Posted by Dave Speed on Monday, August 19, 2002 at 11:16PM :
In Reply to: could use some help on paint prep .not pw related posted by Junkyard dog on Monday, August 19, 2002 at 8:47PM :
Why isn't this PW related. Many of these beasties need a good coat of paint after 50 yrs. The trick is to make *your* coat last the next 50 years...
First, I hate to paint over old paint; its usually more trouble than its worth. Remove the old paint via paint remover, sanding or sandblasting as needed. Needless to say, remove all rust (and I mean ALL RUST!!!).
If you don't get it *all*, you're just kidding yourself.
Then make sure the surface is well sanded - i.e. has some "tooth"; I use 120 grit paper on a random orbital air sander. Clean this off with lacquer thinner as oil from the air sander can be a problem.
Then you can use one of the phosphoric acid etch products per the directions. I never had much lick with them, but then I sand and paint the same day in a humid climate.
I like PPG's DP-40 2 part epoxy primer; it does not come off for me or anybody else I've seen follow the instructions. You can thin DP-40 in a certain fashion to act as a "sealer" coat, but this is not usually needed on bare metal.
DP 40 is not, however, a high-build primer to help cover blemishes; minor inperfections in the metal surface are often visible with thin coats. High-build (and subsequent finishing/ sealing) is an advanced topic I'm not qualified to ruminate on.
Follow the instructions on the base coat / clear coat system even if they are a pain.
Take some time and chat up the counter man at a real pro paint shop. (Don't do this on a *busy* day or during the rush...) Read the product literature. Painting is complicated from a technical point of view **and** a highly developed skill. A skill that I wish I had <grin>
And use proper PPE (Personal Protective Equipment) as some modern finishes are fairly toxic (isocynate hardeners...).
Enjoy!
Dave
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