Epoxy resin the hull?

[Jacqueline]

I am in the process of scraping off many old layers of anti foul in order to put 4 coats of epoxy resin on the hull and thereby avoid the danger of osmosis. (This was something the surveyor recommended when I bought my boat last year).

However Mario from the boat yard said it is a waste of time and effort because when I come to antifoul the primer is made of epoxy anyway and two coats of that should suffice.

Can anyone comment?

Also I am sanding the hull with rough sandpaper and I want to know if I have to go over it again with smoother sandpaper and if so why?

Would be grateful for any help.:thumbsup:

 

[Henry Boyd]

Besides the obvious, one of the benefits of anti-fouling paint is that it seals the hull from water incursion. I can't comment on whether the anti-fouling paint on your boat contains epoxy, or not. There are many formulations of anti-fouling.

Removing all of the bottom paint is a difficult task. Sanding it off is about the worst way to do it as it not only is dirty and hard work, but also puts the person sanding at a serious health risk. Bottom paint is for killing marine life, so it can't be good for land animals to be breathing the dust , right? Even if you do not have health and safety workplace regulations where you are that regulate this kind of thing, bottom paint dust is bad for people.

The best and safest ways to completely remove bottom paint are either a chemical treatment, or by blasting using an abrasive appropriate for a fiberglass structure. That may sound like a contradiction to my earlier comment, but people who do this kind of work wear safety equipment and will often tent the area being worked on to contain the dust.

Unless you really want to go to bare hull and start over, you don't have to remove all of the bottom paint for normal service, or annual repainting. If you are sanding and finding it hard to get the old paint off, that is good because all you have to do is scuff the old paint (not remove it to bare hull) and paint over it with new paint.

Henry

 

[tobnpr]

Besides the obvious, one of the benefits of anti-fouling paint is that it seals the hull from water incursion.

This isn't true.
Antifouling paints, even the "hard" modified epoxy paints, do not prevent moisture from migrating into the gelcoat.

If they did, there would never be the need to barrier coat a hull.

When your surveyor said to "epoxy coat" the hull, and the yard guy said the "primer" is epoxy anyway- I think they were both referring to the same product- an epoxy barrier coat. The most widely used is Interlux Interprotect:

http://www.yachtpaint.com/USA/hotlinks/interprotect_bulletin.pdf

 

[Lazy Daze]

Another thought on this...

Did the surveyor actually find evidence of moisture? Or, was he simply saying "it'd be a good idea"? If there was no evidence of this on an 18 year old boat, just keep doing (and using) whatever the previous owner was doing. Keep it simple, you know?

If there was evidence, I'll second Henry's recommendation on hiring someone to do it for you.. for every reason he mentioned.... especially how much of a PIA it is to do! Check out "soda blasting".

 

[wkearney99]

I'll second Henry's recommendation on hiring someone to do it for you.. for every reason he mentioned.... especially how much of a PIA it is to do! Check out "soda blasting".

I'll third that. I paid to have mine soda blasted. They setup a tent under the whole boat and then went in wearing a full body suit with a hookup to an external ventilator. Had the whole thing blasted in under an hour. That and they took it all away with them. I seem to recall it was around a grand for the job.