Originally Posted by brak
I know this is a really old thread, but I'd like to follow through (people rarely do and it is always interesting to me how things worked out).
So - the time referenced in my message above (3 years ago) I used zinc prop paint without a primer. It was off the prop completely in less than 2 months.
I did the same thing next year but cleaned the prop and used the primer first, also applied the same treatment to the bronze rudder gudgeons. The result - it adhered in some places (so much that I had to later power sand it off) while completely dissolved in others, in nice round swiss cheese pattern - again in just a few short months.
I.e. - I doubt it protects against much osmosis, if anything it either promotes it or at least simply gets removed very quickly. It also does not help in any perceptible way against barnacles, only making situation worse because now I have to remove both barnacles and that stuff. I ain't doing that anymore.
Speaking only for myself, I have used the Pettit Zinc Coat Barnacle Barrier Coat on my Stainless Autostream prop and bronze shaft for the past four years with great results. The boat is located on Upper Chesapeake Bay - Patapsco River - Brackish Water. I remove any paint build up ever other year using a wire brush attachment on a drill followed by a wipe with thinner. It takes me about 30 minutes to do a through job. I do not use any primer. I apply per directions 2-3 coats with in 5 minutes of each other in 60 degree temp. http://www.pettitpaint.com/fileshare...ds/1179320.pdf
The boat was just pulled today, the zinc paint was last applied March of 2009, the boat is keep in the water year round. I will take pictures tomorrow evening and will hopefully have them posted to this thread by Saturday. I can tell you that I have a 99% Barnacle free prop and shaft, you'll see soon enough. Most everyone in the boat yard uses it as well with similar results?