Removing barnacles from CopperCoat

[geoffschultz]

I have new catamaran which was constructed in South Africa. I had the bottom CopperCoated. One the way from South Africa to the US, we were at Clarkes Court boatyard in Grenada for 3 weeks. The water there is terrible, with lots of nutrient-rich water flowing downstream from a rum distillery. Once we left, I dove on the boat and was amazed at the number of barnacles adhering to the hull. I spent several hours scraping them off with a plastic scraper. The barnacles attached to the waterline ablative popped off cleanly, but the ones attached to the CopperCoat left their foot. I am now hauled out in Maryland, and can address this issue, but how do I get them off?

 

[dLj]

I have new catamaran which was constructed in South Africa. I had the bottom CopperCoated. One the way from South Africa to the US, we were at Clarkes Court boatyard in Grenada for 3 weeks. The water there is terrible, with lots of nutrient-rich water flowing downstream from a rum distillery. Once we left, I dove on the boat and was amazed at the number of barnacles adhering to the hull. I spent several hours scraping them off with a plastic scraper. The barnacles attached to the waterline ablative popped off cleanly, but the ones attached to the CopperCoat left their foot. I am now hauled out in Maryland, and can address this issue, but how do I get them off?

View attachment 239607

The only way I've ever been able to do it is by using a sander. Maybe someone else here has had better luck using some other method.

dj

 

[dmax]

Sharpened paint scraper, round the corners to prevent gouging. You can try muriatic acid to dissolve them, though I never have.

 

[dlochner]

Sharpened paint scraper, round the corners to prevent gouging. You can try muriatic acid to dissolve them, though I never have.

I've used Muriatic acid (hydrochloric acid) to remove them with some success. Mary Kate On/Off will also work. I've only done this with barnacles on gelcoat, not sure about how it will work on the epoxy in copper coat.

 

[BigEasy]

You’re going to have to recoat with at least one coat of ablative, so may as well sand lightly with 80 grit paper to remove remaining barnacles & barnacle bases.

 

[Spindrift NH]

I use a spray bottle with vinegar. spray a few barnacles & let it work for a minute then scrape, sometimes needs a respray. It’s slow going but works and not using chemicals like muriatic acid.

 

[colemj]

When we had coppercoat, I just used a paint scraper or chisel. One at a time, scrape them off. Hydrochloric (muratic) acid should also work, although it will dissolve the existing surface cuprous oxide, and require sanding again to reactivate the coppercoat.

Personally, I would just paint over the coppercoat with a real antifouling. That's what we did. We had a perfect professional coppercoat application. The surface was sanded gelcoat smooth with a perfect even cuprous oxide patina. Crap grew on it like crazy in the tropics, as you found in Grenada. I had to scrape our bottom every two weeks to keep the boat sailing. There are still a lot of boats I meet in the tropics who claim to be happy with their coppercoat. When I ask them how often they need to scrape it, they tell me every two weeks.

Needing scraping every two week is not antifouling in my book.

Meanwhile, we painted over the coppercoat 10 months ago with an inexpensive antifouling paint (Sigma Ecofleet 530, which in the US is called Ameron ABC3), and I have yet needed to clean it. It sat in a fetid Panama marina for several months, then through the South Pacific tropics. I dove it yesterday and found a dozen tiny pinhead-sized barnacles and no soft growth.

The one advantage of coppercoat is IF you have a glass-smooth application, and your picture suggests you do not, then you can scrape it with a metal scraper without worry of losing it, and it will be a faster bottom than antifouling paint. Otherwise, it is only as fast as any antifouling paint, but requires more work to keep it that way.

Mark

 

[dlochner]

I use a spray bottle with vinegar. spray a few barnacles & let it work for a minute then scrape, sometimes needs a respray. It’s slow going but works and not using chemicals like muriatic acid.

Vinegar works because of the acetic acid in the vinegar. It works slowly because it is diluted to about 5%. Higher strength vinegar is available that is about 30% acetic acid usually marketed as agricultural vinegar or cleaning vinegar.

Muriatic acid is hydrochloric acid at 30%. Hydrochloric acid is one of the simplest acids, consisting only of hydrogen and chloride. It is also know as stomach acid, as that is produced in your stomach to help digest food.