wet sanding an old corvette

[mirrorfinishman]

The paint on an old corvette shows visible signs of stress cracking. The car is a white 1969 and it was repainted sometime in the mid 70's using the same color and type of factory lacquer paint. I believe the original paint and the repaint were both made by DuPont.

Now if you have ever seen anything like this, you will know that the stress cracks are hardly noticed until you get into an exact angle of light. Actually, the car looks like a brand new car from a few feet away at most other viewing angles. The cracks appear to be on the surface as you can actually feel them with your fingernail. Also, the stress cracks appear to be more concentrated to the hood, roof and rear deck. The sides are relatively good.

In an very small inconspicuous area, I tried using a polishing pad and an agressive compound by hand. I was somewhat surprised to see that the cracks appeared to be almost completely removed with very little effort. So I am now wondering what the results might be going with a wet sanding process.

Any comments on wet sanding an old repainted corvette?

[Accumulator]

IIRC the paint they were using on 'vettes back then is basically the same as the single stage acrylic lacquer on my Jag (which also has a few cracks, just the nature of the stuff).

It can be tricky to tell the actual cause of the cracking on 'vettes due the fiberglass...stress, normal wear/tear, "lacquer checking", lots of things can be to blame.

I wouldn't wetsand it myself. I'd rather have thick but imperfect paint than thin but closer-to-perfect paint. I'd just use the typical abrasive products (as you've discovered you can use pretty aggressive stuff on white ss) and then a good application of a pure polish like #7 before you LSP it.

I'm just a nut about preserving older stuff in the most gentle way possible...even older redone stuff. I'm far less hesitant to wetsand modern b/c paint compared to older stuff.

That sounds like a neat job :xyxthumbs Bet you're enjoying working on it.

[the other pc]

It's normal for checking (a.k.a. cracking, crazing, spitting, alligatoring, crowsfeet) to be more concentrated on the hood and horizontal surfaces. The hood goes through the greatest extremes of heating and cooling. All horizontal surfaces get the most environmental abuse.

The only way to repair paint checking is to sand it down to the primer (or base panel) and spray new paint. (I'm not sure what to do if it's in the gelcoat, maybe grind it out and apply a coat of body filler?)

Sorry, you'll have to decide if you'd rather live with it or get a new paint job.


PC.

[mirrorfinishman]

Noticed something rather interesting the other evening at a local car show/cruise night. While the sun was still out the painted finishes on just about every car looked great. Not a flaw or imperfection to be found. However, as soon as the sun went down and the lights in the restaurant's parking lot came on, it was an entirely different story. You would have been amazed to see all of the paint defects that became visible as the lights reflected in the finishes.

[Accumulator]

Mirrorfinishman- Yeah, lighting can make all the difference. I believe you and I have discussed this over at another online forum...I use high-wattage incandescents in an otherwise dark shop to simulate the kind of lighting you saw at the show. I forget the technical details, but it's something like "point source" lighting and the "dark field" effect from no other lights makes all the difference. It's the only way I can see light marring on colors like silver (at least in a shop environment).