Why sand off oxidation?

[imported_WhyteWizard]

The reason is this: Typically, oxidation forms a layer and protects the paint underneath. Every cutter or polish has emulsifiers, carriers, cleaners or other oily liquids. When these liquids hit the oxidation and wet it, they make the oxidation look like good paint. So, it's hard to tell when you've cut through to honestly good paint. Not absolutely impossible, but hard, and usually it requires you cut deep enough for certainty, which mean a little extra.



Plain water on the other hand, while it still makes the oxidation shine, doesn't make it look as good, the color is usually somewhat washed out - pun intended - and lighter. By wetsanding with something like Trizact 3000 you can see when you've cut through the oxide. What you should be going for is a stripped look, darker, good paint just breaking through the oxidized lighter paint. Think Zebra stripes. Good lighting is critical and lets you see what I'm talking about, but you can dry as you go and because the water will dry out of the oxide you'll be able to see when you've cut through. It'll just take longer, but you'll have really good control.



Remember, the point is to just break through the oxidation and stop.



Then you can easily buff out the 3000 grit and remove the remaining oxidation using the KB method or with Hi-Lustre Finish-it, with a rotary followed by the Makita BO6040 like I was demonstrating at SEMA this year, or with whatever you're used to.



I think wetsanding off oxidation in some, but not all cases, is something worth considering.



Robert

 

[salpac]

makes sense to me... good info.

 

[RaskyR1]

Sounds like it would remove a lot more paint IMO.

 

[dschia]

This is very good info, unfortunately some oem paintwork is getting absurdly thin..

 

[SoCalB6]

Remember, the point is to just break through the oxidation and stop.



I think wetsanding off oxidation in some, but not all cases, is something worth considering.

+1. Well put!:xyxthumbs

 

[imported_WhyteWizard]

When I wrote this post I was thinking primarily of single stage reds that have gone pink and dark blues that have gone powder blue. That's why I mentioned the color difference, that's something you wouldn't get with clear coat, but I neglected to write it.



In my thirty years of detailing I've used this method about half a dozen times is all. The first time was after doing a red Porsche 928 that had been left where sprinklers had soaked it every day for a couple of months with no one drying the car. The combination of water spot and wash out of the pigment made for a real mess. I buffed the car out the first time only to have it die back after a couple of washes because the "natural oils" from the product I was using at the time made the paint look good before I got down to the undamaged paint.



When I came back to re-do the car, I broke out the sand paper and using the technique I described ended the conversation. That was before Trizact so the finest paper I had at the time was 1500 but paint was more forgiving back then. Trizact makes the process much safer and easier.



Like I said, this is something I've done maybe half a dozen times in thirty years, but it's been absolutely the right move when I did. The alternative was having the car painted so the risk was justified.



Thanks guys.



Robert

 

[RaskyR1]

In a case where there is adequate material I think this would definitely yield better end results, but because of the amount of material that is removed, I think it would have to be done on a case by case basis. :xyxthumbs

 

[Dan]

I disagree. I find a good chemical paint cleaner (non abrasive) to be much more time effective as well as saving more paint. I like to remove all the oxidation first, then think about what course of action to take. The chemical cleaner will strip the oxidation and leave the paint alone, in many cases only requiring a medium-light level polish. This is very important to me as at that stage, the paint is probably very thin. As always, using a PTG to determine what steps to take next.

 

[BobD]

I disagree. I find a good chemical paint cleaner (non abrasive) to be much more time effective as well as saving more paint. I like to remove all the oxidation first, then think about what course of action to take. The chemical cleaner will strip the oxidation and leave the paint alone, in many cases only requiring a medium-light level polish. This is very important to me as at that stage, the paint is probably very thin. As always, using a PTG to determine what steps to take next.

I agree, this is what I used one my old red Honda Civic.

 

[Mike_Phillips]

I've had the good fortune to work on a lot of oxidized single stage paints in my life and can't think of a single situation where I would sand over use a quality paint cleaner.



Usually anything with single stage paint is old and that already presents a number of potential problems not the least of which is,



How many people have worked on this car before you and what did they use?





Single stage pains are softer and if they're old they can be dried out. Everything you could accomplish with the right chemical would be a safer approach than sanding on the paint.



Besides the above, sanding oxidized paint is just going to load up your papers very quickly with dead paint. Nope, doesn't make sense to me and I'm a proponent of sanding when it's right for the car.



These are some of the best before and after pictures I've ever taken after removing oxidation and restoring a show room new finish. There are raised body lines and high points on the car that a person could have easily sanded through and exposed primer.



Photos courtesy of MeguiarsOnline.com



Before

After

I think I'll stick to the tried and true methods that worked on that car up there and this car below...



Before

After

By all means if anyone reading this wants to remove oxidation by wet-sanding then if it's your car go for it!

 

[David Fermani]

Anyone ever use a yellow brick bug sponge(wet) and compound to remove oxidation as a pre-polishing step?

 

[Mike_Phillips]

Anyone ever use a yellow brick bug sponge(wet) and compound to remove oxidation as a pre-polishing step?

No.



I have used Comet with a terry cloth wash rag to wash it off using the abrading power of the Comet and the nap of the terry cloth with great success. I've never used this approach on cars where saving the original paint was vitally important but I've used it on lesser cars.

 

[Mike_Phillips]

This was a down and dirty job done with M105 with a rotary buffer and a wool pad, followed by M80 Speed Glaze with a PC





Before

Side-by-side

After

 

[Greg Gellas]

Wool pad with SIP worked fine for me Of course followed up with 203 dow to 106

 

[Dan]

Anyone ever use a yellow brick bug sponge(wet) and compound to remove oxidation as a pre-polishing step?

No but Turtle Wax ICE Liquid clay works pretty well to knock off oxidation in the wash step. Its useless as a clay, but as a paint cleaner and wash in one its great. I get great results using that stuff then follow with something like #66 as a quick two step that can be done in about an hour.

 

[Dan]

Wool pad with SIP worked fine for me Of course followed up with 203 dow to 106

No doubt that works, in fact it looks great, but the chemical cleaner will be faster and not clog/trash up your pads as much and possibly take off less paint.

 

[imported_WhyteWizard]

The Porsche I did looked very much like the red Mercedes before and after and I was using Meguiars products at the time. A couple of months later it had died back to pink. After sanding through the oxide down to good paint the car looked right and didn't die back.



I'm sure you guys are just much more skilled than I am and I'm not trying to start a food fight over something I've done only a few times in thirty years. Still, have you seen that Mercedes lately?





Robert