Bottom Paint

colbysmith · Posted: Thu Apr 01, 2021 9:18 pm Post subject:

So John and Bob, what you are saying is if I'm going with the Hydrocoat, I should stick with the regular stuff. The stuff with the copper in it. That's fine by me as it's about half the cost of the ECO stuff. I had no intentions of painting any part of the engine or brackets. Or the trim tabs. I was just going to repaint the hull, after I do a good job of pressure washing and then scraping any other old flakey stuff that doesn't come off. Since the bottom is black underneath the blue bottom paint, I have to assume that perhaps there was already some sort of sealant or primer put on initially. It's the top coat that tends to flake off. I can't remember what it was, but when I bought the boat the previous owner had some left in the can, and I recoated it soon after bringing it home. Looked nice for about a week. Then after some boating and washing with the pressure washer, it started looking bad again as the stuff flaked off. This time I plan to take a little more time in the preparation. Maybe give it more time to dry before launching again as well. If I get to it and we get a number of nice days during April, ideally I would be ready to recoat before the last week of April. Our next trip is planned for May 12th, so it'd have plenty of time to dry. Somewhere I read that some locations are prohibiting boats with copper bottom paints. Has anyone had a problem with that? Or is it primarily they won't allow one to paint with the copper based bottom paints? Also, with the Hydrocoat, will one coat of paint be enough, or does it require several coats? And am I off base in my thinking that I can get by with one gallon of paint?

gulfcoast john · Posted: Thu Apr 01, 2021 9:39 pm Post subject:

OK, I agree, no copper based paint on any aluminum bracket or outdrive, ever!

1 gal covers the TC255, in two coats outside 1 coat inside, so should be fine for your boat.

Not aware of anyplace banning Pettit HC bottom paint.

John

thataway · Posted: Thu Apr 01, 2021 9:49 pm Post subject:

Colby,
You really want to get as much of the old paint off. Use the highest pressure you can get with a domestic pressure washer. I have used some industrial ones in shipyards which will actually cut into any blisters (not that you will have blisters)

You would have the colored gel coat, then a barrier coat of epoxy, and various colors of bottom paint. Don't assume that you have a barrier coat of epoxy. The way you use the boat it is not necessary. Don't try and put epoxy barrier on, unless every bit of old bottom paint is removed.

colbysmith · Posted: Mon Apr 05, 2021 8:46 pm Post subject:

Started pressure washing much of the old bottom paint off the other day. Plans are to follow Pettit's instructions to sand with 80 grit sandpaper once I'm done pressure washing what I can get off that way. And I've already bought a gallon of the Pettit Hydrocoat (standard) paint. I did find the old paint can of what was on the boat, when I was looking around my basement for something else. Turns out the old stuff was Mar Pro Superkote Ocean Hard Modified Epoxy. From the price on the can, compared to what I paid for the Hydrocoat, and from other pricings I'm seeing, I'll assume the Mar Pro isn't too top of the line. Anyway, I plan to make this April's project during our warmer days. Hopefully with the proper preparation, the new bottom paint will adhere better and last a while. As I pressure wash much of the old bottom paint off, it appears that it may have just been put on over the original gel coat. However, there are areas that appear to have a black paint, so I'm assuming maybe that was the initial layer of bottom paint. Colby

gulfcoast john · Posted: Mon Apr 05, 2021 9:26 pm Post subject:

Colby,

Re-read Bob's second line three times!

Can you tell from the Mar Cote Epoxy can what color it was, so you can avoid blasting off too much of that (unless it's flaking)?

Green Scotch scrub pads are cheaper than 50g sandpaper and also rec'd by Pettit.

1 gal of 40% copper Pettit HC is too heavy for a commercial paint shaker. See the can instructions on buying an empty 1 g can from Lowes and a 5g stirrer for your AC drill to mix this.

You're on the way!

Best,

John

thataway · Posted: Mon Apr 05, 2021 9:52 pm Post subject:

Colby the MarPro is probably a 45% Cuprous Oxide modified epoxy solids--which makes it a 'hard" bottom paint. MarPro makes an epoxy barrier coat, but the can would indicate it was a 2 part epoxy. There is also a primer which MarPro recommends before the antifouling paint.

With this coming off fairly easily it suggests that no barrier coat was used, and that the primer may not have been used either. It will be in your best interest to get down to the gel coat.

Certainly you do want to use either a pad or sand paper for the prep...Be careful, I would not do any dry sanding. Be sure an wear proper gear (which I am sure that you are doing).

colbysmith · Posted: Mon Apr 05, 2021 10:01 pm Post subject:

colbysmith · Posted: Mon Apr 05, 2021 10:14 pm Post subject:

thataway · Posted: Mon Apr 05, 2021 10:56 pm Post subject:

If epoxy solids bottom paint is solid you can put either a hard or soft (stuffing) bottom paint over it. The sides are more likely to have been built up, and also flake as you see. They will normally have many more coats of paint. (As you did by putting another coat on, the way we use our boats (I do the same). But the soft paints wear away and you don't have to sand.

The dry sanding is potentially a health hazard. Full suit, hood, gloves and full face respirator, with a powerful shop vac, and "dry wall filter" (the usual paper and foam filters will not filter out the Cu oxide. There are special sander vacs used at the shipyards. Also many boats are soda or "media" blasted. Sandblasting has some substantial risks.

There is the alternative of using a chemical stripper. By the way, there is a "fake" MEK which may not have the solvent properties you desire. I needed some for the HH66 solvent glue--the synthetic didn't work--you need the real thing. Nothing works except the real MEK>

colbysmith · Posted: Mon Apr 05, 2021 11:20 pm Post subject:

Thanks again Bob for the advice and information. I've got the real deal in the MEK. Used it to put some new D rings on my Kayaks, after catching Rosanne's Kayak on that sign post abeam the large dock at Ed Stone (side tied with the crowd of incoming boats) and tearing off the bow handle I had my tow line on... Rolling Eyes

The HH66 with the MEK prep seems to provide a strong bond!
I thought about using my sandblaster, but not ideal laying under the boat using it. I have a couple of trouble spots on the very bottom of the hull, and other than that, depending on what happens when I start blasting it with my pressure washer, I may be able to leave most of it alone and just wipe it down well with the scotch pads and some MEK to prep it. Colby

colbysmith · Posted: Tue Apr 06, 2021 1:26 pm Post subject:

Some photos of where I'm at in cleaning off the old bottom paint.

This next view is up close to the stuff left.