How do I paint this 1957 Mercedes 300SL roadster?

[tomcolitt]

Hi

As a preface, I virtually (pun-intended) learned how to paint with the help of Len's video and this site. About a year ago, I painted my first complete car and this year that 1969 280SL has won 3 out of 3 Best in Class at some of the biggest car shows in Southern California. Thanks a lot for that.

Now I have been assigned to re-do a 1957 300SL roadster that was recently completely restored, but it has gotten so many nicks and little damage all around the car, that the owner has decided to have me completely re-paint the whole car. I think I will have a go at it. What I lack in skill and experience, I make up for in persistence.

Now, for my question: The 300SL has those famous "gills" (enclosed pictures) behind the front wheel arches and I can't figure out how they painted those without getting either a very course clear coat coverage or runs, etc. or without a visible transition zone, if they painted it in two sittings. I'm guessing they may have been painted from the inside before the body went back on the frame, but I definitely am not removing the body. By the way, the vent louvers do not come out of the body and it would be extremely hard to sand and buff in there if the clear didn't turn out very smooth.

That's why I am thinking about leaving the opening and louvers untouched and masking the whole gill opening about 1/2" inside the outer edge of the car and using feather tape or such to create a soft edge. I did my own car recently with some similar creative masking and "building" a kind of baffle to create a soft edge leading up to the roof line, making sure that I didn't shot the base coat quite as far under my baffle as the clear that goes on top of it. If you look a little closer you can see the transition and I also had the advantage of fading out into a body crease...

With the gills, I'd be fading into the horizontal and vertical walls of the square opening and I'm worried that even if I can blend the base coat nicely "around the corner", I will see a transition zone if the clear at least on the lower surface of the opening that is easily visible?... Keep in mind that I have very little experience, or great success with any kind of techniques that involve, slowly fading out the paint flow, reducing air pressure or using a highly reduced mixture of clear coat. But I'm willing to try it with a little guidance.

What do you guys think? I'm looking for 99% perfection and I will be using (I think) a light beige uni color Glasurit base/clear system.

Thanks, Tomtcolt@netzero.com

http://cid-b224b42440cc5480.skydrive...a7pmEmE7YTA%24

[Phil V]

That car in excellent condition is worth around $400,000.00 Just out of curiosity - what are you charging him to paint the car ?

[tomcolitt]

Wow Phil

You don't sleep much either.... Yes, they are worth some money, not sure if they came down from their highs these days, but the owner already has a lot of money into this restoration. I'm sure this job will take a lot of hours. Also, when you work on a car like this their is also a big risk to screw something up and since I want it to be a 96 or 97 point car, it could require some repeat work, although I hope this time I can keep myself from trying to get the clear so smooth that I cut through the clear this time. If you want, we can chat more off-line...

[Len]

That's pretty tricky for several reasons....

1. Whatever is behind the louvers needs to be protected.
2. The back of the each louver needs to be painted.
3. The opening that the louvers fill has a wide, painted edge that the louvers attach to.
4. "Blowback" can be a problem because you're blowing your paint into a pocket and pressure will cause the incoming paint to hit the air cushion and blow back into your face. A small HVLP gun would help a great deal because of the low air pressure needed to atomize the paint.

Like most of the paint jobs we do I'd raise the vehicle so that it's a little easier to view and reach in order to address these details.

After prepping I would mask then apply color and clear to the louver area. 3M Smooth Transition Tape would work well to frame the edge of this area and a small detail gun is a must to help insure an even application of materials.

One thing you don't want to do is to get a run in the louver area so I'd recommend applying the clear very conservatively allowing orange peel if necessary and allowing it to flash well in between coats. If necessary you could sand out the orange peel and apply an over-reduced clear (flow coat) for a final finish. Masking off the louver area to paint the rest of the car is going to be more difficult than painting the entire car first THEN painting the louvers so I would probably paint the louvers superficially when the car is painted then re-prep them, mask and shoot them last. In most cases I would paint the louvers first but because of the "inside" masking difficulty that I see in this case I would paint them last. Like I said previously, a detail gun (like the DeVilbiss SRi) is a must for this type of work.

[studebaker]

Len,
Would you go into more detail about the "over reduced" clear application?

[Len]

Len,
Would you go into more detail about the "over reduced" clear application?

Once you have clear on the surface you may have more orange peel than you want but it may be difficult to polish as in this area. If you wet sand to level the peel you can then over-reduce the clear with about 10% to 25% more reducer than normal and apply a couple of light coats. This will cover the sanding scratches and level the surface without adding much film build or orange peel.

[tomcolitt]

Hi Len

Thanks for the good idea. I especially have to think about raising that whole car...I actually only rent a spray booth...

I think maybe you missed that this was a complete new paint job a few months ago and the whole louver section is already painted and has no damage. Also, there is no way to shot the back of the louvers without the car off the frame. That is why I was thinking that maybe it would be possible for me to not paint that whole "louver box" and somehow blend the exterior paint job around the edge, into the louver box? In that case, I'd set up my transition tape in two rows (the first for the base coat and the second for the clear) so that the new paint coat just wraps around the edge of the box. Or would I be better off masking only the vertical louvers and repainting the whole inside box section that frames the louvers? Would this scenario change your approach? By the way, would specialty problems like this and others, I'm sure you come across, be a good subject for another spray painting tape?....

Thanks, Tom

[Len]

Hi Len

Thanks for the good idea. I especially have to think about raising that whole car...I actually only rent a spray booth...

I think maybe you missed that this was a complete new paint job a few months ago and the whole louver section is already painted and has no damage. Also, there is no way to shot the back of the louvers without the car off the frame. That is why I was thinking that maybe it would be possible for me to not paint that whole "louver box" and somehow blend the exterior paint job around the edge, into the louver box? In that case, I'd set up my transition tape in two rows (the first for the base coat and the second for the clear) so that the new paint coat just wraps around the edge of the box. Or would I be better off masking only the vertical louvers and repainting the whole inside box section that frames the louvers? Would this scenario change your approach? By the way, would specialty problems like this and others, I'm sure you come across, be a good subject for another spray painting tape?....

Thanks, Tom

Ok, so you're NOT painting the louver area but you're painting the rest of the car? I would carefully cover the louvers with masking material up to about 1/2" from the edge of the box then apply my Transition tape then bridge the space between my mask and the tape with a piece of 3/4" masking tape. This will allow you to remove the Transition Tape and 3/4" tape while the paint is still wet.

I've never used two pieces of Transition tape so I don't know how that would work. I would probably go with one piece and polish the edge when I'm finished.

If you don't have a lift in the booth you may be able to jack up the car and put it on stands for painting. That's a lot easier than crawling around on the floor trying to apply your paint evenly. My lift crapped out a while back and I've been using stands and it works out well.

[tomcolitt]

Thanks Len

The problem I have had when I use one piece of transition tape with a base coat/ clear coat system is that the resulting transition area is very narrow and when I color sand and polish that, there seems to be no guarantee that the paint droplets that travel the furthest underneath the transition tape will be covered by clear droplets too. So when I polish that area, I obviously am polishing away clear particles in that transition band. That leaves some base coat in the transition band that isn't covered by clear and therefore has a different appearance and forms an irregular line in a certain light. Is there a way to overcome this? (I have tried this several times with metallic colors, maybe it isn't as much of a problem with uni-colors, but I would think it would still be affected?....

Tom