On Jul 30, 9:21*pm, "Just wait a frekin' minute!"
wrote:
Frogwatch wrote:
On Jul 27, 7:01 pm, Paul Oman wrote:
Frogwatch wrote:
My three yr old Tolman 20' Standard Skiff has some serious epoxy
problems that cause me to doubt that this building method can work for
my N. FL conditions.
I built her with System 3 resin using the slow hardener due to the
heat here. *I used the metering pumps o get correct ratios and
followed the builders directions.
All went well *for the first two years but then got a separation of
epoxied wood at the transom. *This had been glued by first painting
the wood with epoxy followed by a thin layer of epoxy/fiber paste and
serious clamping. *I pried the two layers apart last year and re-
filled with epoxy thinking the problem solved (NOT).
Yesterday, I found the biax separating from the stringers, a long
piece that had been clamped to the gunwales and glued separating and
other places where the epoxy simply had not adhered to the wood. *I
will be able to use her for the next couple weeks (scallop season) but
this will require some major surgery.
Under N. FL humidity and rain, it is nearly impossible to keep her dry
and I suspect that swelling of the wood due to absorption of water is
the big problem.
I plan to remove all the rest of the expensive paint i put over the
original epoxy primer because it simply did not adhere anyway. *Then
will grind out the bad areas dry everything and try to re-glass the
bad areas after using a heat gun to dry them.
I would hesitate to use epoxy/glass over wood for another project here
in N. FL conditions.
doesn't sound right to me. Note that wood expands and contracts with *
moisture - epoxy and other things with temperature.
Might also be an amine blush issue *between the different coats of
epoxy. Also, most epoxies are brittle and cannot handle movement without
the reinforcement of fiberglass cloth. There are flexible epoxies to use
when painting...

Epoxy primer is just solvent thinned epoxy. If you covered your hull
with epoxy during building then it was already primed.
If you used a 2 part LPU coating you certainly needed an epoxy primer,
but your epoxy blushed, that would explain a few things.

Email me privately and I will get you a sample of our Basic No Blush
epoxy for you to evaulate.

So what did the MAS epoxy folks say?????

paul oman

progressive epoxy polymers incwww.epoxyproducts.com/marine.html

This is worse. *The biax glass actually cracked over the stringers and
the 8 oz glass cracked over the gunwales. *These are not high stress
areas but the stringers where it cracked does have a 1" radius of
curvature. *Note, these cracks and delams are in areas covered by
glass. *These are not normal use stress cracks but the epoxy
separating from the wood and the glass actually cracking afterward.
The epoxy primer is a 2 part material thinned with Isopropyle alchohol
to protect the epoxy from UV. *It works well and I will use it as my
finish coat from now on.
All of the areas appear to be areas where the epoxy simply did not
adhere to the wood well allowing the epoxied glass to flex and crack.
My issue now is how to fix the delams. *Do I simply inject epoxy and
drive screws to hold them till it sets or do I leave said screws in
place. *I worry future epoxy by itself will also fail.
In areas where the layers of biax separated from the stringers, do I
somehow make the biax layers adhere to said stringers or do I grind
away the old biax and replace it with fresh stuff.

It just sounds like you didn't prepare the wood properly. I use a
sawblade turned on it's side and scrape negative gashes into the wood to
produce a more mechanical bond than chemical. Also, you may have had
other problems with the laminating process, sometimes with Epoxy, more
is not necessarily better..

I intend to something similar when I re-glass the bad areas.