Stumped on brillo pad like scratches 1981 Porsche 924

G

goldwolf

New member
Thrown a bunch of stuff at it. Using 3000 grit rupes wet discs on an orbital. It seems to make some improvement but never really appears flat and the scratches are still visible. Could the paint do this under the clear? Above the beltline it had some scratches, but those seemed to be a little easier. Do I just go to 2000 or 1000? Wet or dry? I do have a cheap paint gauge and the paint appears thick on the readings. My Saab and Honda paint measure normal with the same gauge.

Maybe an attempt was made to reclear? Idk, paint is super smooth after sanding, cannot feel the scratches at all. This my car btw. Any suggestions welcome!

bYTM0Co.jpg
ITeUfX0.jpg
Ghse6FP.jpg
5jDg7Z0.jpg





 
AFAIK that car wouldn`t have had clear from the factory unless Porsche was way ahead of the US mfrs who didn`t start using BC/CC until later in the 80`s. However, that does look to me like incipient CC failure, so I`m not sure I would be doing any more sanding on it. Nice car, how long have you had it? A few years ago I kept driving by a 944 that someone was trying to sell and thought about looking at it, fortunately someone else must have bought it.
 
Had it about 6 years. Got the mechanicals worked out, now onto cosmetics. I did some research and Porsche was clearing metallics back then. I am not real concerned about the clear, a repaint maybe needed anyway. The clear just seems incredibly hard and the scratches seem to be buried deep. Maybe hardening and cracking within.
 
How was it getting the parts? I used to know someone who had a late-80`s 930, and he needed a new wiring harness which he couldn`t get from Porsche and wound up having someone rip out the Motronic and put in an aftermarket system.
 
These are K jetronic, all mechanical fuel injection. Parts are a little tricky, but there is a good community 924board.org. There is even a guy building modern EFI kits for these now. This one is the Weissach edition, 400 made, mine is #179. Wiring in this one is pretty basic.
 
Have you tried correcting it with a Rotary???
How many microns are you getting on the scratches??? Over 100 ???
1,000 2,000, 3,000 grit is what is used after compounding...
Dan F
 
are you getting any color transfer on to the pads and rags? yes, if it has a clear and there is no paint transfer it would be under and would be magnified by the clear coat .. repaint would be the only answer
 
No color transfer, it is definitely clear coming off. Paint gauge was at .25mm I think, let me change it and check again.
 
The scratches are really just below the belt trim, and its like this on both sides of the car. hood and front bumper was painted in the past and the color match isn`t great, so its obvious. But doors and back just don`t look repainted to me, and its not thicker down low. But, the black rockers were sprayed at one point, there was overspray.

I don`t have a rotary.

Inside the door varies also, from 6 to 12 in some spots.
 
Maybe Porsche was putting on the paint really thick back then, but for cars built in this century, 16 mils would definitely scream repaint, I`m waffling a little on the 10 mils below the beltline, because maybe they put some heavy e-coat on back then for rust since that was before the days of galvanized panels, but even 10 mils, for a panel that you`ve been polishing is suspicious.

Maybe someone like Sizzle has polished one of these old Porsches and would have a better read on what a normal thickness would be. I think cars today are coming in at 4-5 mils, some years ago it was 5-6, I think 2 mils e-coat, 1 mil primer, 1 mil color, 2 mils clear was the "norm". Could have been different back when that car was built when clear was a new thing.
 
I`m not sure the galvanize is going to show up as part of the coating thickness, as I said, perhaps someone with better knowledge of these will chime in.

On a side note, interesting how far ahead of the domestic brands Porsche was with the BC/CC and galvanized panels. Maybe that shouldn`t be a surprise.
 
Goldwolf- I`d bet on it being a repaint issue, namely sanding scratches under the paint. After so many years it wouldn`t be unusual, and those (very) high readings seem right for that.

EDIT: Be careful comparing readings taken from doorjambs/etc., even on "high end" cars. I`ve had weird readings in out-of-the-way areas on Audis and Benzes (don`t recall ever taking readings there on my Porsches though).
 
goldwolf said:
That is the most logical explanation, just surprises me a little. But 36 years of unknown. I`ve had it for 6
Click to expand...

Heh heh, there can be all sorts of surprises on any car :D We discovered multiple areas on my Jaguar that were repainted *at the factory during the initial build*.

That`s such a neat car...I`m glad it has an appreciative owner. Is it tough to get parts for it, or is it another case of "it`s a Porsche, you can get anything if you pay enough"?
 
80% of parts are out there, but some big pieces are hard. Dashboard, carpet, not readily available. I need some replacement decals and they are hit and miss. Mechanical bits are fairly easy.
 
You must log in or register to reply here.
Back
Top