Boat Building Forum

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Re: Should work great
By:Julie
Date: 11/4/2003, 11:36 am
In Response To: Should work great (Paul G. Jacobson)

: Stitch and glue construction was developed long before epoxy resin was a
: common item. *ALL* the early stitch and glue boats were built with
: polyester resin, and many still are. It works well.

: When you coat your boat with epoxy you'll cover it with a wonderful
: waterproofing material. Polyester resin does not soak into the pores of
: the wood as well as epoxy does, and, on a microscopic basis, polyester
: resin is very slightly porous, so it does not prevent the intrusion of
: minuscule amounts of moisture into the wood as well as epoxy does. That is
: only a concern to people who build boats which spend all their lives in,
: or on, the water.

: Polyester resin comes in two basic styles. Think of them as being either with
: wax, or without wax. Normally, polyester resin does not harden completely
: in the presence of air; it stays tacky, which is a nice feature when you
: are laminating many layers of glass and resin. The final coat of resin
: would have some wax dissolved in it. As the solvents evaporate and the
: polyester resins polymerize, the wax is pushed out of the mixture and ends
: up on the outside sealing the surface of the resin, excluding air, and
: allowing the resin to completely cure.

: You need to roughen up the surface slightly (just enough so it isn't shiny)
: so the epoxy will adhere nicely. If the polyester resin you used still
: feels tacky, then it probably did not contain wax, and trying to sand it
: will be a mess. Varnish it (use a cheap varnish) or coat it with a barrier
: of lacquer, shellac, paste wax, vaseline, saran wrap-- anything which will
: exclude air for a few days while the resin hardens. Then use solvents or
: sandpaper to remove all the sealing materials before you apply the epoxy.

: If the resin you used contained wax, then a light sanding will remove any
: surface residue and you are ready to go.

: Good luck with your building,

: PGJ

Thanks to everyone for their input.
I feel better and will exhibit and practice
patience!! ;) ha! Don't take my toys away!
The only place where the polyester is exposed to air is on the outer
surfaces of the panels. I'm going to sand those a little.
I'll deffinately glass the interior in the area around the but joints.

What a great resource this BBS is!!!!!!

Julie

Messages In This Thread

Epoxy: Epoxy over Polyester??????
Julie -- 11/3/2003, 4:03 pm
Should work great
Paul G. Jacobson -- 11/3/2003, 8:11 pm
Re: Should work great
Julie -- 11/4/2003, 11:36 am
Re: Epoxy: Polyester over Nothing
C. Fronzek -- 11/3/2003, 7:47 pm
Re: Epoxy: Epoxy over Polyester?????? *LINK*
srchr/gerald -- 11/3/2003, 5:30 pm
Re: Epoxy: Epoxy over Polyester??????
Paul Jacob -- 11/3/2003, 4:56 pm
Re: Epoxy: Epoxy over Polyester??????
ChrisO -- 11/3/2003, 4:19 pm