Arc & spot welding
Automotive hand tools
Car enamel colors
Car paint colors
Car paint glossary
Car painting problems
Cleaning car upholstery
Infra-red paint drying
Interior automotive trim
Painting over paint
Paint surface preparation
Refinishing paint tips
Safe car spraying
Sanding, striping, rubbing
Shrinking sheet metal
Not finished yet:
This condition is usually found where the finish forms a center line on cowls and turret tops. If left side of car is painted first, overspray appears to left of center line when right side is sprayed—or vice versa. At this point, gun is held at angle and farther from surface than at other points of stroke.
To overcome, spray side of car on which overspray appears with a wet mist coat. A mist coat is made by adding several parts of thinner to the color left in the cup, or it may be a straight coat of a good thinner.
Rust under film
Caused by presence of rust on surface before finishing—and no paint will adhere to a rusty surface. To avoid this, always sand all rust spots bright and treat bare metal with a metal conditioner such as "Deoxidine," "Metalprep," etc., before finishing. Wash with water and dry thoroughly. Always prime the surface immediately after cleaning, as rust will set in if bare metal is exposed too long.
Wrinkling of Dulux
Always follow recommended procedures when reducing and applying successive coats of Dulux, and always add RK-5756 to 93 Line if film is to be force dried.
Finger prints showing
This blistered outline of finger prints shows what can happen when bare hands touch any surface about to be painted. No matter how clean the hands may seem, there is almost always some dirt, grease, oil, or perspiration which will cause blistering, rust, and poor adhesion. Keep bare hands off the surface!
In automobile plants, bodies are never directly touched with human hands after being chemically cleaned—the operators wear cotton gloves. It's a good practice for ALL painters to follow!
Runs or sags
Pinholing in lacquers
Chalking of lacquers
The left section of this panel, which was exposed on a paint farm, shows (in comparison with an unexposed section on right) what happens when a finish chalks. A natural failure, chalking is the gradual breaking up of the film under weathering and exposure to the sun's rays. It results in a gradual loss of gloss and powdering of the surface.
When this condition is encountered, rub and polish the surface to remove "dead" pigments and get to the "live" film beneath. Then wax the finish to protect and prolong its life. The use of a mist coat mixed with a slower-drying thinner on a finishing job will enable the film to set better and aid in retarding chalking.
Rough, dirty finish
This condition results from applying lacquer type products over unaged air dry synthetic finishes. It also results from applying a finish over a surface from which old wax, grease, or polish is not thoroughly removed. To avoid the latter, always clean the old surface with Prep-Sol to remove wax, grease, polish, and other foreign matter before any sanding is done. Improper recoat time may also cause lifting.
Shrinking and splitting of putty
Because putties usually dry quickly, they may shrink, split, and remain soft when applied too heavily, as shown by this close-up.
Apply several light coats with a glazing knife or squeegee, allow to dry between coats.
If you apply finish over a waxed surface you encounter a difficulty as illustrated on the panel shown here—in this case wet spots which spoil the job. To avoid this, use Prep-Sol as a cleaning agent to remove wax, grease, and polish from the old surface.
Crazing, cracking, and checking
These conditions, each a degree of the other, result when: