Association Forum - Bottom paint falling off

Assn Members Area · Join

Home.

Association Forum

Ships Store

Cruising

Racing

Technical Tips

Photo Gallery - New

Boat Search - Updated

Manuals & Brochures

Swap Meet

Links

Officer Flag Line & Staff

Bylaws & Constitution

Members Area

Join the Association

Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.

Association Forum

Username:	Password:
Save Password
Forgot your Password?

All Forums

Catalina/Capri 25/250 Sailor's Forums

General Sailing Forum

Bottom paint falling off

New Topic

Topic Locked

Printer Friendly

Author

Topic

Voyager
Master Marine Consultant

Member Avatar

USA
5379 Posts

Initially Posted - 03/27/2011 : 18:43:07

I am making preparations for launch of Passage in late April (weekend of 23rd) and needed to clean the decks, topsides and cabintop, and replenish my bottom paint. Last season, when they pulled her out, the bottom came out of the water looking pretty clean. She came out in early November, directly after which we had a hard freeze.

Two years ago, I had taken the bottom paint completely off, applied six coats of Interlux barrier coat and applied a coat of bottom paint. This photo was from that time.

Passage Bottom Paint

-------------------------
Passage in Spring of 2009

Since then, I've painted one additional coat of bottom paint (total 2 coats).

Today, when I started prepping the bottom, I decided to knock off any flakes and chips beforehand. That's when I noticed a few larger flakes. Then I took my paint scraper and passed it over the bottom. As I scraped, the paint came cleanly off down to the barrier coat.

In about 15 minutes, I had taken all the paint off the first 4 feet of the bottom from the bow aft. I had a big tarp on the ground to catch the flakes. I reckon that in another 4 hour session, I can probably scrape off the rest of the paint.

I am baffled why on earth the paint is now flaking off so easily. I wonder whether last fall when the bottom paint was still wet, and we had a hard freeze, that caused the paint to expand or contract differentially than the barrier coat? This has been a really cold winter with a lot of snow, thawing and freezing - has anybody else experienced anything like this?

Another theory is that when I originally painted the barrier coat, that I hadn't begun painting the bottom paint over the barrier coat soon enough, before the barrier coat finished drying. Some paints must be painted on while the undercoat is still tacky.

Puzzling

Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain � Milford, CT

Edited by - on

OJ
Master Marine Consultant

Members Avatar

USA
4382 Posts

Response Posted - 03/27/2011 : 19:17:32

You mention the brand of the barrier coat but not the anti-fouling paint . . . . .

Possible compatibility issue?

Edited by - OJ on 03/27/2011 19:18:26

Stinkpotter
Master Marine Consultant

Members Avatar

Djibouti
9081 Posts

Response Posted - 03/27/2011 : 19:53:56

You might be on to something with the freeze... Bottom paint, particularly the ablative type, is not impervious to osmosis of water--that's why you use a barrier coat. So, if water molecules penetrate the paint and then turn to tiny ice crystals... POP! A little more time and they might have evaporated out.

However, I'm also curious about the paint you selected. And I might suggest, if you do finish the removal, that you apply a no-sand primer on the barrier coat, and then the paint on top of the primer within the prescribed time window--don't let it totally set up more than recommended.

...or, call Interlux (especially if you used 2000 and an Interlux paint) and ask them. In fact, cancel my previous suggestion and go with this.

Edited by - Stinkpotter on 03/27/2011 19:54:37

Voyager
Master Marine Consultant

Members Avatar

USA
5379 Posts

Response Posted - 03/27/2011 : 20:29:06

I used West Marine CPP bottom paint -- the usual ablative stuff. I am hoping that the rest of the paint comes off as easily as the first 4 ft. I kinda like the idea that I can strip the paint in an afternoon with a simple paint scraper. It prevents that whole "surface of the moon" problem you get after 5-7 years

Edited by - on

Dave5041
Former Mainsheet Editor

Members Avatar

USA
3758 Posts

Response Posted - 03/27/2011 : 21:37:16

CPP is a soft ablative and doesn't withstand scrubbing, let alone scraping. Call WM or Petit, but it shouldn't have a bonding problem. I could believe the moisture absorption and freezing issue with a soft ablative. A new barrier coat should be fully cured and solvent cleaned before applying bottom paint.

Edited by - on

Voyager
Master Marine Consultant

Members Avatar

USA
5379 Posts

Response Posted - 03/28/2011 : 18:19:43

I did the recommended process with the barrier coat -- washed it with solvent before applying the CPP bottom paint. I assume it was the freezing last fall that did it.

In retrospect, I don't mind that the paint is coming off so easily -- the barrier coat is still intact, so I won't get a bottom paint-buildup as quickly over the coming years.

Like I said, the bottom paint held up great in the summer of 2009 -- little marine growth, and in the summer of 2010 -- none to speak of. So, I'll scrape with a simple paint scraper, wear a respirator, goggles, hood and gloves, I'll collect the chips in the tarp, then roller on a new coat of bottom paint, and be ready for April 23 for my splash! God willing!

Edited by - on

bigelowp
Master Marine Consultant

Members Avatar

USA
1779 Posts

Response Posted - 03/28/2011 : 19:22:55

I have had a similar experience. While never having striped and applied barrier coat, when I received Limerick she had been on the hard for several years. In the dead of winter (read GD cold days) I scraped the bottom very easily. In elapsed time of 8-9 hours I had 95% of the paint off of the fiberglass and 20% off the keel. I primed the keel and applied one coat black CPP and two blue. The bottom looked very good and after the first season still looked good requiring only a little clean up. I applied a new coat for the second season and when she came out all looked good. However in spring while cleaning I experienced large sheets peeling off. I assumed that not barrier coating was the route cause problem. At the end of the season she came out and looked ok. Last year (season three)I tried spot-touch up but when rolling the new paint on it pulled the old paint up and off. I was able to cover all questionable areas with paint and again, when she was hauled at the end of the season all looked ok. While I have not had a chance to start spring work yet my thought was that between any possible formula change to the paint, the number of existing coats, and my lack of surface prep the combined result was one heckofa mess. I had hoped to soda blast the bottom and barrier coat this year, but based on my work schedule that will not happen and I instead expect to slap on more of the same. the good news is that the paint stayed intact while in the water where it is most needed. So while it fails the "20 ft" rule on the hard it does keep growth in check while at mooring.

Edited by - bigelowp on 03/28/2011 19:27:31

Stinkpotter
Master Marine Consultant

Members Avatar

Djibouti
9081 Posts

Response Posted - 03/28/2011 : 19:25:10

WM's PCA Gold is a good buy IMHO, with a rebate right now (I think)... It's re-branded Pettit Ultima SR-40, which is well-rated by Practical Sailor (and which I'm buying at Defender's warehouse sale this week). One coat every two years (or more) should be plenty--you can touch up spots, but adding whole coats annually is really unnecessary. If I was starting fresh (after your scrape-down), I might put two coats on--the second being the color I want and the first being a contrasting "signal" coat, and then watch year-to-year for signs of the signal coat. Sailboats don't wear ablative paint off very quickly, and the good ones are effective for several seasons, even when on the hard off-season. My biggest problem has always been the travel-lift and the pressure washing, both of which invariably remove some spots. So I paint the spots (and brighten up along the waterline).

Edited by - Stinkpotter on 03/28/2011 20:31:42

Dave5041
Former Mainsheet Editor

Members Avatar

USA
3758 Posts

Response Posted - 03/28/2011 : 21:00:23

I only touch up annually, normally the leading edges, with CPP. Letting it wear away as designed is the lazy and reasonable approach to bottom maintenance and annual coats are not required in most environments. If you don't have significance growth at the end of the season, just touch up over your signal coat.

Edited by - on

dlucier
Master Marine Consultant

Members Avatar

Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 03/29/2011 : 07:49:10

In the flaked off areas, before overcoating, you may want to sand the barrier coat a little to give it some tooth. Does CPP require sanding prior to using?

Edited by - on

Voyager
Master Marine Consultant

Members Avatar

USA
5379 Posts

Response Posted - 03/30/2011 : 19:04:46

Somehow I was under the impression that one has to replace / repaint the bottom coat every year if using ablative, since when the paint dries the copper biocide somehow becomes ineffective. I guess I believed the propaganda. So I have always sanded the bottom and repainted every year, whether she needed it or not. Have I been misled?

Don,
I usually sand the previous year's remaining paint with 80 grit sandpaper (wearing a respirator, goggles, gloves and paper headgear) and then repaint new bottom paint using a paint roller.

Before I scraped the hull down to bare gel coat in 2009, I just painted over the old paint that was on the hull - aka, the surface of the moon. After the big scrape, I added barrier coat, and so last year I roughed up the bottom paint just enough with 80 grit sandpaper, and just painted over. It remained stuck in place all season in 2010.

Now, the paint has come flaking off. If I remove all the paint, and try to sand the remaining barrier coat, I will reduce its water-repelling properties. The idea is that each coat of barrier coat acts like "shingles" on a roof. You need 6 coats of barrier coat to provide enough "shingles" to keep the water out of the gel coat and vinylester of the hull, preventing blisters.

If I were to rough up the barrier coat, I'd compromise its water repelling properties. I might look into finding some kind of primer to go over the barrier coat, then rough that up with sandpaper.

But as I said above, I like the fact that the old paint slides off so easily every spring.... .... so, perhaps I'll leave well enough alone. This spring I'll scrape it, then paint it, and leave it at that.

Edited by - on

dlucier
Master Marine Consultant

Members Avatar

Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 03/30/2011 : 20:07:49

I believe Interlux recommends sanding the Interprotect barrier coat when overcoating with some antifouling paints.

Edited by - on

TakeFive
Master Marine Consultant

Members Avatar

2272 Posts

Response Posted - 03/30/2011 : 20:19:33

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Voyager
 Somehow I was under the impression that one has to replace / repaint the bottom coat every year if using ablative, since when the paint dries the copper biocide somehow becomes ineffective. I guess I believed the propaganda. So I have always sanded the bottom and repainted every year, whether she needed it or not. Have I been misled?<hr height="1" noshade id="quote"></blockquote id="quote">
According to Don Casey and the other paint references, hard (non-ablative) paints are the ones that lose their effectiveness when hauled out for the off-season. The copper degrades faster when exposed to air. So they need to be left in the water year-round, or if hauled for the winter they need to be repainted shortly before launch. For this reason, they build up an awful lot if stored on the hard every year.

Ablative paints do not need to be replaced every year. Their outer surface may lose effectiveness when hauled, but that ablates off quickly. You can help the process with a gentle scrubbing before launch, since that will ablate the dead layer. With ablative you just need to touch up the worn areas each year, which is why so many people put a different colored indicator layer underneath.

I am planning to use Pettit Vivid this year, which is a "hybrid" hard ablative paint. Last year I had a problem with ablative scraping off the waterline due to fast river currents and driftwood scraping repeatedly along the waterline. Hopefully Vivid will give the best of both worlds. Plus, I hope the bright blue color will look really cool.

This is my first time painting the bottom (other paint was there from PO), so I hope I don't get the kind of flaking you're having.

Edited by - TakeFive on 03/30/2011 20:24:14

Stinkpotter
Master Marine Consultant

Members Avatar

Djibouti
9081 Posts

Response Posted - 03/30/2011 : 21:15:47

Rick--unless you're removing all of the PO's paint, make sure Vivid is compatible with it, or "flaking" could be an understatement.

Bruce--Rick is right. Ablatives generally remain effective through extended haul-outs, while hard paints typically deteriorate in air in a matter of a couple of weeks, and have short "time to launch" recommendations. See page 266 in the new WM catalog.

I like PCA Gold (actually Pettit Ultima SR-40) partly because it has an anti-slime agent, which I don't believe CPP has. My slip is in brackish, high-slime water, and people here who use paint that doesn't resist vegetation get grass as well as algae.

Edited by - on

TakeFive
Master Marine Consultant

Members Avatar

2272 Posts

Response Posted - 03/31/2011 : 07:05:34

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Stinkpotter
 Rick--unless you're removing all of the PO's paint, make sure Vivid is compatible with it, or "flaking" could be an understatement.<hr height="1" noshade id="quote"></blockquote id="quote">
In my haste, my message was not as clear as it should have been. The ablative that wore off quickly was only on the rudder. I will remove that completely, since hard paint over soft paint is a bad idea.

The rest of the boat is WM BottomShield. Very stale, I guess at least 3 years old. Pettit's compatibility chart says that Vivid is compatible over top it as long as I sand first. I called them and confirmed what I am planning to do. There are never any guarantees that it will stick, but I'm doing as much surface prep as I can. I'm doing lots of sanding to get rid of some of the accumulated orange peel. I don't want to strip it all off because it's adhering pretty well, and what I've seen so far on this boat is that intercoat paint adhesion is good - when a section of paint flakes off all the coats flake off all the way to the fiberglass. So if I've got paint that's sticking pretty well, I want to leave it on the hull and paint over it.

For the small sections of paint that have flaked off, I am still trying to figure out what to do. Dewaxing is obvious. But not sure whether to sand or do sandless primer. I would like to build up the coating thickness a little in the bare spots to make the whole thing smooth. For now I am feathering the edges of the chips to keep them from being rough.

I was going to go with PCA Gold before I decided to try Vivid. It looks like WM just put the PCA Gold on sale again today, so I have a few more days to second-guess my paint choice before the Vivid comes in to the store. The Pettit guys said that Vivid is a little harder, which I think would last longer with the currents and driftwood on my river. I am also concerned that if I try a full ablative like PCA Gold and don't like it because it wears too fast along the waterline, then I have to remove all of it if I want to go back to hard paint. OTOH, if I try Vivid and don't like it, it will be easier to paint over next year with an ablative. Painting soft over hard is always better than painting hard over soft.

I know I'm over-analyzing this. I used to work in a paint lab before moving on to R&D on ink jet inks.

Edited by - on

bigelowp
Master Marine Consultant

Members Avatar

USA
1779 Posts

Response Posted - 03/31/2011 : 13:30:43

With ablative paint one of the many factors is how quickly it wears off your boat in the area that you sail/dock/moored. Many suggest, and I have successfully done, the first coat in one color and then subsequent coats in a different color so you can see when coat(s) have worn away. In my case the first year wear told me that I really should paint every year (note: I moor my boat from May through October). Since then I do not believe I have had build-up of paint as wave action seems to remove close to what I apply in spring. Anyway while ablative paint can handle multiple seasons and still remain effective in preventing growth, it may wear off over a long season or if in difficult growth accumulating areas. When it wears off the resulting clean up, removing barnacles, growth, etc, is a rough job so I would err on more rather than less paint. All that said, using PCA Gold has seemed to not wear off quite as much as the CPP, which I am presuming is because the slime additive is doing its job more efficiently. I admit, that I am pulling pepper from dirt here, but still for those who store their boats on trailers between use I would think that you can easily get more than one, if not several, years use from each coat of whatever type of ablative bottom paint you might apply

Edited by - on

Voyager
Master Marine Consultant

Members Avatar

USA
5379 Posts

Response Posted - 03/31/2011 : 18:52:22

This year, then, I will take off all the flaking paint, give it a good solid roller paint job and leave it at that. Next year, if the paint sticks, I will touch it up. That will save me time and money. This is a great forum!

Edited by - on

Voyager
Master Marine Consultant

Members Avatar

USA
5379 Posts

Response Posted - 04/09/2011 : 21:36:53

I spent part of last weekend and all of today scraping the bottom paint. I got all the flaking paint off the bottom and most of the rest. So tomorrow, I plan to clean the hull above waterline, touch up the polyglow and next week, repaint the bottom.

Edited by - on

Topic

New Topic

Topic Locked

Printer Friendly

Jump To:

Association Forum

Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.