Author Topic: repaint: over old paint or bare metal ? single stage or base/clear ?  (Read 10357 times)

GGR

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Hi all,

this is for my W111 Coupe, but my Pagoda will follow the same path when its turn comes.

My Coupe is daily driver and is non metallic maroon. It had an older single stage repaint 10 to 15 years ago. Paint is faded but is holding well. It is still very nice when I buff it but it does not stay shiny very long. I want to repaint the car because I have a few rust spots and dings I need to repair. I don't want a show quality finish as I would like the paint work to blend with the nice patina of the interior. I would like the car to look like a nice 3 to 5 years old used car when I'm done, not like a car coming out of the factory with a used interior. In short, I would like the paint to have some "patina" as well.

I've read and asked around and some say I need to go back to bare metal to do a quality job, some say I can respray over the old paint if it's holding welll. It will save some work and potentially some problems due to flash rust. They say nothing holds better that original factory paint so no need to remove it. Just use a good sealer first to avoid chemical reactions. I'm tempted to go that way over the bare metal option.

I also read that single stage paint looks more like the origginal finish and is easier to touch up in case I get some dings. But the paint is a bit more difficult to buff and maintain over time. bc/cc has a better shine and is easier to maintain. I'm tempted to go single stage as it sounds to me the look will be closer to original and it may be easier to obtain some patina than wiith bc/cc.

Thanks all in advance for advice and for sharing experience!

George Des

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Re: repaint: over old paint or bare metal ? single stage or base/clear ?
« Reply #1 on: January 11, 2012, 13:43:31 »
This is always a dilemna when painting a car. When I did mine, I wanted to make sure that there was nothing hiding underneath a previous respray (20 years old) and the factory finish so I went the bare metal route. I did all the stripping using a variety of methods.  I only had some rust in the lower front quarter panel areas forward of the door and the front valence. These were all easily repaired by mig welding in repair sections. So, I'm glad I did the bare metal, but it was a real chore! I've heard the same regarding painting over a factory finish using a sealer--there is no better primer provided there is nothing lurking underneath. As far as the choice between single stage and bc/cc--the single stage will probably look more original than a bc/cc depending upon how much you color sand and buff after the spray job. If all the orange peel is buffed out on either, they will look almost identical. The original synthetic enamel finishes were baked on an always had some degree of orange peel. For more info on these kinds of issues, take a look at Len Stuarts autobody website. Hope this helps.

George Desiderio

BaronYoungman

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Re: repaint: over old paint or bare metal ? single stage or base/clear ?
« Reply #2 on: January 11, 2012, 16:11:04 »
I am by no means an expert but I have sprayed alot of my own vehicles over time and find that if the old finish is good you can sand down to the original primer then seal it and spray over for a very good finish, once you try to get down to the metal the job grows exponentially, I have always used a 2 step (color then clear) because the clear is much easier to get a high gloss finish and any enviromental damage (read bird %$#^@) does not effect the color of the underlying color coat.  I have never done the last clear coat myself I have ALWAYS had a professional spray that last coat for the mirror like finish.  Remember that originally on our cars would have been a laquer paint which because of the EPA is no longer available so using the one stage Acrylic enamels we have today will never get that some patia as the laquers did
Bob
just my 2 cents
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stickandrudderman

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Re: repaint: over old paint or bare metal ? single stage or base/clear ?
« Reply #3 on: January 11, 2012, 21:59:12 »
Budget will have a lot to do with it if you're not doing it yourself. It's a lot more work to go back to metal and then when you do you're pretty much guarenteed to find some remedial work required which wasn't noticable before.
You'll also find that after a few resprays swage lines and panel edges start to lose there definition becuase of the excessive paint build up.
Horses for courses really.

George Des

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Re: repaint: over old paint or bare metal ? single stage or base/clear ?
« Reply #4 on: January 12, 2012, 00:27:09 »
Actually, the lacquer paint jobs on Mercedes of our era were by special order only. The majority were painted with a synthetic enamel that could not be color sanded. You basically "got what you shot" with this until it was baked on an allowed to flow out to give the gloss. You could get this same enamel in an air drying version from one of the original MB suppliers, Glasurit, up until a few years ago--it was Glassomax 20 line. Many refinishers did not like to use it because it went on like marshmellow, took a long time to dry and required a super clean shooting environment to ensure no trash in the finish since it too could not be colorsanded. Paint has come a long way since and any of the major manufacturers like Sikkens, Glasurit, PPG and DuPont can provide products either in BC/CC or single stage that are far superior to the earlier finishes in terms of durablity and gloss

steves sl

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Re: repaint: over old paint or bare metal ? single stage or base/clear ?
« Reply #5 on: January 12, 2012, 02:40:11 »
I was a Body Shop Manager at a local Cadillac Dealer 20+ years ago. We had a paint thickness mill gauge, if the exsiting finish was above a certain amount, if my memory is correct it was about 10 mills, we could not guarantee the repaint, unless the vehicle was stripped to bare metal. Stop at local Body Shop and ask if they have a paint mill gauge, and ask what the current paint manufactures recomend. Just my 2 cents worth.
S. Schlaefer

Garry

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Re: repaint: over old paint or bare metal ? single stage or base/clear ?
« Reply #6 on: January 12, 2012, 03:06:18 »
The mil gauge is also a very good way to check for bog/fill in the panels as well by running it over the different areas.
Garry Marks
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GGR

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Re: repaint: over old paint or bare metal ? single stage or base/clear ?
« Reply #7 on: January 23, 2012, 16:54:46 »
Thanks all. This was useful. I think I will not go to bare metal and I will use single stage.

Thaanks again.