Hi there fellow LBC-ers,
Reading the thread on Valspar and on painting a car with a brush,
I thought I'd offer a few comments from my experience working in
marine refinishing for the past 10 years.
IT IS POSSIBLE TO GET A MIRROR SMOOTH FINISH WITH A BRUSH!
(sorry to yell, but that's for all those scoffers out there who
snicker at the thought of a pro quality paint job for under
50 bucks). Admittedly much of my experience has been on wood
and fiberglass, but once you get a couple coats above the primer,
your substrate no longer matters.
The basic technique is called "tipping" and there have been several
articles on it in Wooden Boat magazine and other marine trade
publications. I believe the Taunton Press (publishers of Fine
Woodworking and Fine Homebuilding) carry books on the subject.
The basic idea is that you apply an even coat of paint using a
low nap foam roller and then lightly "tip" out the paint with a
brush to remove the bubbles and to smooth the texture. The
equipment my parents shop has settled on using are the yellow
foam rollers with foam about 1/8" thick, and those cheap 39cent
2" foam brushes with the wooden handles. The rollers can be cut
to whatever size roller frame you plan to use; we usually use
3 or 4" frames and have to cut the 7" rollers to fit. You can get
some cheap disposable 3" metal frame rollers but the wheels on
the ends of those have been known to leave lines in the finish.
We have tried more expensive brushes, both bristle and foam, as
well as different sizes. 2" really works the best. Never save the
brushes as they will accumulate dust, and due to the economy of
the equipment, you can change brushes and rollers several times
at convenient points to reduce dust even more.
You should use a marine paint that was made for this technique.
Petit Easypoxy (a mono-urethane) and Epifanes Monothane are some
of the best and most durable. Also be careful to choose a metal
primer that is compatable with the finish coat, and tint the
primer to match the final coat color. Proper surface preparation is
essential. Be sure the entire car is free of dust and you have given
at least 4 hours since you last vacuumed the dust off the car.
Use tack cloths (those sticky cheesecloths used to pick up dust)
religiosly and go over the car several times, switching sides and
cloths as necessary. It's also best to work at low humidity and
at low temperatures, preferably below 50 degrees F (yes, even though
the can says 70) in order to ensure full flowing.
What you want to do is to roll out a small section about 8" wide
on a convenient section of the car. You'll have to plan this strategy
carefully because you want to always leave a "wet edge" that you can
use as the start of the next section, in order to reduce the possibility
of these sections showing after the paint dries. So you start at the
nose, at the headlight and carefully apply the paint with the roller
going about 8-10" aft on the car, being sure to apply a consistent
not-too-thin, not-too-thick coat. This can only be judged after lots
of practice, so practice with your priming coats and on some small but
challenging pieces that you can strip and do again. Immediately after
the roller, either you or your painting partner with just a little paint
in the brush follows behind lightly tipping (smoothing) the paint and
getting any areas that could not be accessed with the roller. Tipping
should be done in a consistent direction, usually back to front if you
are rolling from the front to the back of the car. Note that the roller
direction and the brush direction the either be parallel or perpen-
dicular. Then the roller is used again to go another 8-10 inches over-
lapping the previous region by about half each time. Follow again by
tipping, ad infinitum. For tricky areas, you will still have to resort
to traditional brusing. I recommend applying paint to the tricky areas
with a brush first, then using the roller as close around the area as
possible, then tipping over both the roller- and brush-applied sections
to ensure a proper blend.
This is not a technique that you can pick up in a weekend, (similar to
many things about Brit car maintentance). Read some, but practice,
practice, practice makes all the difference. Find a neighbor with a
Bondo-ed Nova, try it on your home woodwork, etc. Get used to the feel
of the equipment and paints. Learn to anticipate when it will run
or sag, know when to walk away and pop open a Sam Adams. You can
always strip it an try again :-). Of course if you have access to a
$10k spray booth all this is moot anyway.
As with any technique, sprayed or brushed, you will have to follow with
appropriate wet sanding and buffing to get the true mirror finish.
Criticisms, disparaging comments, etc. directly to me please.
-=- D. J.
-=- hagberg@ccit.arizona.edu
PS, speaking of those comments about the MG rally car V6, has anyone
tried to fit a Mazda MX-3 V6 into a Midget? That's on my list of
"dream projects"...
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