Originally Posted by xsboats
I use a de-waxing no sand primer, followed by 545 primer, followed by Awl-Grip with griptex added to it for non-skid. The residual wax in the valleys was your problem with adhesion. Awl-grip with aggregate has always lasted longer than the one part non-skid deck paints for me.
I agree with your take on this. They probably didn't sufficiently dewax the valleys. You will first have to remove as much paint as you possibly can, with a wire brush & duct tape!
After thorough solvent washing
, I use a combination of a brass or SS wire brush, followed by a paste of AJAX & water
with a stiff bristle brush. Really scrub the hell out of it! Then a complete power washdown, and final solvent wash. Afterward, 545 Primer & Awlgrip. (multiple rolled coats, with coarse Griptex). Don't over roll, or you'll lift
it. Fix those bad spots with the next coat. You can also ROLL the "spray" formula, and thereby apply three coats in one day, but apply them QUICKLY without working it.
I did experiments, (the cross hatch
test), and found that the "coat early the next day, after primer" chemical bond, between 545 primer and topcoat, is actually BETTER than the "wait several days and sand" bond. It saves a lot of work to get the topcoat on the next morning, and avoid sanding
. ESPECIALLY in those valleys, where you CAN'T sand. This is essential here.
"Grey" primer under the white topcoat, rather than white primer, is opaque, so protects the hull
& deck better from UV damage, and makes it a tad cooler down below as well. I did temp measurements on a side by side sample, half with grey, and half with white primer, and both topcoated with white topcoat. It is a small advantage, but doesn't cost a penny more or take more time.
There are few messes as bad as poor adhesion of anything to anything else on a boat. No matter HOW much work it is, the prep HAS to be perfect.
I spent 6 weeks in a Trinidad boatyard, right at the corner of "spray painter's central". These several spray painting contractors were popping out beautiful work regularly, but their prep was totally inadequate. They didn't use "guide coat" in the sanding
process, so didn't know what was sanded and what was just flat from age. They would run a sander down the side of a hull
in 2 hours, that I would've taken 2 days on. (I used to inspect their work closely, when they'd gone home). There is a reason that third world paint jobs are cheaper. They usually last several years anyway, and the client is usually 2,000 miles away when the paint starts to fail. You can't tell a thing about adhesion on your new paint job, without doing the duct tape "cross hatch" test all over it. NO one does this, and they know it.
This isn't to say that they ALL are too sloppy in the prep, just that MANY are. It's true Stateside too, but to a lesser degree.
If I ever hired someone else to paint my boat, I would be there the ENTIRE time, during the prep work. Worst case... what cost $20,000 to apply, could cost even more to remove, before starting over again. I've been there, it's a BEAST!
Best of luck getting this right,