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  Topic Review (Newest First)
03-26-2013 09:21 AM
Re: bottom

We had 40 plus years of antifouling that we had to remove. ( looked very much like the above images )
This was applied to a 1964 grp 26 foot yacht.We know Both the previous owners they always scrapped off the loose and recoated .....

Click on page 3 for images PAGE 3

I ended up by using an electric hot air paint stripping gun and a FULL faced dust and Fume mask.

It took a long time to get off and then we sanded the whole of the bottom down with a 150 grit sandpaper.
It was one of them nasty jobs that just had to be done.

03-26-2013 07:08 AM
Re: bottom

You have basically the same deal as me... no blisters (well mine have been repaired before, and I have found 1 since)...

But basically if it had anti-fouling on it already at one point, then it likely has has barrier coat as well.

Scrape off all the anti-fouling (only if it's so bad that it's flaking off)... If you do this... do it all. Sand, 60 grit or 80 grit. Once smooth... use a wash to remove any mold release if you accidentally hit fiberglass removing the anti-fouling (trust me you will, lots).

Once that is done, fill the scratches, and gouges (there will be plenty)... fair the keel (make everything smooth-ish)... Then barrier coat. Then bottom paint.

The alternative (that I now STRONGLY recommend)... soda blast the bottom. Its quicker, and less labor for you! Even if you've never done it, the learning curve HAS to be better.

This is what I started with:

and this:

Fairing Compound:


Barrier Coated:

I've since VC17m'd the bottom (I'm freshwater).

But anyway, I have to say the Interlux 2000e Barrier coat is neat stuff. Hard as nails, auto-levels nicely, and is very thick/tough. Also I used interlux water tight for fairing (boy that stuff is a pain to sand).

EVERYTHING is toxic! Copper ablative, epoxy paints, bottom paints, sanding is especially bad. Use a lead paint removal (or better) respirator, and a bunny suit, gloves... the dust gets into everything!
03-26-2013 06:35 AM
Re: bottom

Owning a 40 year old boat can be a useful exercise in learning to accept imperfection.

Get out there and sail! Enjoy the beauty of sailing, not the drudgery of boat ownership.
03-25-2013 08:14 PM
Re: bottom

The barrier coat is intended o be a continuous membrane, so a patchwork approach probably won't fly unless you're repairing damaged parts of a previous barrier. In any event the barrier should not be applied over old anti fouling, I'm afraid.

If the bottom is blister free and it's just a matter of some spot fairing and sanding, then simply cleaning, painting as jw29 suggested may be all you need for now, and go sailing.
03-25-2013 08:02 PM
Re: bottom

Thank you all, This really helps

When i sand down my bottom to an even surface, is it no problem if there will still be some of the old antifouling remaining and i paint the barriercoat over that ? or should i maybe only apply new barriercoat to those areas that are exposed and/or going to be repaired and not where the old antifauling is still firmly enough attached to the hull that a bit of paint scraping and some sanding will remove it ?
03-25-2013 02:39 PM
Re: bottom

You might consider using a paint scraper to remove any peeling paint or chips, sand down bottom to a relatively even surface, apply bottom paint with roller and brush, and go sail your boat.

See how it looks next season. By then, you will have even less passion for a bottom job and will probably just do the same thing. Works for me!
03-25-2013 02:28 PM
Re: bottom

Antifouling paints should not be sprayed... very toxic and the solvents used are probably worse.

Topsides and decks are best painted with two part polyurethanes, nonskid applied with the various purpose-intended coatings like Kiwigrip will yield best results. Adding sand is an iffy proposition.. eventually the paint wears away and the dark sand is exposed.. rather unsightly after a while...
03-25-2013 02:02 PM
Re: bottom


Drying the exposed laminate can be helped dramatically by careful "washing" the spots/scratches/gouges with acetone. Acetone is very volatile and evaporates quickly. It is also very flammable so no smoking!. It is a great solvent because it will dissolve both oil and water the way alcohol does only better. If you have exposed laminate you suspect contains moisture, saturating it with acetone and letting the acetone dry (you can warm the surface with an electric heat gun or lamp if you are careful) will dissolve water and take it with it when it evaporates. It helps a lot. It is such a good solvent for fats and oils it will remove them from your skin, too if you let it wet your hands for prolonged periods. It also has the insidious ability to take molecules, that would other wise be too big, through semipermeable membranes (like skin). I use it a lot and have for decades. Chemists use it as a rinse for lab ware that needs to be dry and "chemically clean" (a high standard).

Put on some eye protection and some nitrile gloves, wet a clean rag with it and "sponge" the spots with the rag. Keep the rag wet with acetone. Get your target laminate saturated with it. You can tape a rag to a bad spot and keep it wet. It will "draw" the moisture out. It will also dissolve other stuff. Some plastics will dissolve in it. Your watch "crystal". Just keep it off anything you don't plan to remove. Some paints will soften, too.

I have a couple of gallons in my shop beside the alcohol, the xylene and the white kerosene. They are all dangerous chemicals but no more dangerous than gasoline so treat it with the same respect.

Good luck,

03-25-2013 10:02 AM
Re: bottom

Re fixing your bottom there is a really good guide here CLICKY

I would be VERY cautious about spraying polyester or vinylester gelcoat onto either topsides or decks as a refinish method. It has a VERY poor reputation as far as adhesion is concerned. Basically it does not bond to cured fibreglass. I have seen such a job where the applied gelcoat was coming off in sheets JUST weeks after the job was done [ and paid for ]
03-24-2013 11:23 PM
Re: bottom

Thanx, so no gelcoat under the waterline. And best not to start grinding non-damaged areas.

Barriercoat is normally only used under water right ?

I also want to redo the above water parts, (topsides, deck, cockpit) either with paint or with gelcoat. Above water, there is damage, but its rather minimal, a few tiny scratches that i will fill. Now i was thinking the gelcoat is both cheaper (30$ vs 100$ a galon) and stronger than paint and intended to apply that. Am i right or is gelcoat not a good idea ? I should have a spray gun available for either. I will also be including some antiskid in it. I am not yet entirely sure what that is gonna be. If i find a good product available for a reasonable price ill buy it, else i intent to use the finest sand i can find.
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