What kind of Bottom Paint have I got?

[arf145]

Yeah, yeah, it's my boat, I should know, right? But how can you tell, when you didn't paint it?--it was last painted under the PO's regime. I just want to know if it is ablative or not, so I'll know what to go with without stripping the bottom.

Here are the clues: it has some buildup-I can definitely see two or three distinct coats up near the waterline. The current texture is slightly rough, if that helps. The color comes off on your finger a bit when you rub it, but not as much as some others in the boatyard.

The surveyor suggested that it might ablative, but I'm not so sure. I did ask the PO's boatyard. They had no record of painting it, but only had 2006 and later records on hand. But they did say that they normally use Interlux non-ablative, and only change from that if someone makes a special request, which was unlikely with this PO--the boat barely went out for 5 years.

Can anyone suggest what I should be looking for to figure the paint type?

Thanks.

Tom

[bubb2]

Take a power washer to it. if it washes off it is ablative. If it come off in chips it is hard paint

[Faster]

Didn't find any old cans in a locker somewhere? Can you contact the PO to ask?

Buub's trick may work.. but if you can easily see multiple layers now perhaps its time to get rid of it and start over anyhow, with the paint of your choice.

[arf145]

No cans or other evidence like that. And the PO was uninvolved--had no idea about the maintenance--bought the boat for his son, who didn't use it.

So just how soft is ablative to the touch--or say the edge of a putty knife? Should I be able to sort of gouge out a chunk vs. chip out a piece?

If I wanted it all off, but didn't want to sand, are there paint removers that would work on it no matter what kind it is?

Tom

[sailingdog]

If you don't know the history of the bottom paint on the boat, applying anything over it is a fairly risky proposition... My recommendation would be to bite the bullet and strip the hull down to gelcoat and start from there. The boat will sail faster, be lighter (yes, copper-based hull paint adds a fair amount of weight), and you will have the chance to barrier coat the hull if you want to before you paint.

The easiest way to strip it down to the gelcoat is to sodablast the bottom. Does a really nice job and basically leaves the gelcoat ready to to paint or barrier coat for the most part.

[Fstbttms]

Originally Posted by arf145

So just how soft is ablative to the touch--or say the edge of a putty knife? Should I be able to sort of gouge out a chunk vs. chip out a piece?

Most anti fouling paint will rub off to the touch to some degree. However, an ablative will probably not come off in flakes, chunks or chips. A modifed epoxy might.

[Fstbttms]

Originally Posted by sailingdog

If you don't know the history of the bottom paint on the boat, applying anything over it is a fairly risky proposition.

Since the PO didn't specify to the yard what he wanted on the bottom, it is unlikely that the yard applied anything other than a run-of-the-mill modified epoxy or ablative paint (and most probably the former, IMHO.) If that is the case, he should be able to apply either type safely over whatever is on the bottom currently.

[JimsCAL]

You can put an ablative on top of modified epoxy, but not the other way around. If you don't want to strip the bottom, I would guess you would be safe with putting on an ablative. Try it in a small area and see what happens.

[Fstbttms]

Originally Posted by JimsCAL

You can put an ablative on top of modified epoxy, but not the other way around.

Not true.

Bottom Paint Compatibility Chart Old Paint to Remove Modified Expoxies Copolymers & Ablatives Vinyl Paints Sloughing Paint Thin Film Paint Vivid & Tri-Lux 33 Modified Expoxies Sand & Paint Sand & Paint Sand Well Sand Well Remove Sand & Paint Copolymers/Ablatives Sand & Paint Light Sand & Paint Sand Well Remove Remove Sand & Paint Vinyl Paints Remove Remove Sand Well & Paint Remove Remove Remove Sloughing Paint Sand & Paint Sand & Paint Sand Well & Paint Sand & Paint Remove Sand Well & Paint Thin Film Paint Remove Remove Sand & Paint Remove Clean & Paint Remove

[arf145]

If I read Fstbttms' chart correctly I should just be able to sand and apply a modified epoxy to what is likely there, be it ablative or modified epoxy, and it seems unlikely the yard put anything more exotic than that on it. I'd like to have what we put on last 2 years of weekend use on the Chesapeake.

When the boat was hauled for inspection, it had slime on it but no barnacles, so I guess something was still doing the job--I forgot to mention that earlier.

I'd sort of like to suck it up and get it soda blasted, sailingdog, but we've been sucking it up on a lot of projects (8-0) and I hate to have one more I can put off for a couple of years.

Tom