Osmosis treatment - anyone experience?

[GilesC]

I need some advice. I've just been told I've got some osmosis on my 20 yr old gibsea, and it will need sorting out in the next 2 to 3 years. I've actually been through the whole process before with an old Jaguar, and although the end result was good, I was only really prepared to risk a DIY job as the boat wasn't worth enough to warrant a professional job.

So question is has anyone had a professional job done, and how long did it last? Is it so superior to DIY that its silly to risk a DIY job on a decent boat? I'm not keen to do it myself again, but with a quote for £4000, I'm seriously thinking about it.

 

[oldsaltoz]

G'Day GilesC (with a very thin profile),

Like you I did my own Osmosis treatment some years ago, Bloomin hard work, but the end result was well worth it, and as this was some years ago and not even a hint of problem since, I'm glad I did it. Saved a fortune and learned a bit, now that can't be all bad.

As the 'Professionals' have to provide some sort of warranty, your quote will no doubt include some hidden charge by them in case you (or others) have a come back.

They, (The Professionals) also tend to vary in their approach to the work, some go overboard to ensure and no come back and charge heaps, others charge the same but do a lot less and get more come backs.

At least if you DIY you control the quality and extent of works.

I hope this helps

Avagoodnewyear Old Salt Oz /forums/images/icons/cool.gif

 

[Neal]

before throwing money and /or effoert at it...

speak to the technical departments at Blakes and International. They are extremely helpful, and they may well tell that you do not have to do anything yet.

When you say your boat has 'osmosis', what exactly are the syptoms.

 

[Guest]

I understand that the correct treatment for Osmosis that has taken hold is to peel of the gelcoat, steam a few time to clean, allow some months to dry out properly and then apply Gelshield- a job for professionals! Very expensive and from what I can gather, not guaranteed to last! Our Princess 33 has Osmosis but at the surveyors advice we bought her very reasonably and will have the treatment done in 3 - 5 years when it fully warrants it. We don't want to be doing it again before we sell her.

 

[Guest]

I did a DIY job on a 34ft boat. Great results so far.
A friend had his done by Moody's. He said they did a terrific. job. When the boat came out a year later there were a couple of bubbles but they remedied these with the same level of service without question.

I believe 'drying out' is the most important part. I personaly have doubts about companies that offer drying with a heat gun etc. It takes a very long time to extract moisture and this method cannot in my opinion be effective. Another friend of ours just had his Westerley done in Wales. It was significantly cheaper for him to have the yacht hauled out and transported to Wales. I don't know which yard did it but he was full of their praises.

 

[Guest]

since you are already familiar with what is involved, there are only two issues to consider in deciding whether or not to diy. firstly the effect on re-sale value of a diy job and the absence of a gttee. could possibly get round this by caughing up for a surveyor to specify the work and to confirm it was done. the second issue to balance against this is the likelyhood of getting a yard employee to do half as careful and thorough job as you would do.

suspect the selling price of a diy treated boat without gttee would be that of a yard treated gtteed boat less the cost of a re-treat. i would try that negotiating line if i were buying.

 

[jonjo]

If a specialist GRP surveyor has said you can wait up to 3 years before treatment I would be tempted to wait that full period because by then the new hotvac system will have had longer to prove itself.

Other comments:

Be suspicious of a specialist center that says it can get you back in the water within 5 weeks, from what I hear a combination of months of air drying + finishing with HotVac is the current best drying practice.

You could go for a hybrid solution, i.e. get a visiting pro to peel and blast, then a d.i.y. wash and long air dry in a polyethylene hull skirt. Finally a d.i.y. recoat in perfect mid summer conditions. All this probably means missing a full season.

 

[jimboaw]

Whats the problem? You want to sell the boat? or do you want to keep it?If you intend to keep the boat for the forseable future why worry? A few blisters are not going to make much of a difference in your hull speed. (in fact they may even help) Your surveyor will tell you to fix it before you put it on the market .From all I have discovered it would seem drying time is of the essence

 

[vyv_cox]

My boat came with a three-year guarantee, following professional treatment for the prevention of osmosis after a survey found high water content. Some seven years later there were evident blisters, so last winter we hauled out to strip and repair. We found that a maximum of two coats of Gelshield 200 had been applied in the professional treatment. After discussing with International we followed their advice to re-Gelshield 200 ourselves, applying 4 or 5 coats.

It could be that to strip, dry and apply Gelshield would give longer protection than our seven or eight years achieved but at a cost of thousands of pounds. Our application of Gelshield 200 cost less than 100 pounds plus lots of physical work. On a sliding scale of coats per year, we might expect ten years before more problems, especially as we shall leave fresh water berthing this year. In ten years time I expect to be in a much warmer place, where osmosis treatment is considerably cheaper.

As someone else has said, it depends on your aims. If the idea is to maximise value for sale, it might pay off to have the job done first and ask a very high price. If your intention is to keep the boat then DIY. Very few, if any, boats ever sunk due to osmosis, especially after some sort of protection treatment.

 

[jonjo]

Did these two successive rounds of osmosis work involve removal of gel coat?

If so it is interesting that you have found an economic formula for minimising osmosis over time that does not involve radical peeling and blasting.

I thought knowingly locking in under gel coat moisture behind an extra epoxy coat was asking for trouble.

 

[vyv_cox]

Gelshield is the replacement for gel coat that involves peeling or blasting the existing layer. Gelshield 200 is a solvent-containing epoxy paint that goes on top of the gelcoat.

It would seem to be necessary to remove moisture from the gelcoat prior to applying the Gelshield 200. Various opinions seem to exist about the need for this and the extent to which it is required. International told me that three months of winter wind blowing over the cleaned-off hull would be sufficient, so that's what I did. No doubt plenty of yards wanting to sell you their services would disagree.

 

[GilesC]

Good afternoon, Sir. Jolly nice to hear from you, old chap.
(well if you're going to be a stereotypical aussie, with your "g'day", the least I can do is keep to the sterotyical pommie!)

Anyway. I've had some insults in my time, but no one's every accused me of having a flat profile before! What's that mean? Am I meant to have filled something in to give away my inner-most secrets? Never was much good with this technology stuff.

As for the osmosis, I'm coming round to the DIY point of view again, though with much hesitation - I remember the las job too well. Still that was on a lift keeker only about 2 foot off the ground, so this should be easy on a deep fin! Well maybe not that easy. I had been thinking about selling the boat, and hence getting the job done properly, but having seen whats out there in my price range, I'm rapidly changing my mind! Given the quote for £4k to get it done properly, its got to be worth a few aches and pains.

Cheers

Giles

 

[oldsaltoz]

Goodonyer Giles,

Great to see you filled in your profile, now we know what you have we can better answer your questions.

I know it's a hard work but at least if you do it yourself you 'know' just how well the job was done.

By the way, I had an old chair under my fin keeler, found it very handy when sanding overhead, even considered making some modifications to lay it back and make the height adjustable.

Avagoodweekend Old Salt Oz /forums/images/icons/cool.gif

 

[jonjo]

Thanks for the reply, I will recount your experience to a surveyor next week and see if he accepts there is more than one viable strategy for dealing with the osmosis threat during an extended period of ownership.

By the way sorry for my confusing post above, I meant to say if you had *not* removed the gel coat during pervious treatment then your success is interesting.

The problem with a full professional osmosis job is that is starts with a destructive process, so what is the point if they skimp 50% on the re layering stage!

 

[mayfox]

Hello, Giles,

Could you let me know if my cheque has arrived for the Echo Sounder.

Many thanks,

Paul (mayfox)

paulthfc@msn.com

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