Aug 18 2010
Eastwood, the automotive restoration experts for hobbyists and professionals has a free tech library to provide do-it-yourself automotive restoration enthusiasts with information and solutions to solve simple and complicated auto repair and maintenance challenges.
In the category of automotive painting, Eastwood has produced a series of explanations about common spray painting pitfalls along with recommended solutions to those problems. "The best way to apply automotive paint applications is to spray it, whether using an aerosol can, an HVLP system, or compressed air and a spray gun," suggests, Joe Richardson, Eastwood's auto restoration expert and product development engineer.
Dry spray is a problem that occurs when partially dry paint spray settles over previously painted areas. Dry spray can also be caused by applying the paint too slowly or holding the paint can too far from the surface. Richardson suggests that the best way to repair dry spray is to sand it with fine-grit sandpaper, followed by compounding and polishing the surface, or refinish it as required.
Blistering, bubbling, pitting or a swollen appearance from a paint project occurs, according to Eastwood's free tech library, because of trapped solvents, painting over dirt or moisture or by rust that was left under the surface. "The easiest thing to do," Richardson recommends, "is to sand it down and refinish it. If necessary, sand it down to the bare metal and ensure that the surface is completely clean before repainting."
Automotive paint that drys too slowly, or was sprayed over wax, oil or grease, will not adhere uniformly to the surface being painted and it runs or sags. If the finishing coat is too heavy or the paint can or work surface is too hot or too cold, uneven surface coating occurs. "If the paint is still wet," Richardson advises, "use a camel hairbrush and brush out the sag and re-coat the surface. If the paint is dry, sand it with a fine grit paper, compound and polish it or simply refinish it."
An orange peel appearance occurs on the painted surface when the paint can has been held too far away from the surface, the spray nozzle is clogged or the shop temperature is too high. "For best results paint should be applied when temperatures are between 65F and 75F," Richardson recommends. Grit-sandpaper (600 or finer) and use a fine compound to rub out the ‘orange peel.’ If that fails, then the paint needs to be removed and the project needs to be refinished.
A small crater like blemish in the finish that looks like fish eyes occurs because the work piece was improperly cleaned or had silicone on the surface. If the paint is still wet, recommends Eastwood's Free Tech Library wash all of the paint off. thoroughly clean the surface and repaint it.
"We can often learn a lot from our mistakes," Richardson notes. "The good news with spray painting errors is that can often be fixed. And when you do, you probably won’t make the same mistake again."