From: Mil-Veh Co. (milveh@sbcglobal.net)
Date: Fri Mar 11 2005 - 13:28:34 PST
Maybe sandpaper isn't the most sexy subject in the
world, but when you are dealing with MV's I think it
can be a big help if you need to cut fast in a minimal
time.
3M has a fairly new sandpaper that doesn't clog and it
cuts fast. Not sure how they do it, but it really
doesn't clog-up unless you hit something wet or
greasey, then nothings going to help that. Lasts about
3X as long as regular paper and costs about 25% more,
but well worth it!
As most of you know, prepping a large truck or even a
small jeep can be a real pain when you are dealing
with many layers of old, old paint! After the first
few layers you can really appreciate something as
simple as good sand paper!
Next...
FYI, here's my method for prepping MV's for paint:
(WARNING: First thing, always use good breathing
filters for sanding CARC)
1. When dipping and stripping isn't practical, I use
80 grit and dry sand it. This gets the job done pretty
quick without striating the metal too much. Use
orbital sander (non-directional sanding), round or
square surface, air or electric, doesn't matter that
much, probably you'll use both round and square before
it's over.
3. When you get down to a smooth surface and have all
those pits feathered out least as smooth as meets
[your] standards, then its time to change paper to a
medium grit and feather them out some more! This
medium grit will quickly knock off the heavy sanding
marks and then you are ready use fine grit to really
finish it up. The fine isn't meant to grind off paint
so don't try using it for that. That just burns up the
paper. This is ONLY for making a few light passes over
things.
4. Use a good grade primer (cheap investment to last
paint job) AND....at least as "hot" as your paint of
choice. A good primer ought to have a rust inhibitor
too since your MV flat paint doesn't offer much rust
protection, some will say none, so primer is
important. I've heard some guys use semi-gloss to get
the rust protection, but a good primer probably works
just as well...least thats been my experience.
Speaking of primer, NEVER shoot enamel or water base
primer and come back later with a finish coat in
lacquer or your vehicle will look like a Jackson
Pollock painting!
I like working with lacquer for a primer, feathers out
nice and will take anything for a top coat, but if old
paint is being covered and you're not sure what it is,
better test lacquer out on a hidden area first to make
sure you don't get any curling.
5. Most commercially available MV paints are thinned
with acetone. This dries so fast you almost have to
try to get a run! I thin my paints just like the MFG
says, so don't get caught following some old rule of
thumb...could get messy! Like they say, when all else
fails read the directions!
6. Maybe this one should have been number 1, but I'll
throw it out here now anyway. Use a good de-greaser
and de-waxer before you sand. This is a commercial
product, don't cheap out and use Comet or liquid soap.
If you don't do this step you can push the
contamination into your old dead paint thru
sanding...not good, trust me.
7. Tack rags and taping. When you tape up windows
leave a little edge of 1/32th or so showing on the
rubber seals, don't lap masking tape onto a metal
surface that is to be painted. You don't want that
soft paint coming off unintended places with the tape.
A razor slice along the edge of the tape also works
well to prevent peeling, but this also could leave a
bad striations if you cut too deep.
A "tack rag" is a good way to pick up dust from your
sanded surface just prior to shooting. Available at
any paint store, cheap tool for a good finish job.
Bottom line: Take your time, 99% of a good paint job
is the prep.
Hope I wasn't too windy, but considering what there is
too learn I really only barely covered the basics.
Oh, and one last thing. I would NEVER shoot a car
using this method. Thats a whole different category
and involves lots of wetsanding by hand!
This archive was generated by hypermail 2.1.4 : Sat May 07 2005 - 20:41:23 PDT