Zinc Baranacle Paint on Mast

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Mar 8, 2011
296
Ranger 33 Norfolk
I'm almost embarrassed to ask, but does anyone know why Pettit Zinc Coat Barnacle Barrier isn't recommended for aluminum? Well, the can doesn't specifically say it can't be used on it. . .but I have found some sites listing it as "NOT FOR USE ON ALUMINUM, FIBERGLASS OR WOOD" :redface:

Just on observation of whats on the back of the can, compared to regular cold galvanize spray paint (which says it is fine for aluminum), Pettit has 2% less zinc and costs $15 more :doh: I'd just like to know if I should run out to the boat and scrub this stuff off before my mast dissolves, lol. I have emailed Pettit, but not sure how long it would take for them to respond. . .

If you are curious, I was spot treating the areas under some SS tangs and brackets after I sanded down the white powdery corrosion (looked worse than it was). Since I had the can already, I was thinking it was a convenient barrier that matched the color of my mast. I reassembled everything with lanacote as well. . .

Didn't think much of it till today during lunch (I did it over the weekend). . .then had to google, lol. . .

Um, yes I'm a Compulsive Worrier :dance:
 

MrUnix

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Mar 24, 2010
626
Hunter 23 Gainesville, FL
Just a guess, but I imagine it's because dissimilar metals (zinc + alum) don't play nice together in a marine environment :)

Cheers,
Brad
 
Mar 8, 2011
296
Ranger 33 Norfolk
I checked that before hand. . .both are close on the galvanic series, Zinc being even less noble than Aluminum. . .there really close, figure they would be fine. . .but I'm no chemist :redface:

 
Oct 26, 2005
2,057
- - Satellite Beach, FL.
I think they mean UNDERWATER!
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Salt air too. Contact between dissimilar metals at the top of the mast will cause corrosion in the less nobel metal too. Also, those stupid self tapping steel screws they use to assemble aluminum screen room frames eventually rot and fall out here on the coast.
 
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