By Damon Lee
PHOTOS BY: Dan Ingham and the author.
Preparing a vintage car for a first-class paint job is no simple task anymore. After 30, 40, or 50 years of use, abuse, and often less-than-careful storage and handling, most of the vehicles we choose for custom projects require at least a little attention-be it rust repair, dent removal, or personalization-before they're ready for a new glass-smooth finish. More often than not, bodymen don't want to begin any of that work until every bit of old paint, body filler, and rust has been removed.
It used to be that only high-end restorations were thoroughly stripped to bare metal in preparation for paint, but the process has become common-place in the past decade or so. There are many reasons for this, the most obvious being that you never truly know the condition of any vehicle until you see it in bare steel. Many cars that look nice at first glance turn out to be hiding significant rust or damage underneath a quickie paint job and some body filler. Others show their need more blatantly, with faded paint and surface rust just begging to be stripped off. Even if you are fortunate enough to score a project car with original paint, chances are the finish is so chipped or brittle that you're better off removing it. Hey, you don't want any surprises coming back to haunt you after spending thousands of dollars on new paint, do you?
In the past, you had two options for -removing old paint-chemical paint stripper applied with a brush and scraped off by hand, or 80-grit sandpaper on a dual-action sander. Both methods still work, but many enthusiasts have found media blasting to be a better, more thorough, option. The process is often referred to as sand-blasting, although actual sand is rarely used in automotive applications because it is so abrasive and generates so much heat that it can easily warp sheetmetal. Various types or other abrasives, or media, are used instead-everything from plastic to baking soda to walnut shells. The softer media is much safer on sheetmetal, and usually requires less pressure (20-40 psi for plastic, compared to 85-100 psi for sand) to get the job done.
We recently made a trip to Hot Rods & Custom Stuff to see the company's Pro Strip media blasting system in action on a '57 Ranchero belonging to Custom Rodder publisher Del Austin. The entire blasting process was performed in a self-contained booth similar to a paint booth. Body and paint shop manager Mike Adams explained to us how the plastic media they use is considered a non-destructive stripping material-that is, it only removes substrates from the metal, without attacking the metal itself. In fact, Mike says, the plastic is so gentle that they use it on late-model vehicles and can remove paint without affecting the factory e-coat primer or galvanizing.
While the plastic is good for removing paint, body filler, and other materials that have a mechanical bond with the metal, it does not attack or remove rust. That's why the HR&CS crew uses a two-stage approach on many vintage vehicles. After removing paint and body filler with the plastic media, they go back over the vehicle and blast rust using a garnet material. While more abrasive than plastic, the garnet is still very lightweight; allowing it to be shot at low pressure. In addition to treating the rust, it also leaves the sheetmetal with a smooth, ready-to-paint surface.
With any blasting process, experience is key to doing a good job without damaging parts. Having the right feel and touch is just as important-probably more so-than having the proper equipment and materials. Josh Riley, who was at the controls for our demonstration, has many years of experience in media blasting, and more than three years of service at Hot Rods & Custom Stuff. Check out the photos and captions to see him in action.