Resins, Epoxy, Polyester, Repairs and Lamination

[mphatc]

I have a few questions, as materials have changed and technology improves . .

From other threads that some here are aware of, I'm in the midst of another boat restoration / renovation / rebuild. It happens to be a Magnum 27, 1968 Vintage.

Resins, when repairing an old boat, what kind of resin is the best to use for laminating and rebuilding a transom with new plywood to the old glass?

Is this the same that will create the greatest strength for the covering layers of glass over the new plywood?

Many years ago I worked for a Gordon Douglas Boat company that built the Flying Scot sailboat, layups were done over a period of days with slight grinding in between, recently I've read on this forum to do thick layup in one step? Which way is best?

Temperature and hardener. . . . epoxy , polyester . . . IRC . .
faster cures with more hardeners used to mean a weaker laminate . .
still true?

Resin Brands, are they different? In my world of high performance cars they must be like engine oils, where synthetics are more expensive, but brands are still different in quality.

Thanks,
Mario L.


Mario L.

[gcarter]

Mario, you need to decide how you're going to do the repairs.
Epoxy is the strongest, but it's difficult to paint over it, and gelling is impossible.
I personally only use epoxy for bonding where there's no exposure to visible surfaces, like ply to the transom glass, or under stringers.
I do use vinylester resin w/1708 Knytex double bias stitchmat that i purchased from Mertons in CT.
http://www.mertons.com/index.html
They offer Ashland vinylester resin and the Knytex stitchmat for the best prices I've found.
Vinylester resin and stitchmats will deliver only slightly less strength than epoxy and much better water resistance to osmotic blistering than polyester resin.
I know there's a lot of other opinions here, so I'll sit back and let them have it.

[Grinder]

Vinylester from Ashland great choice ventilation and personal protection is the key to long nontwitching life!

[RickR]

There is a wealth of info here
uscomposites.com
And here
http://www.boatdesign.net/forums/fiberglass-composite-boat-building/

[joseph m. hahnl]

I have a few questions, as materials have changed and technology improves . .

From other threads that some here are aware of, I'm in the midst of another boat restoration / renovation / rebuild. It happens to be a Magnum 27, 1968 Vintage.

Resins, when repairing an old boat, what kind of resin is the best to use for laminating and rebuilding a transom with new plywood to the old glass?

Is this the same that will create the greatest strength for the covering layers of glass over the new plywood?

Many years ago I worked for a Gordon Douglas Boat company that built the Flying Scot sailboat, layups were done over a period of days with slight grinding in between, recently I've read on this forum to do thick layup in one step? Which way is best?

Temperature and hardener. . . . epoxy , polyester . . . IRC . .
faster cures with more hardeners used to mean a weaker laminate . .
still true?

Resin Brands, are they different? In my world of high performance cars they must be like engine oils, where synthetics are more expensive, but brands are still different in quality.

Thanks,
Mario L.


Mario L.

PM Ginger.
OFFSHORE GINGER (http://www.donzi.net/forums/member.php?u=8137)
Registered User

http://www.donzi.net/forums/image.php?u=8137&dateline=1273174909 (http://www.donzi.net/forums/member.php?u=8137)


He will steer you in the right direction:yes:

[CHACHI]

Merton's fiberglass is in Springfirld,Ma.

Ken