What's the undercoating on the air cooled cars?
07-06-2008, 01:59 PM
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What's the undercoating on the air cooled cars?
I'm trying to find the name or product Porsche uses to coat the inside of the wheel wells of the 87 (or probably any of the 70's-80's air cooled cars). It's black and appears to be some sort of posssibly petroleum based product....I was a little over zealous on cleaning out one of the wheel wells and was informed that Porsche deliberately put some sort of black coating in the wheel wells rather than leave them the color of the car.
Can you tell me what that product is so that I might re apply it to those areas where I've scrubbed the coating off? It seems to be a rust protectant...not the cosmoline you see on the underside of the engines.
Can you tell me what that product is so that I might re apply it to those areas where I've scrubbed the coating off? It seems to be a rust protectant...not the cosmoline you see on the underside of the engines.
07-06-2008, 06:39 PM
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07-06-2008, 08:31 PM
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I doubt you'll ever find the exact product they used 21 years ago.
Whatever it was it didn't come in puff cans either.
Factories and body shops use pro grade undercoating stuff that comes in containers up to a 55 gallon drums.
One major USA brand is 3M, and there's is called body shutz. It is sprayed on with a special large nozzle spray gun made for it.
If you want to do it yourself you can buy similar stuff from 3M in puff cans. While spraying it, instead of sweeping back and forth like spraying paint it goes on more uniform if you go around in small circles overlapping and not stopping till you're done to get the best look.
Holding the can close to the surface and moving the can quickly will give a wet coat that dries smoother while holding it farther away, it will start to dry as it flies through the air and goes on drier leaving a more pebbled orange peel finish.
If you've never done it before then best to practice on some cardboard so you can see what the texture will look like.
Most important is don't put it on real heavy and thick or you'll get a sagging mess that looks like it is boiling from solvent retention below the skinned over surface.
If you like to wax your own car then one way to keep overspray from sticking to your paint is, put the wax on your car, then spray the undercoating on then wipe off the wax. Any overspray on the paint will wipe off with the wax.
This trick works real well when spraying headliner paint on a headliner to keep that overspray from getting on the paint. I leave the windows open when doing that and it works real well.
Clean up with mineral spirits or laquer thinner.
Whatever it was it didn't come in puff cans either.
Factories and body shops use pro grade undercoating stuff that comes in containers up to a 55 gallon drums.
One major USA brand is 3M, and there's is called body shutz. It is sprayed on with a special large nozzle spray gun made for it.
If you want to do it yourself you can buy similar stuff from 3M in puff cans. While spraying it, instead of sweeping back and forth like spraying paint it goes on more uniform if you go around in small circles overlapping and not stopping till you're done to get the best look.
Holding the can close to the surface and moving the can quickly will give a wet coat that dries smoother while holding it farther away, it will start to dry as it flies through the air and goes on drier leaving a more pebbled orange peel finish.
If you've never done it before then best to practice on some cardboard so you can see what the texture will look like.
Most important is don't put it on real heavy and thick or you'll get a sagging mess that looks like it is boiling from solvent retention below the skinned over surface.
If you like to wax your own car then one way to keep overspray from sticking to your paint is, put the wax on your car, then spray the undercoating on then wipe off the wax. Any overspray on the paint will wipe off with the wax.
This trick works real well when spraying headliner paint on a headliner to keep that overspray from getting on the paint. I leave the windows open when doing that and it works real well.
Clean up with mineral spirits or laquer thinner.
07-07-2008, 03:45 AM
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Thanx JF....I'll give that a try on some cardboard to see if I can "match the hatch" so to speak....I dont have a lot of area to re-do, but I do want it to look stock. Even if it doesn't stay on there quite as durably as the original, there's not much to pulling the front wheel, masking it off and re spraying it.
07-07-2008, 10:10 AM
#6
Burning Brakes
Chuck,
If your wheel wells are black then they have probably at some point been sprayed... or should I say resprayed. The wheel wells of these cars should appear body color once cleaned. That is how they arrived from the factory. Porsche unndercoated the cars then sealed with paint.
Most undercoating or shutz is petroleum based to some degree. The closet match you will find to what the factory used is mad by Wurth. You will also need they're "special" gun to spray it with unless they've finally become curtious and decided to offer it in a spray can.
How that helps you...
Paul
If your wheel wells are black then they have probably at some point been sprayed... or should I say resprayed. The wheel wells of these cars should appear body color once cleaned. That is how they arrived from the factory. Porsche unndercoated the cars then sealed with paint.
Most undercoating or shutz is petroleum based to some degree. The closet match you will find to what the factory used is mad by Wurth. You will also need they're "special" gun to spray it with unless they've finally become curtious and decided to offer it in a spray can.
How that helps you...
Paul
07-07-2008, 03:30 PM
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I went to the Wurth website and saw that they were offering it in a spray can...I guess my only question is that if it takes a special spray gun to apply it....they must have had to thin it out quite a bit to get it to come out of the nozzle on a spray can.....but if that's what they used, then I guess that's what I'm going to try......like JF said...try it on a piece of cardboard first and see how it applies.
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07-07-2008, 04:25 PM
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3M makes the type that goes on under paint too. They used to call it rocker shutz instead of body shutz. I've never seen it in a puff can, but maybe it is available that way.
It is nuetral colored... or creamy yellow colored and it is used on lower rocker panels on many cars including 911's under the finish paint to lessen the occurance of stone chips blasting away the paint there.
There is also a product called seam sealer. It is a brush on goo that dries but remains pliable that goes over seams where body panels are spot welded together. You can see the brush marks where it has been applied.
I don't think you'll see any visual difference between Wurth and 3M products in this application.
Wurth doesn't actually make the stuff, they just mark up the price and distribute it.
3M makes there own stuff, will cost less, and is probably higher quality in my opinion.
There are other brands that cost less than 3M and work very well too. Go to a body shop supply place and check out your options.
It is nuetral colored... or creamy yellow colored and it is used on lower rocker panels on many cars including 911's under the finish paint to lessen the occurance of stone chips blasting away the paint there.
There is also a product called seam sealer. It is a brush on goo that dries but remains pliable that goes over seams where body panels are spot welded together. You can see the brush marks where it has been applied.
I don't think you'll see any visual difference between Wurth and 3M products in this application.
Wurth doesn't actually make the stuff, they just mark up the price and distribute it.
3M makes there own stuff, will cost less, and is probably higher quality in my opinion.
There are other brands that cost less than 3M and work very well too. Go to a body shop supply place and check out your options.
07-07-2008, 05:18 PM
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Burning Brakes
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Awhile back I had to replace (weld in) one of the brackets for the back sway bar. Seam sealed the welds, then bought an off-the-shelf spary can of black rubberized undercoating to finish the job. After drying, I hit with with some white paint (the color of my car). Looks fine so far...will see as time goes on.
07-09-2008, 03:44 PM
#10
Burning Brakes
Yeah, I didn't like the fact that the Wurth stuff required a special gun either... however, it was supposed to be the thing to use in an attempt to recreate the proper spray pattern. The owner of car being done at the time wanted it so that's what he got.
The 3M stuff as well as the "off-the-shelf" spary can of black rubberized undercoating will both do the job. The latter tends to be a little heavier and you should hold the can a ways back...
Be sure to tape-up the lips of your fenders and anything else you don't want this goo to get on. Once it's dried you can paint over it. I tend to like use an enamel to do this with a combination of rag, sponge, or soft medium brush to not leave strokes dependant upon the area you're re-coloring.
Paul
The 3M stuff as well as the "off-the-shelf" spary can of black rubberized undercoating will both do the job. The latter tends to be a little heavier and you should hold the can a ways back...
Be sure to tape-up the lips of your fenders and anything else you don't want this goo to get on. Once it's dried you can paint over it. I tend to like use an enamel to do this with a combination of rag, sponge, or soft medium brush to not leave strokes dependant upon the area you're re-coloring.
Paul
