Basecoat/clearcoat vs. single stage?
 

Hello,

Have a black hardtop for my red (signal red - code #DB568) 1990 300sl.

I'm going to paint it myself but have a question on paint types.

What year did MB switch from the "single stage" paint to "basecoat/clearcoat"? Paintscratch.com says "most" manufacturers switched in around 1986 or 1987.

I can get that color code made up in single stage paint. Is there any reason I can't do it single stage? I'm relatively new to painting and don't want to screw up the job by adding a bad clearcoat to a good base coat! I'd rather just put on a few coats of single stage and call it done!

Hardtop is on the car 7 months of the year and is covered by snow for 4 months of that. If the gloss of the paint is different between hardtop vs. the rest of the car, that's OK. It just can't be TOO blatantly obvious.

Thanks!
Neal

There wasn't one year that they switched over - it was a gradual process over the 70s, 80s and 90s. Some non-metallics were single stage well into the 90s. Non-metallic black (040) was single stage from the early 50s until about 2 or 3 years ago. If you are talking 040 black for the top I would certainly go single stage. There's fewer components to buy, it's easy to put on, and I think it lasts longer, assuming you buy a high quality urethane paint. You don't really even need to be very good with the spray gun if you're willing work - wet sanding and buffing. You can get a perfectly flat, incredibly glossy result if you're willing to put the labor into it. That the great thing about single stage urethane - anybody can do it if you're willing to work. If it was the whole car the labor could be an issue but it shouldn't be that big a deal for just the top.

Thanks..

Should have clarified.. it's a black top now (either 040 or 199) and I need to paint it Signal Red. I am pretty sure the red isn't metallic so think I'll be OK with single stage.

As far as prep, what grade of sandpaper should I use? Wet or dry?

I've heard anything between 1000 and 2000 grit wet to prepare the surface. It's shiny paint now (excellent condition) but the paint won't stick until I dull it.

Not really interested in sanding to bare metal or anything, just dulling down the existing paint so the new will stick..

Thanks!
Neal

There is a misconception that the bond is mechanical, hence the need to sand heavily. The bond is more of a chemical nature. Whay I have done in the past is use PPG DP40 primer, PPG urethane hi-build surfacer, followed by sanding down to 600 grit wet, followed by thinned DP40 as a sealer, then a direct-gloss urethane (PPG Concept) top coat. Basic removal of silcone and waxes prior to knocking the gloss off the paint is all that is required.

Signal red is a base coat / clearcoat so if originality is important you should probably go that way. But there's no reason you can't use single stage if you can get the paint. I would normally use a 400 to rough up the surface but think 600 would work fine too. There's no substitute for a good retail auto paint store that's willing to give advice. But probably the most important thing is to pick a good paint, get the manufacturer's spec sheet on that paint, and then carefully follow the instructions.

Reds they ussually recommend base coat/clear coat because they hold up better to UV.
I'm seeing now base/clear/clear 3 part systems for reds.

Michael