EPISODE 4: THE DUAL CHALLENGES OF AGING AND ORIGINAL FINISHES.
In certain cases portions of the artifact no longer retain any original finishes, either due to deterioration or prior partial restoration. Other portions of the artifact that retain their original finishes are the first jumping off point.
The front portions of the original frame of Commander Perry’s 1963 Z06 not only retain much of its 54 year old factory applied paint, but more significantly, is one of less than 4% of all 1963 Corvettes to still retain its original frame stencil.
However, the bad news is that the further aft we get, the original frame finishes deteriorate and then no longer remain.
The tricky part here is that the original frame paint does not age with a uniform consistent appearance due to the original environment it inhabited.
A lesson now in original frame paints. Chevrolet subcontracted out the manufacture of the frame to the A.O. Smith Corporation and the A.O. Smith Corporation using Chevrolet’s required specifications, in turn, subcontracted out their source for frame “paint” with the Mortell Corporation. In 1982 your author contacted the Mortell Corporation and found that from 1963-1982 Chevrolet utilized 5 different coatings on the Corvette frame, none of which could be termed a true paint. In 1982 for example, the frame coating was a black paraffin based substance (think candle).
In 1963 the frame coating was a cut-back asphalt based coating that offered some corrosion resistance at a fairly minimal cost (think driveway). All asphalt based coatings are not created equally and they are produced in large cracking towers (think New Jersey) where the quality varies depending on where in the cracking tower you are.
Once the Corvette is assembled and driven, the effects of wear and time vary. The portion of the original frame that lives under the engine compartment will generally have its black frame paint smooth and well preserved compared to the aft portion to the rear of the firewall where the frame paint is usually greatly diminished from road wear and tends to take on a grainy rough texture.
In episode 5 we look at why there is a significant difference in the cosmetic appearance of the same frame paint.