On 12 Feb 2005 08:27:16 -0800, (Stuff)
wrote:

Hello,
I want to repaint a few aluminum panels from the 60s. The panels still
have their original paint on them, but they are all scratched. They
are about 2 x 1 foot each. I have a can of new lacquer of the color I
want.
How do I prepare the surface properly, considering that the old paint
was probably applied professionaly with all sorts of wacky chemicals
that are no longer available?
I want to keep whatever base is under there so I don't expose the
aluminum, and just get that surface ready for the new paint.
Also, the look is important, they are very smooth and the the paint
looks very flat, no lumps or bumps.

If you don't want to expose the aluminum, removal of old paint isn't
on. Shoot it with a sandable automotive primer, wetsand with 400
grit wet-or-dry and a block to get a glass-smooth surface. The primer
will fill in the scratches and you'll remove the overburden when
sanding. It goes pretty fast; it only takes about an hour to
wetsand an entire car. If the scratches are deep, you may need to
glaze the divots with nitro putty and wetsand level.

It's hard to get lacquer to completely level, even on a well-prepared
surface. There'll always be a bit of orangepeel. That's why lacquer
finishes are usually rubbed out.