Damaged Bottom Paint

[four winns 214]

The bottom on my Sea Ray cuddy is painted with a typical ablative paint. I don't know the exact brand and type. I had the boat detailed by a local shop a few weeks back and one of the steps was an acid wash. The shop claims the acid wash took off some of the bottom paint in one area and left a green mess because the bottom paint was applied "over algae" that was not cleaned off before painting. I showed this picture to a boating friend and he said the green area was caused by the acid wash reacting with the copper in the bottom paint. I would consult the bottom painter, but he winters in Florida and is not around. Before I took the boat to the detailed, the bottom around the keel looked just like the paint above the water line. What do you think?

 

[Maclin]

I am not a chemical guy at all, but just as an observer it seems that any reaction to copper in the ablative would have occurred in more than just that one area...?

 

[four winns 214]

Well, I think once the detailer saw what was happening, he knocked it off with the acid wash.

 

[Maclin]

Ah, the Copper thing sounds more likely then to me.

 

[tpenfield]

Since it is below the waterline, I'm going with a fine film of slime that was on the paint. Time for a power wash.

 

[Chris1956]

Wash it with some baking soda to neutralize any remaining acid and repaint it with another coat of ablative AF paint of the same color. Ablative paint does not last forever, and a recoat is a good thing.

I think the dealer is making up a story to satisfy you.

 

[firstcatch]

My 2 cents. You may want to paint with a primer before another round of Bottom Paint. I have used Seahawk primer with much success.

 

[Chris1956]

Primer over ablative bottom paint is the wrong approach, IMHO. The ablative paint is made to wear away. The primer may stop the wear-away, or may cause the ablative paint to fall off in chunks, which is also bad.

 

[tpenfield]

^^^ +1 once ablative paint, then you go with more ablative paint, unless you remove all of the paint and get back to the bare gelcoat or barrier coat.

 

[fhhuber]

It is possible that there was algae something under the last coat of ablative and the acid got to it... If that is the case then any fix will involve getting the paint off that and then cleaning the algae or whatever it was off before the repainting.

Can't tell by the picture exactly what is going on there. We can just tell that something is wrong.

 

[four winns 214]

When I last had it bottom painted, there was no accumulation of algae so I'm at a loss of how it would just now appear. It's only on the front right side. None on the left.

 

[firstcatch]

Primer over ablative bottom paint is the wrong approach, IMHO. The ablative paint is made to wear away. The primer may stop the wear-away, or may cause the ablative paint to fall off in chunks, which is also bad.

Disagree. The primer is MADE to go over any type of existing paint. It will provide a solid foundation to apply the new paint. But to each their own. Tight lines.

 

[Chris1956]

Sure the primer may stick to the AF paint, however, the AF paint is very soft and made to wear away as the boat moves thru the water. So what happens to the primer when the paint around it wears away? Does it get undermined and fall off in chunks? Does it leave a mound?

​Remember the primer is only as hard as the surface under it. In this case the surface under the primer is real soft. You can rub off Ablative (and most "hard" AF paint) with your hand.

 

[fhhuber]

Could be wax under the paint... that can do weird stuff.

Could be a spot of poorly mixed or applied paint.

Could be it got a shot of concentrated acid instead of the dilute solution used for the cleaning process.

Lots of could bes...

To fix it right... it has to come off.

To find out for sure what happened would require sending it for analysis. Maybe the paint maker would care enough about it to do the analysis to determine the cause. Maybe it would cost a lot of money.

 

[four winns 214]

Update: The person who did the bottom paint on this boat said it was the acid wash, no question. This guy has been doing bottom work for 30 years. Everything from little cuddies like mine to 50'+ cruisers and houseboats.

 

[tpenfield]

Could be the acid wash . . . Is this a big deal ? or a minor issue. Is this going to be prepped and painted again for this coming boating season anyway?

 

[four winns 214]

It IS the acid wash. I went by the shop that has taken care of the bottom on this boat since I bought it in 2006. Showed them the picture above. The shop owner went and fetched a paint tray with the exact product used on my boat, even the same color, and poured a little acid wash on the dried paint in it. I watched it turn the same color green right before my eyes.

The problem I have is that the detailer, who purports to be a "certified" bottom painter, told me the shop who did my bottom didn't prep it right and all he (the detailer) did was to expose the algae. That contention begs the question: Did you lie to me in an attempt to gain a bottom paint job or were you simply unaware of the effect of your acid wash solution on bottom paint? If it was the latter, a lot of good is your "certification".