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12+ Year Old Sanding Scratches on my Roof and Hatch
My 1987 928 S4 that was repainted Guards Red and clear coated at least 12 years ago by the previous owner. Since purchasing the car in 2001, I have been fighting trying to bring the depth back into the paint on the roof. There is a section of clearcoat failure that can be masked with M07 Show Car Glaze. While this is not really a worry for me as I religiously maintain the roof with the glaze after every wash and wax, I am concerned about what look like sanding scratches still.
I picked up a DA G110v2 some years back and I have Meguiars M105 and M205 for correction, but have not achieved any successful results really. I feel like the yellow foam polishing pad may not be abrasive enough to really get the scratches out. M105 is known to take out 1200 grit scratches, but these look deeper, more like 800-1000
From what I can tell you:
1) The marks seen in the picture appear to be deep sanding marks. It looks like an amateur may have color sanded the paint job sometime prior to my ownership.
2) above the driver side door, the clearcoat has failed in a spot about 1.5"x3". Layers of M07, M21 and Gold Class wax make it nearly impossible to tell the clear has failed there.
I would really like to take care of the sanding scratches. I tried taking photos of it again but it's just no hope to get the camera to show it (cheap digital camera). I can tell you that if I were to wash the car off, the areas where the scratches are would look rosy in the sun and not a deep red like they should. This is ONLY the areas that have the scratches.
I have wetsanded before, but only small spots where I have applied touch up paint to great success on my other cars. I don't trust myself wetsanding the roof of my car.
Also, what would be the best way to strip all the layers of wax off that have accumulated over the years when the time comes to correct it? Dawn Soap?? Denatured Alcohol??
I also talked to a friend who has had success using 3M Super Duty Rubbing Compound. I stopped by NAPA down the road to take a look at the stuff. It apparently removes sanding scratches of up to 1000 grit and finer. This worries me as It sounds like it can be quite nasty stuff and I don't think the 3M products are DA friendly. I would hate to drop more money into the Microfiber DA system if I can achieve success with M105 and a burgundy cutting pad.
I really need some feedback here and some recommendations. Thanks!
First and foremost I feel your pain. Now let me ask you this, you say your car has clear coat? Os is it SS (single stage) I don't see how #7 Glaze would help penetrate on clear unless it was single stage. By the look of the picture I would be very careful on what you try to do. Best bet is finding a professional detailer that takes measurements to see how much clear or paint left you have. That's is probably the safest way. Compounding too much is actually worse than color sanding or wet sanding.
When you polish the car, does the pad turn red? If it does, the it's either laquer paint or single stage.
Let me know where you are locatedthen I would be more than happy to find you a pro detailer that knows his stuff.
I do this for a living so I know the 1% of good detailers out there.
Dawn soap or probably the sasfest way to strip the paint (different ratios) Chemical Guy's Citrus wash and gloss.
Like I said I would be very careful, I would get a quote from a respectable detailer and let him takes the necessary measurements of your paint. Any corrections, this is a critical step.
Mongo, it's really difficult to determine exactly what this phenomenon is by looking at a photograph, but what you're seeing might look like sanding scratches, but they're actually the signs of 'sinkage' due to years of oxidisation caused by the sun's UVs. In layman's terms, the molecular compound of the paint begins to dry, shrink and sink over time (mostly in the center sections of the hood and roof.) Within a year or two the paint will begin to deteriorate until it begins to turn pink and chalky. This is very common on 911s and 944s that are pre '90s OE single stage Guards Red, but will also appear in some aged clear-coats as well. Francisco is correct when he advises determining whether the panel is single stage or base-clear. Base-clear will be a 'little' easier to work with in this situation but if this is single stage, you'll be working on a very thin and weak coat of red paint that is about as thick as a piece of paper ...and I've seen more than my share of 'burn throughs' on customer's P-cars due to over-polishing vintage single stage paint. Wish I was closer to ya to help ...good luck pal.
Mongo, it's really difficult to determine exactly what this phenomenon is by looking at a photograph, but what you're seeing might look like sanding scratches, but they're actually the signs of 'sinkage' due to years of oxidisation caused by the sun's UVs. In layman's terms, the molecular compound of the paint begins to dry, shrink and sink over time (mostly in the center sections of the hood and roof.) Within a year or two the paint will begin to deteriorate until it begins to turn pink and chalky. This is very common on 911s and 944s that are pre '90s OE single stage Guards Red, but will also appear in some aged clear-coats as well. Francisco is correct when he advises determining whether the panel is single stage or base-clear. Base-clear will be a 'little' easier to work with in this situation but if this is single stage, you'll be working on a very thin and weak coat of red paint that is about as thick as a piece of paper ...and I've seen more than my share of 'burn throughs' on customer's P-cars due to over-polishing vintage single stage paint. Wish I was closer to ya to help ...good luck pal.
+1.
I think it's base / clear. I'm pretty certain from the photo and description it was completely repainted that it's clear coat failure in one way, shape or form. Not trying to be Debbie downer, find the best detailed in your area and consult with them to be certain but I believe the assessment they are going to give you is that it needs re-sprayed.
You have the proper tools to correct it if it's just mild oxidation or sanding scratches. Sounds to be more serious.
It has been a while since I updated this thread. It is unfortunate that my paint failure on my roof and hatch is identified to be crazing paint. The front cowl trim also is showing signs of this. These sections of the car will need to be sanded down and primed with an epoxy primer and sealed prior to repaint to prevent the crazing from appearing again.
10-28-2014, 03:55 PM
12+ Year Old Sanding Scratches on my Roof and Hatch
