass.

Stick to epoxy. Mixing ratios are easier to measure and get right, and you'll end up with a better boat. Epoxies are stronger and tougher than polyester resins. Polyesters can be very brittle, and have poor water resistance, compared to epoxies.

Polyesters also aren't very good glues. Polyesters stick well to polyesters, so they bond well around fiberglass cloth, and for that reason, work well for an all polyester/fiberglass layup, but they don't have as good of adhesion properties as epoxy. Epoxies stick to damn near everything, which is why they're used to join the panels together at the joints, and to bond the wetted out fiberglass cloth to the wood boat below. There are a few examples of polyester resins working well on wooden boats, but these are the exceptions. There are far more where the glass cloth will blister or peel away from the wood, losing all positive benefits you hoped to gain.

Polyesters are stinky, flammable, and difficult to mix properly. You are probably considering them because of their generally lower cost, but there are some epoxy manufacturers with good epoxies that are actually less expensive than polyester resins. I think you'd be glad in the long run if you stick with epoxies and skip polyester.

I have used polyester resins to do repairs on solid fiberglass boats, but I'd be very hesitant before putting polyester on a wood boat.

Check out:
http://www.raka.com
http://www.shopmaninc.com/epoxy.html

Shawn

Messages In This Thread

stich&glue/fiberglass
don dupere -- 4/25/2001, 6:14 pm
Re: stich&glue/fiberglass
Nick Schade - Guillemot Kayaks -- 4/25/2001, 7:32 pm
Re: stich&glue/fiberglass
Shawn Baker -- 4/26/2001, 12:08 pm
Re: stich&glue/fiberglass
Paul G. Jacobson -- 4/27/2001, 2:18 am
Re: vinylester
Lee Gardner -- 4/26/2001, 9:25 am
Re: vinylester
Geo. Cushing -- 4/29/2001, 10:48 pm
Re: fiberglass resin = polyester
Shawn Baker -- 4/25/2001, 6:42 pm