Page 1 of 1
that old osmosis thing
Posted: Thu Oct 30, 2003 12:13 pm
by pedro
Hello
I have just had a boat surveyed. Report says it has two large blisters (category 2 scale 1-3) . They are about 6 " in diameter. One either side of the hull about 14 way back from the bow. The surveyor reckons they can be fixed. While I do not doubt they can be fixed. Anyone had these sort of things done and how much did it coast and after they are fixed is the resale value back up to as if you never had them?
Any comments welcome
Posted: Sun Dec 14, 2003 2:30 pm
by alienzdive
check with litmus paper, if it is alkalai it is osmosis,
blistering is common on fibreglass boats built around 20 years ago.
just grind them back to a solid surface, not much more than the blister area, fill with an epoxy filler, prime and undercoat with an epoxy type paint, then antifoul as normal. Usually if you take it to a marine painting company they "(should not)" charge any more to fix the blistering on top of the cost of antifouling.
It is unlikely to be osmosis due to the size of the blister.
It is probably caused by an inconsistency in the glue mixture during construction.
Re: that old osmosis thing
Posted: Sun Sep 06, 2009 4:51 pm
by sailman
Some information here at east coast fibreglass supplies
http://www.ecfibreglasssupplies.co.uk" onclick="window.open(this.href);return false; if you look here in the west user guides they is section on osmosis / blister repair
http://www.ecfibreglasssupplies.co.uk/s ... isters.pdf" onclick="window.open(this.href);return false;
good luck!
Re: that old osmosis thing
Posted: Sun Sep 06, 2009 5:16 pm
by Mark
Go the Library and get 'Fibre Glass Boats' by Hugo de Plessis. An evening reading that will tell you everyhing you need to know. (And probably set your mind totally at rest)
Re: that old osmosis thing
Posted: Sun Sep 06, 2009 6:11 pm
by Silkie
Suspect the OP has probably sorted these out by now.
Given that this is his first (dredged up) post I suspect also that the dredger is a purveyor of canned meat products.

Re: that old osmosis thing
Posted: Mon Sep 07, 2009 7:04 pm
by Nick
Given that this is his first (dredged up) post I suspect also that the dredger is a purveyor of canned meat products.
East Coast Fibreglass is a BlueMoment advertiser (
Boatbuilding section) and as such I have no problem with this post at all, particularly as the yearly bill will be going out next week
In fact, it would be nice if more of our advertisers posted on here as I am sure they have a lot of knowledge they could share with us.
Welcome aboard Sailman.
Re: that old osmosis thing
Posted: Tue Sep 08, 2009 9:22 pm
by little boy blue
can i just add a wee plug for the east coaster as well. had excellent advice and service from them earlier this year. ( no other connection etc ).