Dirt Bike or ATV Plastic Restoration via Painting By Edward Pinzel on 4Strokes.com
4Strokes.com Technical: Plastic Restoration via Painting by
It is no secret that dirt bike plastic fades and gas tanks turn yellow as well
as lose decals as they age. Decals falling off and yellowing of gas tanks is
believed to happen as a result of fuel vapors escaping through the pores of
the plastic. After some good advice from others, this is what I have found that
works well for me. I have done about five tanks and lots of plastic, and they
all came out beautiful.
Although the directions below are geared more toward a plastic
fuel tank, they are basically the same for plastic fenders and number plates
(minus the first step and any internal prep and treatment).
Motorcycle Plastic Restore
Technical Article Sponsor
- Remove Petcock, tank mounting hardware, and gas cap.
- Wash tank with a good cleaner, like Castrol Super-Clean, both inside
and out. I use a skowering pad (like Scotch-Brite brand) to really rough
up the pores, using the cleaner and rinse out well with water. It is
advisable to use rubber gloves, as this cleaner sure can dry out your
hands. If there is varnished old fuel in the tank, an automotive grade
acrylic lacquer thinner or Acetone should be pored inside the tank to
loosen up the deposits. I shake the tank vigorously then empty the solvent
into a plastic container.
- Now wash the outside of the tank with acrylic lacquer thinner or Acetone.
I use a parts brush in a large plastic container. What was left over
from the above procedure should work fine. This is to remove most of
the old decals and adhesives, as well as any remaining grease or grime
in the plastic pores.
- The tank should now be flushed with soapy water, both inside and out,
and repeatedly rinsed with clean water.
- It is now time to sand the tank. I use an orbital auto body sander
(dual action or DA sander) and start with 80 grit on the deep scratches
and gouges, if there are any, as well as to remove old decals. I then
take 180 or 220 grit on the sander and do the rest of the tank, as well
as the areas that were sanded with the 80 grit, in an effort to minimize
the scratches. Try to keep the sander flat at all times.
- A skowering pad is then used on all the edges, the undersides, and
any areas missed by the sander, to promote adhesion for the top coating
- The tank should now be blown off with compressed air. Then washed
again, both inside and out, with soap and water and thoroughly rinsed.
Allow to air dry completely.
- Wipe the tank down with automotive grade wax and grease remover and
use a tack cloth (automotive grade) to remove dust particles. The tank
should now be ready for top coating.
- A product that I highly recommend for promoting good adhesion to plastic
parts and personally know works very well is Sherwin Williams # UPO7227
Adhesion Promoter. This is available in aerosol spray cans as well as
quart cans. The adhesion promoter should now be applied. I apply 1-2
wet coats, and let dry for about 30 minutes. I was able to do 4 tanks
with one 16 oz. aerosol can.
- You are now ready for the priming process. I used a flexible primer
manufactured by SEM. It is available in quarts and possibly aerosol.
The SEM part number is 39134 and it is called Flexible Primer/Surfacer.
This is a great product and builds nicely. It can be sanded after 45
minutes. I apply at least 2 heavy coats, let dry, then wet-sand using
220 grit wet/dry sandpaper.
- The tank should now be thoroughly rinsed and dried. Apply another
1-2 good coats of SEM # 39134 Flex-Primer. Let it setup (dry) then wet
sand using 400 grit sandpaper. Thoroughly rinse again, and assess your
work. It is possible that the tank may need another application. If
so, repeat as necessary, final sanding with 400 wet. When finished,
rinse the tank again thoroughly, both inside and out, and let dry. On
my original Can-Am MX-3 fenders (red fenders in photo below), I had
to perform the priming/filling process 3 times to remove all the scratches,
as one of the fenders was really bad to begin with.
- You are now ready for top coating. Remove any oils from handling using
wax and grease remover. Use sparingly as to not saturate the current
layers you have finished thus far. Make sure the tank is completely
dry. Now wipe using a tack cloth to remove dust.
- Any places on the tank where bare plastic is showing, where the SEM
primer has been sanded through, should be covered lightly with the UPO7227
Adhesion Promoter. There is no need to cover the entire tank again with
the adhesion promoter but it wont hurt if you do.
- Allow to dry. Tack dust again using tack cloth. Now the color is to
- I have always had good success using Sherwin Williams automotive finishes.
I use Sherwin Williams acrylic enamel with hardener for most plastic.
Now select the paint color of your choice.
- The Sherwin Williams acrylic enamel should be mixed as stated on the
can, using 8 parts color, 4 parts reducer, and 1 part hardener or catalyst.
The following additive should also be added: Sherwin Williams Multi-Flex,
Flex Additive, # V6-V299. Two parts should be added to the mixed paint.
Ensure you are using an OSHA approved paint mask, as the mixed paint
contains volatile chemicals, including Poly-Isocyanides.
- I generally apply 3-4 good coats to ensure full coverage, obviously
allowing the paint to flash between coats to minimize sags or runs.
- The paint should be allowed to dry completely. I generally wait 2-4
weeks, then apply the decals. The finished tank can be washed and waxed,
and cared for like any automotive finish, but waxing should be done
only after about 4 weeks time, so any remaining paint vapors are allowed
Here are some pictures of Edward's plastic restorations (click
We asked Edward how the gas tanks were holding up after a long
while and here was his reply:
"The finish holds up incredibly well, as it is an automotive
paint re-finishing system. There are sealers to seal the insides of these tanks,
and they will work well for preventing the gas fumes from trying to escape through
the plastic pores of the tank. When the fumes try to escape, from leaving the
gas in the tank for prolonged periods of time, there is a bubbling problem that
is created near the bottom of the tank. I have done many tanks in this manner,
and the ones that have a good tank vent, and are drained and flushed with water
after riding seem to last the longest. Those that leave gas in the tank without
sealing the inside seem to bubble near the bottom. Those that seal the inside
of the tank seem to last the best, and the finish on the tank is as durable
as any finish on any automobile, as automotive refinish products were used to
restore the plastic above."
Credits: Article and photos produced by Mr. Edward Pinzel of Clearwater,
Florida, and edited by 4Strokes.com.
4Strokes.com Technical: Main