Tim Shoppa wrote:

I've got an aluminum panel (front of a very fancy instrument) that I
want to re-paint. Current paint is pretty shabby, but then again it's
from 40 years ago. I'm sure I can get the old paint off (between
strippers and sanding) but what's the next step?

What's a good pre-painting etch for aluminum? I've used
phosphate-based etches before but something tells me that this isn't
the best thing for aluminum.

And after the etch, I'm probably limited to cans of spray paint.
Although going to an automotive paint shop and asking them to load a
paint can for me is a possibility, I don't walk in without a clue as to
what I want to buy. OTOH if I can buy it off the shelf then that's
great too.

I can bake the panel after painting, in my past experience (with
discount-store brands of spray paint) this makes a big difference in
durability.

So any advice before I walk in the paint store and make a fool of
myself?

Tim.



A good acid etch after a thorugh cleaning and sanding will give good
adhesion for the paint. Oil is your enemy so make sure you have clean
paper towels rather than rags to apply the solvent cleaner. Also make
sure the bottle of solvent, acetone, mek or such has not been
contaminated by someone holding a rag over the opening and turning the
bottle upside down to wet the rag, Many paint jobs have come out second
best doing this little trick by someone with an oilly rag.

I dont know if you can still get it but zinc chromate is the one i
always used. The trick is to put on a real light mist coat and let it
dry for at least three or four days before you put your paint on. For
magniesium we would let it dry for a week before we painted it.




John