To epoxy or not to epoxy

[pkb]

When I bought my boat five years ago the good chaps at Ancasta arranged for her to be anti-fouled but they did so without first priming the hull. When she is out of the water this winter I plan to have the old antifouling stripped off back to the gelcoat.

Do I then just apply some primer to provide a good key for the new anti fouling.

Or is there an advantage in having the gel grit blasted and then having epoxy applied. I know a couple of people who have gone down this route but I have to admit I haven't properly understood the logic.

My thinking is towards just priming the hull - I have to say I am slightly nervous about having a perfectly good gel coat deliberately "roughed up".

I would welcome advice or views on the subject.

Peter

 

[andy_wilson]

Missed opportunity

When I bought my baot she had been out of the water for a year, including some time under cover. As I planned to keep her afloat for a year or two, I decided to strip off the anti-fouling that was ready to go, and have her epoxied, despite of a spotless bum, and no sign of problems.

This was heartily endorsed by my surveyor.

If you haul out every year, and there is no sign of a problem, why bother. If the answer to the above is not so positive, there will never be a better time than when you are stripping the hull anyway.

The roughing up is marginal, and lost material is more than replaced by an even tougher epoxy layer.

 

[vyv_cox]

The truth is that no coating is 100% impervious to water. Iso-phthalic gelcoats are better than older ones, but water will eventually diffuse through. Epoxy coatings may be (I don't know) better than gelcoat, but they will ultimately let water through. My Gelshield 200 coating lasted 10 years but then the hull blistered a little. Anything you can do to delay the almost inevitable will help. So I would apply Gelshield 200, it's no more difficult than anti-fouling anyway and will cost about 70 - 100 pounds for three to four coats on a 35 ft boat.

 

[Twister_Ken]

\"Hull Epoxied\" ...

... seems to feature often in boat ads, so whatever the pro&cons re osmosis maybe it helps sell boats more quickly, or at a better price.

 

[oldsaltoz]

G'day Peter,
We had blisters and did the epoxy treatment, only time will tell how good a job it was.

The interesting point here is that the paint manufacturer, (International), advised us to apply the first coat of antifouling before the last coat of hull protective paint was dry; this they advised provides a very good key for the subsequent coats prior to launching. Perhaps you should ask your supplier if this is ok, as it's not suitable for all paint types / manufacturers. Also a good practice to stick with one brand when doing this type of work.

Also note that damage to your existing gelcoat will depend on the experience of the operator, it's a good practice to attend the blasting operation.

Hope this helps.

Avagoodweekend______Old Salt Oz....../forums/images/icons/cool.gif

 

[FlyingSpud]

Does that mean that really what we should do is epoxy every 8 years or so?

 

[vyv_cox]

International don't print any information to this effect, but when talking to their representatives this is the gist of what they tell you. Problem is, once you've put the stuff on the hull it's very difficult to get the water back out through it. Hence last winter we stripped right back to the Gelshield and then sanded it off as far as possible. Left the wind to blow around it for a couple of months, then back on with new Gelshield. As a post above says, International recommend a coat of hard A/F before the Gelshield has cured to give a good base for subsequent A/F.