But Steve ...if you recall that polyester is semi-permeable, then putting it
on one side of good dry wood sounds like it would work, no? The dry wood
will give it the best bond it can get, and then later when the boat's in use
water that's absorbed in the wood and glass has a way to escape. If the
structure of the boat doesn't allow too much expansion (as in plywood), then
I don't think the poly bond would suffer too quickly. Epoxy glass would
tend to collect the water at the epoxy/glass-to-wood interface. The initial
bond would be better, but I would guess that a one-side epoxy glassing would
be more prone to rot than a one-side polyester glassing. Epoxy *is* far
better, but you do have to keep it sealed up. Some of the finest wood boats
available, such as Huckins yachts for example, are epoxy glass on plywood
....and sealed on all sides of all wood. As far as toxic substances go,
maybe that fellow who made the remark should read a few MSDS's. I have a
feeling he's going on rumor more than fact on that one.

Brian

"steveJ" wrote in message
...
I visited a boat shop on Grand Manan Island in the Bay of Fundy
two years ago and my observations would lead me to believe that
what you say about polyester not sticking to wood is incorrect.
This shop built and refurbished commercial lobster boats up to about
40 feet in length. At first I had my doubts. The owner, a great old guy
in his 80's, showed me a traditionally planked boat that he had
polyester fiberglassed over about 15 years prior. The boat was made from
white cedar and white oak and much of the trim was maple.
The boat was still in good shape, no rot, except for the maple trim
pieces which were above the waterline.
This boat was fiberglassed only on the outside. The interior was bare
wood with some areas painted. This boat was being heavily used as a
commercial lobster boat. The boat was back in his shop to replace
the outer rubrails and gunnel trim and to put in a polyester patch
that had worn through where they dragged the traps up over the side.
He explained that the trick was to dry out the wood throughly.
This shop had a heated concrete slab floor.
I asked him about epoxy and he said he would not allow it in his shop
because it was toxic.
Being a long time advocate of the wonders of epoxy I was very surprized
to see all of this but it is hard to argue with reality. Especially when
you see it from people who depend on the materials for thier lives.
Perhaps they were successful using polyester on wood because of the cold
water temperatures and salty water. I don't know, except in this case it
worked.

Another Steve
SteveJ

Le Grande Raoul wrote:
In article , steve
wrote:


Rufus wrote in message
news:8wcCb.510431$Tr4.1423564@attbi_s03...

There are two intrinsic problems as I understand it. 1) The glass will
delaminate from the wood, one way or another. 2) Moisture will get into
the wood from the inside and the wood will stay wet and rot (because
the
bottom is sealed).

I have never had any delamination or wet rot problems as you
described.


This "won't stick" idea comes from the days before epoxy was available
at reasonable prices. Polyester doesn't stick to bare wood very well.
It does relativly well when the wood is new but pretty bad if the wood
is used. Once read in a book that if one wants polyester soaked glass
to stay attached to used wood, it needs to be mechanically fastened
(nailed).

Modern epoxy does very much better and an entire new style of
boatbuilding erupted when it became financially feasable.

Jeff

On Sun, 04 Jan 2004 01:51:11 GMT, "Brian D"
wrote:
//// As far as toxic substances go,
maybe that fellow who made the remark should read a few MSDS's. I have a
feeling he's going on rumor more than fact on that one.

Brian

Sadly, many people have developed extreme sensitivity to epoxy resins
after less than proplonged exposure while building projects.
They have to swear off the stuff, thereafter,

Brian W

Wow -

There is a lot going on here.

If you read all the MSDS (I have had to do so), Epoxy is less toxic
than polyester, and as it does not outgas in curing (notice - no new
epoxy smell?). The exposure sensitivity can and does happen with almost
anything.

I have seem a number of hulls that were glassed after some service time.
bond failures are common.

If you use a thin polyester resin on new-clean wood, you have a chance.
The builders that went that way also did not caulk the seams. I know
of few that a few working boats and a couple of Tahoe Chriscraft that
are still in great shape. But, there is a secondary problem with
replacing a broken strake or frame.

When you consider that the life of a typical wood hull was twenty years,
you begin to realize that a lot has change in th life of people in my world.

Matt Colie - Lifelong Waterman, Licensed Mariner and Pathological Sailor
www.southpointechandler.com



Brian Whatcott wrote:
On Sun, 04 Jan 2004 01:51:11 GMT, "Brian D"
wrote:

//// As far as toxic substances go,
maybe that fellow who made the remark should read a few MSDS's. I have a
feeling he's going on rumor more than fact on that one.

Brian


Sadly, many people have developed extreme sensitivity to epoxy resins
after less than proplonged exposure while building projects.
They have to swear off the stuff, thereafter,

Brian W

matt colie wrote in message ...
Wow -

There is a lot going on here.

If you read all the MSDS (I have had to do so), Epoxy is less toxic
than polyester, and as it does not outgas in curing (notice - no new
epoxy smell?). The exposure sensitivity can and does happen with almost
anything.

When I was 20 I began rebuilding an airplane using epoxy glues.
After a year of part-time work on the project, and getting the stuff
on my skin, I had to abandon the epoxy and go to urea-formaldehyde. My
eyelids would swell up just in the presence of epoxy curing, and my
immune system got all screwed up and I became allergic to a range of
things like milk, many pollens and dust. 30 years later I still suffer
the effects and have to be really careful around any epoxies.
On the other hand, I have worked extensively with polyester
resins and had no trouble at all.
On the subject of polyester vs. epoxy, I have found that
polyester won't cure if applied over an old epoxied surface. Stays
gummy. Had to scrape it off and remove all the old epoxy, then
re-glass it.

Dan