"Matthew P. Cummings" wrote in message gray.net...
On Fri, 16 Jul 2004 01:58:52 -0400, jls wrote:
What's the weight penalty for not stripping an old 172, just painting over
the old paint, after sanding it first, of course. I'm new at this but
willing to make a go of it. I'd like to use a high-gloss polyurethane and

It depends on what paint you use, but I'd guess 10 - 15 lbs would be added
to the plane.

Fact: the W&B done after a 2nd coat was added to our plane, is 30 lbs
more. Our plane probably has less painted surface area than a C172
(same max gross weight, I think the wings are shorter, more window area).
We would welcome having that 30 lbs back, believe me.

And of course, if there are any flaws in the underlying finish where
it is not simply weathered, but is not adhering properly or has a lot
of silicon impregnated through it from extensive use of silicon-based
waxes and polishes, those flaws will reduce the life of the 2nd coat.

FWIW,
Sydney