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Guest · Posted: Tue Jan 11, 2005 3:34 am Post subject: Zinc Chromate

I need to coat the inside of an aluminum pontoon with zinc chromate, in
order to do this it must be thinned. What solvent can be used to thin
zinc chromate?

Len · Guest

Richard@Kollmann-marine.com wrote:

Bruce on horizon · Guest

What you have to worry about is using too slow of a solvent. If the coating
dries before the solvent escapes, you will get blistering. MEK is the
fastest solvent available to the handyman so call the Zinc chromate
manufacturer and see if MEK will react with the coating, if not, spray
away. We use a epoxy primer
http://www.shieldfinishes.com/nauticoat_epn1y1.asp and our reducer
http://www.shieldfinishes.com/nauticoat_srn12.asp reduced no more than 10%
to coat mast systems. How are you going to apply the primer?
Good Luck
Bruce

Shield Finishes and Nauticoat Marine Finish Systems
www.shieldfinishes.com

"Len" <lendenbesten@nospam.hotmail.com> wrote in message
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e.grant · Guest

DO NOT DO IT. Afriend of mine did it a few years in his aluminum sailboat
and had to replace all the aluminum after the galvanic action destroyed
it.(within three years) YOU may be very sorry. The aluminum becomes the
destructive anode rather than the other way around. I know this seems
conterintuitive, because it is used in aircraft, but aircraft are not
constantly immersed. Even though you state that it's the inside of the
pontoon, it could and probably will cause problems. Whats wrong with the
bare aluminum? Efflouresence? Deeply etched? Ever try lightly wiping bare
aluminum with a little ATF (red automatic transmission fluid) to seal the
surface? It works OK and it's cheap. Consult the paint manufacturer if you
want to go with the zinc chromate, there could be a special surface prep
step as well as thinning instructions. Remember, aluminum oxide on the
surface is the protectant for the substrate and unless it comes in contact
with stuff like battery acids, it does corrode but at a very slow rate.
Proceed with caution and good luck.
<Richard@Kollmann-marine.com> wrote in message
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Bruce McCampbell · Guest

This is a classic problem of dissimilar metals. The chromate is the
sacrificial metal in the primer. As it deteriorates first, the aluminum is
saved. The best product to use is a fluid resistant strontium chromate
epoxy primer. It is resistant to the water and when it intrudes, the
chromate is the first to go.Here is a link to the product information.

http://www.shieldfinishes.com/nauticoat_epn1y1.asp

Thanks
Bruce
"Paul Oman" <pauloman@pauloman.com> wrote in message
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e.grant · Guest

per posting of message reply to you and newsgroup,yesterday, I was mistaken,
apologies. My buddy's aluminum sailboat was painted with a copper based
paint that was mistaken for zinc chromate. You can understand why it
corroded away to nothing within three years. Sorry for the
misunderstanding. Lesson: don't use "surplus" paint marked as one thing
when it is something else. If you you do, have it analyzed, first.
<Richard@Kollmann-marine.com> wrote in message
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MMC · Guest

Paul,
Looks like our next boat will be a pontoon (got to go along with the wifes
wishes once in a while) and as I don't have room for a lift, the boat will
be kept in the water.
I've seen damage from bottom paint on aluminum pontoons and thought I could
barrier coat the whole pontoons and then bottom paint. Will this work and
what prep should I do prior to barrier coat?
Only things I know about aluminum is it holds beer well.
Thanks, MMC.

"Paul Oman" <pauloman@pauloman.com> wrote in message
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Paul Oman · Guest

MMC wrote:

MMC · Guest

Thanks Paul.
"Paul Oman" <pauloman@pauloman.com> wrote in message
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