OSMOSIS ?

[rivonia]

Hi, our frind has his old boat on the hard and has one or two blisters. He has asked me to find out if his system to treat it is correct.

1 burst blisters

2 wash with fresh water

3 gently dry with hair dryer/sun for couple of days ( he has to get back into the water very soon)

4 sand area and clean again

5 fill with epoxy

6 sand and clean again

7 apply anti-foul

I said I would find out he is a lot older than me and has no computer.

 

[cliff]

1 burst blisters
1a) Remove gel coat in vicinity of blister (~3" all round)
2 wash with fresh water
2a) Repeat daily for 90 days
3 gently dry with hair dryer/sun for couple of days ( he has to get back into the water very soon)

4 sand area and clean again

5 fill with epoxy

6 sand and clean again

7 apply anti-foul

 

[rivonia]

1 burst blisters
1a) Remove gel coat in vicinity of blister (~3" all round)
2 wash with fresh water
2a) Repeat daily for 90 days
3 gently dry with hair dryer/sun for couple of days ( he has to get back into the water very soon)

4 sand area and clean again

5 fill with epoxy

6 sand and clean again

7 apply anti-foul

The poor old soul cannot afford to stay out 90 days or even a fortnight.

 

[Deleted member 36384]

His solution is OK from my understanding but it's a cosmetic fix only.

 

[Alan ashore]

There is a case for leaving them alone, if a full treatment, which certainly cannot be done over few days is not viable.

 

[jwilson]

There is a case for leaving them alone, if a full treatment, which certainly cannot be done over few days is not viable.

I disagree, a localised fix a la OP's suggestion is better than no fix. I'd open the blisters, and grind away maybe a quarter inch past the blister edge, then hot wash, dry, a couple of times, then epoxy fill. Cliff's option is certainly better, but it's an old boat, and this will hold the situation as far as those blisters are concerned for quite a few years. There will be more next year or in a few years time, but very probably in different places.

 

[rivonia]

Well from what you all have advised and from my searches on GOOGLE (not very helpfull) I shall pass on the advice and tell him to proceed. And thanks for the tip to use HOT WATER. He will have to put the kettle on.

Any other tips will also be passed on.

Many thanks

 

[TradewindSailor]

How can anyone advise on this without seeing the boat? Is it solid GRP or has it got a core? What does he use the boat for? Are the one or two blisters an accurate observation? What size are the blisters? What's in the blisters? How deep are the blisters?

Certainly any method that does not properly clean and dry the underlying laminate is going to be cosmetic only. If the one or two blisters is an accurate description of the condition I would rather suspect that he would be better off ignoring them, but it really needs someone knowledgeable to actually see what the problem is.

 

[rivonia]

The old man has ground them out and washed them with HOT water- done all that was asked. he will be filling in with EPOXY tomorrow.

He is thankful (his words) for the advice and tips.

 

[superheat6k]

Good for him - likely the hull will see us all out before osmosis makes this or virtually any other boat sink. The only thing mild osmotic blistering affects (as it is generally the case in the vast majority of cases where it is 'diagnosed') is sale value / ability. 'Osmosis' nautical term for boat surveyor talking bo110cks