Any whole-car paint removal project based on sandpaper if futile. Sorry to
be blunt, but you will be sanding for the rest of the millennium...
especially if you find a bit-o-bondo under the paint ( and you most likely
will) I think your efforts would be much better spent with a couple of
gallons of "AirCraft Brand" paint stripper ( NFI, but accept no other...)
Make whatever arrangements are needed to clear the nasty fumes, buy some
good gloves, a few assorted scrapers and a couple of cartons of coarse steel
wool. Yes, the stuff has all the nasty chemicals in it, but when you
compare it to the hazards of breathing in powdered paint dust for the next
year or so, it doesn't seem quite so bad. Also consider that this stuff
will remove ALL the paint in one or two applications, thus reducing your
exposure time...
Slather it on in a good gooey layer, and cover it immediately with a
layer of Saran wrap to reduce the evaporation of the solvents and enhance
the performance of the remover. It will keep the fumes down a bit, and you
can scrape the whole mess off with a metal scraper after an hour or so (it
is somewhat temperature dependant) and toss it immediately in the trash
outside the shop. A bit of touch-up will be needed, usually the steel wool
and a set of good gloves will do a nice job.
I know there has been some very credible criticism of liquid
removers, and yes, the good ones are toxic. But managed carefully, you can
minimize your intake and get a really thorough job. If you choose to use a
D/A sander, you will need to use Very coarse paper to make any real
progress. This stuff tears up the surface, causing "sandscratches" that are
really tough to eliminate with finer paper later. And if you don't remove
all the paint -right down to the metal- the coarse paper's sandscratches
will sometimes tend to show up in the finished paintjob, no matter how much
fine sanding and layers of sealer you use. This is called 'Sandscratch
Swelling', and it is caused by an interaction with the topcoat thinners and
the non-uniform surface ( those scratchy marks) that you thought were all
gone.
Your only other alternative is to have the car blasted with walnut
shells ( I am not making this up) or an abrasive plastic media. Using sand
or 'Black Beauty' grits can actually expand the surface 'texture' of the
sheet metal, and cause warping on large flat panels. Nearly impossible to
get them flat again, because you have actually expanded the surface of the
metal, while the underlying metal has stayed the same.
Taking a car down to bare metal is a big job, but sometimes the only
way to go. If you have deep defects in your existing paint (
'alligatoring', checkerboard patterns, etc.) then you have no choice. If
the surface is not too bad, you might be well advised to do some very
serious sanding, ( though not to bare metal) followed by primer-surfacer to
even up any remaining defects, followed by a good epoxy based sealer, to
minimize the sandscratch swelling which may develop. Trying to bury these
defects with Nitro-Stan (or equiv.) putty is futile, and never put any bondo
over old paint.
And I thought this would be a short note. Too much caffeine, maybe....
Good Luck!!
Bob Westerdale
59 3A TS36967
-----Original Message-----
From: Michael Ferguson [mailto:fergie@ntplx.net]
Looks like I may finally decide to bite the bullet and repaint my TR3A this
winter (or at least start the process).
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