Copper bronze bottom paint

[Rich VanValkenburg]

I'm a little late again to launch this year for too many reasons, but I just had a good look at Sonja's bottom and something about the bottom paint has changed. There's a local mfgr around here called Kush and I've used their copper bronze for years (before I started the rebuild). It was great stuff, but something must have changed because it peels right off in sheets during the haulout wash, and it turned a wierd gray-white color that was marbled. The stuff that sheeted off showed the older paint that was underneath still a new penny color.

I need some input as to maybe why it did this, and what else I could use now that my favorite paint seems to be junk.

[S B]

I'm a little late again to launch this year for too many reasons, but I just had a good look at Sonja's bottom and something about the bottom paint has changed. There's a local mfgr around here called Kush and I've used their copper bronze for years (before I started the rebuild). It was great stuff, but something must have changed because it peels right off in sheets during the haulout wash, and it turned a wierd gray-white color that was marbled. The stuff that sheeted off showed the older paint that was underneath still a new penny color.

I need some input as to maybe why it did this, and what else I could use now that my favorite paint seems to be junk.
First guess is that the new paint film did not fail,it adhered well to what ever was between it and the first coat. That the old paint showed up a bright metalic colour suggests the new coat stuck to the corosion and peeled it off. What did the old paint look like before recoating. Any pics?

[Rich VanValkenburg]

First guess is that the new paint film did not fail,it adhered well to what ever was between it and the first coat. That the old paint showed up a bright metalic colour suggests the new coat stuck to the corosion and peeled it off. What did the old paint look like before recoating. Any pics?

It was new paint, only in the water about two weeks before we had to haul after finding the tunnel rot of the forekeel. I scrape and save the SlikSeam that squeezes out, and then hand wash the bottom. I can't imagine there was anything there as a barrier.

The only thing I can think of is maybe a change in paint formula.

[Dan McCosh]

Kush stopped making their own bottom paint, and has been selling out some old cans of copper bronze at a discount. Dunno what happened to your paint, but it sounds like a defective batch. I seem to remember someone else makes copper bronze--Petit?--as I used it once some time ago. I stopped mainly because it has no antifouling to speak of, just looks nice before you put the boat in the water. It was originally formulated for Chris Craft type runabouts, rather than sailboats. Might talk to Kush about the problem--they are pretty good. Their topside enamel is great stuff.

[rbgarr]

FWIW there are five quarts of Pettit SR-21 bronze antifouling up on eBay right now. Don't know how old they are though: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=250449410434&viewitem=&sspagename=STRK%3AMEWAX%3AIT

[Rich VanValkenburg]

Dan, that's bad news as far as I'm concerned. If copper bronze is a thing of the past, can you suggest an alternative that might be as hard?

[Dan McCosh]

Personally, I don't see any advantage in a hard bottom paint. It's hard because it is resin-rich, which inhibits the leaching of antifouling. I've usually used the softest paint--which blows off with a pressure washer. Lately, I use a harder paint, the equivalent of Bottomcote. The bronze stuff is mainly decorative, and the only advantage I can see is if you trailer most of the time. This is how most CC runabouts live these days.
The color looked particularly good, which is why I tried it for a year or so. When I used it, it was made either by Interlux or Petit--and I think it is still available. I'm not sure what Kirby's makes. I was at Kush asking about his bottom paint, when he told me they didn't make their own anymore--he is handling some other brand, which i am not familiar with.
Frankly, I am pretty cynical about bottom paints around here. Nothing seems to actually keep algae off, even the newfangled additives. I end up using pretty basic stuff, repaint every spring, and store in the water in the winter. The boat looks like shag rug in the spring when we haul. We also use a lot, due to the wetted surface, so I look for cheap. The guys who race keep cleaning with divers. I used to have a guy next to me who had a compressor at the dock and wet-sanded underwater using a mask every time he went racing. I just go sailing.

===Just checked. Pettit still makes the stuff. Called Pettit Racing Bronze bottom paint.

[Rich VanValkenburg]

I always had good luck with their copper bronze, but that was 18 years ago before all the pain and agony started with the rebuild. It was clean at haulout, no growth of any kind.

I think I solved part of the problem today. Stopped at Kush, showed him a big flake that peeled off and the strange white streaks through the surface. On the other side, the side mated to the last good bottom coat it was shiny and like a penny. He said it was the same formula as it's been, a polyurethane. That was it. Back 18 years ago I think it was a linseed oil based resin, was a lot thicker, and dried within minutes. I used to use almost three quarts for the whole bottom but today it took less than a quart. Goes on like water. During a rebuild like we had, I was pretty much out of the mainstream. Things changed and I wasn't aware of it. And you're right, it isn't even considered an anti-fouling paint like I think it used to be.

[Dan McCosh]

Kush's old paint was a pretty basic copper alkyd--similar to lots of other paints that used to be regular old bottom paint--Red Hand, etc. That is pretty much what I look for today. I did notice the copper-bronze stuff in the store, which seemed like Pettit. Maybe the name of their old basic paint was copper-bronze, as opposed to the shiny Chris Craft stuff. Oddly, last I looked, they still listed their own bottom paint on the web site, but they don't make it any more. Are you looking for that shiny copper/bronze look? The stuff I use is more like a dark red color.

[Dan McCosh]

I just looked at heir web site, and the copper-bronze doesn't look like any of their other paints. It also says that it is a polyurethane, which I don't think is too good under water. The rest of the bottom paints they sell (not their own) are strong antifouling, but I have no experience with them.
I did paint the hull with their enamel this spring (and the deck last year), and it's the best enamel I have ever used. Don't mention to them how low their price is, however--it might give them ideas.
I also like their varnish, but haven't had too much experience with it for durability. It also takes a long time to dry.

[Rich VanValkenburg]

It also says that it is a polyurethane, which I don't think is too good under water.

I think you're right. Looks like I'm in for a stripping after this season since I think the stuff is just going to keep flaking off. He did mention that they still make the copper/bronze themselves. It's the color that I'm after, the soft paints just don't get it for me.

We went on a wild antique boat show chase this morning. The web site said the Algonac show was 26th, 27th, and 28th, along with the antique outboard meet. Wrong! it was just Saturday and was over at 4pm. I even washed my WoodenBoat shirt for the occasion.

Was a nice day for a ride anyway and we stopped at St. Clair for the art show, then sat almost under the bridges at Port Huron and watched the water go by...quickly. Nice to see the CLEAR Caribbean Blue Lake Huron water, in contrast to Milo's Huron River thread.

[Dan McCosh]

Might try the Pettit--I never had any trouble with it flaking off, etc. We generally sand the bottom before painting, however. It's supposed to have an "epoxy" base--whatever that is supposed to be--similar to their regular bottom paints.

The Algonac show is good--We stumbled on it once while just driving by. It's mainly large cruisers, along with the runabouts. Not much left of the old Chris Craft plant these days, however.

Just talked to a friend who was cruising in the North Channel in June. Said it had snowed two weeks before he got there. Lake Huron just got above 50 degrees. Things are warming up.

[Peter Malcolm Jardine]

Both Pettit and Interlux still make a copper bronze bottom paint. I buy the interlux only because I can't get the pettit, and in Canada, they only market the stuff in quarts:mad: