Removing Old Ablative Paint ?

Warren Milberg · Jul 15, 2012

I would start by pressure washing with a pressure washer of less than 2,000 psi and on an angle of attack of about 45 deg. Practice on a piece of wood if you are not familiar with pressure washing a boat in order to miminize the possibility of damage. My guess is that you will be able to remove most, but not all, of the old ACT. I think you will then need to sand (and fair) the bottom prior to using the Unepoxy. I don't think you have much to worry about in regard to the epoxied blisters unless they are failing, in which case you want to be able to repair them anyway.

Tom Hoffman · Jul 15, 2012

I got an old boat in 2010 and it had a really ugly old blue bottom paint, I don't know what it was. Any way, I opted to sand it off. We just used 80 grit on a ROS which had a lot of power. My helper wore a breathing respirator and goggles to keep the dust out of places where it didn't belong. We tried to just get the paint and not get into the gel coat. We probably did, they on the advice of a Marine Architect who's counsel I valued, he said that since we had most likely scarified the gel coat, we needed to seal it with a 1 part poly something paint, I had bought Petit EzPoxy and had a gallon on hand. He did some research and low and behold. That happened to be the exact brand and formulation that he said I should use. We put it on and now in it's third year of living in Marinas for weeks if not months, and on and off the trailer numerous times. The bottom still looks as good as ever. The above the water line is what has been taking a beating from me running into docks etc.

Before:

After Sanding:

After Painting:

Sorry, no current pictures, but I am contemplating painting the top sides with exactly the same stuff, It seems to wear very well. We did paint the interior of the boat with it as well.

Tom...

rogerlwhite · Jul 15, 2012

Once you get the ablative paint good and wet you can wash most of it off with a sponge. I did mine shortly after it was removed from the water and it came off really easily.

finding41 · Jul 15, 2012

I power washed mine this spring with 2200psi. Nothing! It was out of the water for 2 years before I got it and the bottom paint was on Hard. Lots of chips in it. It would rub off on your hand but not with the power washer. I'm sure it took off that fine layer that rubbed off but nothing noticeable. I expected it to fly right off in chunks when I power washed. I plan to remove it this fall. I'll check it once I pull out.

onecoolair · Jul 15, 2012

David S said:
My fiber glass O'day 22 has 4 year old Interlux ACT and I am planning on repainting the bottom with Pettit Unepoxy, $109/gl. It has faded to a lighter color and rain water has run lighter color streaks on the under side, the white gel coat and blister repairs are beginning to show through the blue and the paint has rubbed off where the boat has slid on and off the trailer bunks.
I am trying to decide whether to use paint stripper, sand it off or use a paint scraper. I have a pressure washer also if that would do the job, the bottom has hundreds of blister holes repaired with epoxy, should there be a caution using a pressure washer across the blister repairs?
I started to hand sand the bottom and the paint is real soft and comes off rapidly as a cloud of dust as fine as baby powder and even comes off scrapping with my finger nail. It would seem questionable to use a liquid paint stripper?
Like to hear some of your comments and experience's.

David S

By the way, Phil, why don't my post have a blue gray icon that says NEW in front of it in that first column in the ALL DISCUSSIONS FORUM ?

OK sailors jump on that last comment

David do not use a paint stripper.....It will blister the good gel-coat finish that is there down to the glass making for way more problems. I used it once up in the center board well and it was a disaster to fix! Plus it burns like hell!!!

First ...where a respirator and use a good sander with foam pad and a good grit sand paper. To get the bulk of it done. Second you can then use a sanding block and wet sand. Tiring work but the only real choice I can see.

Then I learned how to do it right.....

I had a mac-26 a ways back and I left the boat in the water most of the year. I was lucky I had a trailer so I would pull it from time to time to wash bottom and wax top sides. I found using an ablative water based bottom paint worked best. Made for easy touch ups with a foam brush plus clean up was a cinch. When doing the whole boat would roll and brush tip it on.
Now I own a 36' boat and I do not have it so easy....but I can stand up in the head and it has a great shower!

kenn · Jul 16, 2012

onecoolair said:
David do not use a paint stripper.....It will blister the good gel-coat finish that is there down to the glass making for way more problems. I used it once up in the center board well and it was a disaster to fix! Plus it burns like hell!!!

I stripped our small boat's bottom 3 years ago. Sanding is nasty, if you can't properly contain the work area - requires a ventilator, puts toxic material into the air, damages the gelcoat, and is just too much work.

There are some general purpose strippers out there (usually intended for furniture) that might say on the can that they are OK for fiberglass... but they aren't! Specifically, the product called "Circa 18**" or something like that. Avoid!

There are several chemical strippers intended for boats that do not attack the gel coat. Shop at a proper marine store, or seek advice before purchasing.

After doing alot of testing, I opted to complete the job with a soy-based stripper (Franmar Soy-Strip). Unlike the more conventional strippers, this stuff is non-toxic right out of the can, is much less of a skin irritant, doesn't require the use of a respirator or bunny-suit. It is slower than more aggressive chemicals, but it also stays wet longer. The best part is that it is water-soluble, which means that after scraping, you can follow up with a scrub-brush and soapy water, or a pressure-washer, to really get the rest off. It did take two applications to completely remove the ancient bottom paint, but the gelcoat was spotless and intact.

I'd do this again. Much more civilized than sanding, for a small boat.

onecoolair · Jul 17, 2012

So they make a paint stripper for gelcoat now....sure could have saved me sometime and grief back then.
Thanks for the info.

Manureva · Jul 20, 2012

Tom Hoffman said:
I got an old boat in 2010 and it had a really ugly old blue bottom paint, I don't know what it was. Any way, I opted to sand it off. We just used 80 grit on a ROS which had a lot of power. My helper wore a breathing respirator and goggles to keep the dust out of places where it didn't belong. We tried to just get the paint and not get into the gel coat. We probably did, they on the advice of a Marine Architect who's counsel I valued, he said that since we had most likely scarified the gel coat, we needed to seal it with a 1 part poly something paint, I had bought Petit EzPoxy and had a gallon on hand. He did some research and low and behold. That happened to be the exact brand and formulation that he said I should use. We put it on and now in it's third year of living in Marinas for weeks if not months, and on and off the trailer numerous times. The bottom still looks as good as ever. The above the water line is what has been taking a beating from me running into docks etc.

Before:

After Sanding:

After Painting:

Sorry, no current pictures, but I am contemplating painting the top sides with exactly the same stuff, It seems to wear very well. We did paint the interior of the boat with it as well.

Tom...

That last picture does not look like ablative paint, and i would not want bottom paint inside my boat since it is supposed to wear off and mark anything that touches it. Your boat does look good.

Tom Hoffman · Jul 20, 2012

mesange said:
That last picture does not look like ablative paint, and i would not want bottom paint inside my boat since it is supposed to wear off and mark anything that touches it. Your boat does look good.

The last picture is of the bottom of the boat painted with EzPoxy which is a Polyurethane from Petit. It is rated for Top Sides and so far it has worked well for a bottom paint too. It is super easy to use and is smooth and self leveling with very little tipping when done. We are exclusively fresh water and so the need for the marine growth inhibitor is not really a consideration.

Just pulled the boat and brought her home after about 6 weeks in the Mississippi and there is nasty stuff on it and we didn't get a chance to wash it off right after. So now it is rock hard. I am sure it will come off with hot water and some simple Green soap. Maybe a little pressure washing too.

Joe · Jul 21, 2012

Tom Hoffman said:
Just pulled the boat and brought her home after about 6 weeks in the Mississippi and there is nasty stuff on it and we didn't get a chance to wash it off right after. So now it is rock hard. I am sure it will come off with hot water and some simple Green soap. Maybe a little pressure washing too.

If it's brown.... it's algae... which will harden up pretty quick when exposed to air. Good news it will easily come off with a little diluted, acid based toilet bowl cleaner.

CharlieCobra · Jul 21, 2012

We use Peel Away but are going to Hydroblasting soon. We'll be able to blow the bottom paint off a boat in a few hours and not even hurt the barrier coat. Looking foward to this new process.

Tom Hoffman · Jul 22, 2012

Thanks Joe

Joe said:
If it's brown.... it's algae... which will harden up pretty quick when exposed to air. Good news it will easily come off with a little diluted, acid based toilet bowl cleaner.

Joe, Thanks for the tip. I'm sure it will be helpful. We managed to bump into the guide bunks on the trailer as we were pulling it out and while wet, it just was wiped right off. Now is very hard after being pulled 200 miles.

Will work on it this next week.

Tom...

Ormonddude · Jul 24, 2012

I used a lot of Xylene it wont hurt the glass or gelcoat but has enough burn to it to take off a lot of old paint or at least soften it for scrapping besides that it strips all wax and is a good general prep solution. here is a picture

Merlin Clark · Aug 23, 2012

I just roll barrier coat and bottom paint. I used to not care about that 100th of a knot, but now I understand that an unsmooth surface could be faster (like shark skin)

.
I also us a heavy nap to hold more paint and make sure it's a roller made for use with solvents, as in not for latex only.

rgranger · Aug 24, 2012

I started a longish thread on how to make homemade peel away awhile back.

Here it is...
http://forums.sbo.sailboatowners.com/showthread.php?p=869054&highlight=homemade peel

It worked remarkably well and cost pennies on the dollar.

Merlin Clark · Aug 24, 2012

rgranger said:
I started a longish thread on how to make homemade peel away awhile back.

Here it is...
http://forums.sbo.sailboatowners.com/showthread.php?p=869054&highlight=homemade peel

It worked remarkably well and cost pennies on the dollar.

Very cool! Going to copy and save that!

shnool · Aug 24, 2012

Interlux makes a stripper for fiberglass, called 299E...
Interlux 299E

I haven't tried it yet, and am watching this thread to see what you guys wind up doing. I've already done the sanding project on my previous boat, but this boat I want to be MORE proactive about (last one wasn't as smooth as I would have liked).

Removing Old Ablative Paint ?

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