Prime Time

Prepped as described, all that was required at the paint shop was to mask the car, wipe it down using paint prep solvent, and blowing it over with the primer surfacer in the paint booth. Jason Pecikonis at Timeless Kustoms in Camarillo, California, shot the Pontiac with multiple coats of PLC Poly Primer, an economical, high-build polyester-based primer-surfacer. The surfacer serves to build material thickness on body panels, allowing block-sanding to a very smooth and level surface. In essence, this primer acts as a filler, allowing the panels to be massaged to the flawless surface expected of custom paintwork. Just how closely the final result comes to achieving this goal comes down to the block sanding process. To aid in the block-sanding procedure, Jason followed the primer application with a light dusting coat of a contrasting guidecoat. The guidecoat will provide a visual progress reference as the primer is sanded smooth and level, calling out flaws in the bodywork as the car is sanded.

Getting primer on the car is a major milestone in the painting process, and the look of a consistent primer finish seems like a giant step forward. This is not a stage to get impatient, however, since the quality of workmanship in block sanding is going to have a direct affect on the quality of the finished paintwork. In fact, you might consider this the make-or-break step that separates an outstanding finish from the ordinary. The object here is to sand the car in such a way that the material thickness of the primer yields to make the body panels smooth and free of minute ripples. To achieve this, the sanding is done using specialty autobody sanding blocks, such as those available from Eastwood, which allow the primer to be cut flat and level along the body contour.

When it comes to sanding blocks, for the major expanse of the body panels, a general rule is the longer the better. A long board will average the minute ridges and valleys on the surface, cutting the primer to a dead-level surface. With the guidecoat on the primer, the process will visually unfold before your eyes. The higher ridges will clean first, while the slightly lower valleys will retain the guidecoat. In block sanding you’ll continue sanding until the entire surface levels out, as indicated by the guidecoat cleaning uniformly across the panel. Of course, if the flaws are more significant than the material thickness of the primer, it will never level clean before cutting through adjacent primer areas while sanding. This indicates the need for an additional primer coat, or even the application of filler in some instances. Sanding primer will reveal whatever flaws are present in the bodywork.

With his freshly primed LeMans back home, Sean began the tedious block sanding process, starting with 180-grit sandpaper on a long sanding board. When making the first cut to the primer, it is a mistake to start with a grit that is too fine. A fine paper will not have as aggressive a leveling effect, tending to float on the panel. To aid in getting razor-sharp character lines in the finished panels, tape was run at the line, and the sanding was done downward using a diagonal motion to the line. Reciprocally, once the panel is completed downward to the top of the taped character line, the tape is reversed to the opposite side of the line, and the panel is sanded upward in diagonal strokes to meet the line from the opposite side. This technique results in straight and crisp character lines, which are a pronounced feature of the LeMans.