The Humpty Dumpty theory of osmosis treatment!

[Gerry]

Our Bowman 40 is currently being treated for osmosis. The gel coat has been sanded off and we are waiting for the moisture readings to drop. The contractor has now told us that while the original five coats of epoxy would be sufficient, ten coats would be better still and would mean he could extend his warranty from 5 years to 10.It reminds me of the line 'if all the kings horses and all the kings men can't put Humpty Dumpty together again that just shows we need more horses and more men!'
Will an extra 5 coats really make any difference at all?

 

[longjohnsilver]

Don't know. Will your contractor still be in business in 5 or 10 years time?

 

[Guest]

West systems told me (when doing my boat) that the "imperviousness" of the coating was proportional to its thickness. All coating are permiable to some extent, including epoxy. Thicker the better apparently.

Given the aggro involved in getting the boat ready for coating in the first place, I would be inclined to put extra coats on. The increased cost should be a lot less than 100%.

 

[toad]

See www.docksidereports.com for (depressing)reports on osmosis.

 

[Pandion]

Take a look at : http://www.hyab-osmocure.com/ and read why it might not matter how many coats of primer you use if the hull is not treated as it should be.

Jon Kolstoe
S/Y Pandion
Oslo

 

[Footpad]

Re: More Information Please

Went to the site as recomended, couldn't find anything on osmosis. Help please.

 

[andyball]

Re: More Information Please

http://www.yachtsurvey.com/BuyingBlisterBoat.htm is an interesting article on the subject....it may be the one you were suggested to read.

 

[Gerry]

thanks for the response. Very interesting reading on some of the sites you led me to.... Off to see the boat on Monday, have to make a decision then. Have to say the engineer in charge seems to know his stuff but at least now I can ask some seemingly intelligent questions!

 

[toad]

Re: More Information Please

Go to docksiders click on surveying fiberglass power boats then click yacht survey on line then blister index.

 

[johnt]

Im suprised that no-one has raised the point that UNPIGMENTED (i.e.clear) gelcoat is less susceptible to osmosis than pigmented gel coat ..my boat is 24 years old and unpigmented, the only place I have problems is the pigmented boot top !

On this basis ...why DO they pigment underwater gel coat these days ....you aint going to ever see it are you?....oh one thought though ....unpigmented shows up where the air pockets in the layup are!

 

[lezgar]

A gel coat never have to be sanded off. The problem will be much worst later.
Read www.yachtsurvey.com/blisterfail2.htm