Fibreglass sheathing required for large schooner in Lesvos, Greece

[aqfishing]

Originally Posted by s/v Jedi

What is wrong is that it was bad. Polyester simply is the wrong resin and chopped strands … I dunno, tell me what good it does?

Keeps the water out?

Did not say it was the best, but since the other 80% is poly with chop and its been there 20 odd years, why change?

[Benz]

Originally Posted by aqfishing

Keeps the water out?

Did not say it was the best, but since the other 80% is poly with chop and its been there 20 odd years, why change?

Because if one area failed, inevitably others will.
I for one don't like the chances of anything sticking to diesel-soaked wood--I think it's a dodgy situation, but I guess the best has to be made of what there is.
Given that the rest is poly/chop, I wonder why we're talking about complicated multi-axial laminate schedules, when the OP may be limited to what's available in Lesvos.

[Fore and Aft]

Benz I was wondering the same thing when reading this thread. I was thinking maybe Vinylester and whatever cloth is on special to make up the laminate. The original laminate sounds nothing special.
Cheers

[Boatwright]

I've seen more than one fixer-upper, fiberglass over wood job that ended up abandoned in the back corner of the yard.

I really like the SS staple idea. This avoids the problem of trying to pre-wet or bag the job when working overhead. Bagging requires a large, experienced crew working fast and is very unforgiving. With the cloth stapled, resin can be mixed and applied in small well-controlled batches -- no thermal runaway, etc..

I wouldn't worry too much about the weight issue in a hull this large.

I got involved in a "charity" job a few years ago, which ended with a bunch of unqualified amateurs doing their best to ruin things. I finally had to say no, not worth it. The boat is now for sale with no takers....

Good luck.

[aqfishing]

Originally Posted by Benz

Because if one area failed, inevitably others will.
I for one don't like the chances of anything sticking to diesel-soaked wood--I think it's a dodgy situation, but I guess the best has to be made of what there is.
Given that the rest is poly/chop, I wonder why we're talking about complicated multi-axial laminate schedules, when the OP may be limited to what's available in Lesvos.

It seem those areas failed for good reason. Would epoxy have made a difference in the same circumstance?

[Matt Johnson]

Regarding staples: The higher-end strip planking builders use composite staples - Raptor is one brand - that way you don't have to worry about corrosion and expansion of rust anywhere in the laminate.

[s/v Jedi]

Staples aren’t needed for this. Just use some 3M 77 spray glue to hold it in place, then wet it out with a roller.

[Benz]

Originally Posted by aqfishing

It seem those areas failed for good reason. Would epoxy have made a difference in the same circumstance?

My bet is that diesel soaking through wood would be able to lift just about any coating, just like the grease that percolates though skin lifts even awlgrip off my leg where I leaned against it by accident, even if it takes a while.
I recently repaired an old fiberglass boat where oil and diesel in the bilge had percolated into the laminate and somehow leached all the resin out. It was all soft in one spot, and you could almost put your finger through. Dunno how epoxy would have done, but my concern here is initial sticking.

[fourlyons]

Except that fiberglass is a proven material for diesel fuel tanks. My understanding is alcohol/methanol however can dissolve the resin in fiberglass.
I think the failure on this schooner is more likely due to the fact that polyester resin is fairly weak as an adhesive.

[s/v Jedi]

Originally Posted by fourlyons

Except that fiberglass is a proven material for diesel fuel tanks. My understanding is alcohol/methanol however can dissolve the resin in fiberglass.
I think the failure on this schooner is more likely due to the fact that polyester resin is fairly weak as an adhesive.

Exactly. Funny how subjects where facts are commonly available become discussions about bets, gut feelings, opinions etc. like if the real world doesn’t exist

[aqfishing]

Originally Posted by s/v Jedi

Exactly. Funny how subjects where facts are commonly available become discussions about bets, gut feelings, opinions etc. like if the real world doesn’t exist

No one said the diesel dissolves the resin or fibre

Its about outer skin bonding or remaining bonded to the wood. If the wood fibres are compromised or become compromised over time, there is nothing that will bond to it…and thats the real world!

[aqfishing]

Originally Posted by fourlyons

Except that fiberglass is a proven material for diesel fuel tanks. My understanding is alcohol/methanol however can dissolve the resin in fiberglass.
I think the failure on this schooner is more likely due to the fact that polyester resin is fairly weak as an adhesive.

Diesel tanks are made with different resin/additive/flow coat lining. They do differ slightly. I know when we glassed the inside of our steel diesel tanks they used a different resin or additive to the resin and or final flow coat. Was awhile ago, so cannot remember exactly.

[s/v Jedi]

Originally Posted by aqfishing

No one said the diesel dissolves the resin or fibre

Its about outer skin bonding or remaining bonded to the wood. If the wood fibres are compromised or become compromised over time, there is nothing that will bond to it…and thats the real world!

You ought to read comment #38 again…

[Bowdrie]

You gotta start somewhere, and the best place to start is to get this book.
I read this when it was first published, and while some of the info may seem dated there is much to be gleaned.
https://www.amazon.com/Covering-Wood.../dp/0877421374