How much clear does polishing actually remove?

B

benpocock

New member
I've tried a search but couldn't find a great deal...



I know it all depends on paint hardness etc but on average, how much clear would be removed if I went at it with #83/SSR2.5 with a light cut pad? It's for use on another forum where I'm getting told that machine polishing is bad and that you shouldn't use abrasive polishes. I'm trying to put the point across that polishing reduces a tiny amount of clear compared to what is actually there.



Thanks,



Ben.
 
Given all the "well, it depends" stuff that you're already aware of, IMO products like those are safe for once/twice a year polishing. That's assuming you're gonna keep the vehicle for long enough for it to matter anyhow. You can see how deep the marring is, so just use common sense about how much clear you take off. I'd rather either a) obsess about my wash technique and not mar it in the first place or b) leave much of the marring go. But then I'm of the "better imperfect original paint than a repaint" school of thought.



Before I got my wash technique scienced out, I used mild polishes on b/c paint over and over for many years with no problems. But I knew when to say "good enough" too ;) and IMO that's very important.
 
Yes you can't use #83 with a rotary monthly, but by PC there should be no problem using it twice a year. However there are too many people who jumps straight to #83 rather than trying to use something milder like #80 first. As said above it all depends.
 
I had my hood repainted. Afterwards, I noticed that it was covered with swirl marks. However, the bodyshop claims that they can remove the marks by running the car through "the machine and the pad". I asked if this removes any clear coat and the answer was no. Is this true?
 
drednik said:
I had my hood repainted. Afterwards, I noticed that it was covered with swirl marks. However, the bodyshop claims that they can remove the marks by running the car through "the machine and the pad". I asked if this removes any clear coat and the answer was no. Is this true?
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Sounds like BS to me. IMO a dry pad would introduce more swrils. The only way to remove swrils is that you have to remove a minor amount of clear. It can be done with a finishing glaze and a machine with very little clear removed.
 
jetskie said:
Sounds like BS to me.. The only way to remove swrils is that you have to remove a minor amount of clear....
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Yeah, the only way to remove below-surface defects is to lower the surface down to the bottom of the defects. You simply *must* remove paint to truly remove marring. It's the same principle as removing a scratch in a piece of wood; you have to sand away wood until you don't see the scratch any more.
 
This doesn't help much since its anecdotal, but I used an 1986 Canavan as a "test" subject awhile back when I got my PC. I polsihed the hood on that thing, a 2x2 area, a couple times a day with SSR3 for 14 days solid with a cutting pad and it's still got clear on it. I was experimenting with wet sanding, srapes, paint transfers, etc.. Just sayin' I think you would really have to polish the crap out of a car before you wore down the clear.
 
drednik said:
However, the bodyshop claims that they can remove the marks by running the car through "the machine and the pad". I asked if this removes any clear coat and the answer was no. Is this true?
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Hmmmm. This sounds exactly like what my body shop told me also. They told me that the clear doesn't get removed, but rather gets moved around alittle to remove the defect, and then melts/sets back into place.
 
Picus said:
This doesn't help much since its anecdotal, but I used an 1986 Canavan as a "test" subject awhile back when I got my PC. I polsihed the hood on that thing, a 2x2 area, a couple times a day with SSR3 for 14 days solid with a cutting pad and it's still got clear on it. I was experimenting with wet sanding, srapes, paint transfers, etc.. Just sayin' I think you would really have to polish the crap out of a car before you wore down the clear.
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Isn't it that if you've gone through more than .3-.5mils of the original paint, then clearcoat failure will result? You may still have clear but it'll all get destroyed within months.



The only way to know for sure is to use a thickness gauge, right?
 
III said:
Hmmmm. This sounds exactly like what my body shop told me also. They told me that the clear doesn't get removed, but rather gets moved around alittle to remove the defect, and then melts/sets back into place.
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Yup! That is EXACTLY what my bodyshop told me. Almost word for word. Hmm... I wonder now what I should do.
 
drednik said:
Yup! That is EXACTLY what my bodyshop told me. Almost word for word. Hmm... I wonder now what I should do.
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I think it depends on what products and techniques are used. I find it hard to believe that if someone is doing some major polishing with a rotary and an aggressive compound that no clear will be removed. At least a tiny bit would be taking off in my opinion.



Maybe the body shop is using a product and a technique that isn't that aggressive, thus doesn't remove anything like they said.
 
well I guess clear could "reflow" if it hasn't fully cured-we'd need a paint rep to really answer that. but I've been told that some "solids" such as glass are really liquids with near infinity viscosity-maybe clear coat is similar
 
sets back into place.




That explanation is absurd.



A swirl is scratch. And you remove the paint from around the scratch to 'correct' the defect.



Ask them if they have an Electonic Thickness Guage (ETG). If they can measure the film before they buff, and after, then it is a 'real' shop. If not, then they're 'dancing in the dark' with YOUR paint.



The real 'important' pat of your clear is in the topmost portion - that's where the real shine, and UV protection exists. If they remove more than .3 mil of that protection, you'll experience premature CC failure. Maybe not for 6-18 months, but will happen!



Methinks you are at the wrong shop...



Jim
 
Jimmy Buffit, I tend to agree with you, but it still makes me wonder you know? I mean I don't claim to know everything, and one would think a body shop would know all, or at least know more than myself in this area.



It's interesting because I've heard this comment made from "so called" professional detailer's in my local area. Years ago when I didn't do things myself, I took my truck to a detailer and asked exactly how much clear would be taking off after he was done with it. He told me none, and gave pretty much the same answer as the body shop's.
 
Guys....come on now. Wanna--the theory that glass is an amorphous solid--the one they taught us in Jr. High science...has been disproven. The clear on your car isn't "moving around" or "reflowing", not unless it was sprayed about a minute ago.



If you remove more then the .3-.5 mils, your paint may be subject to "premature" failure, which isn't going to be a few months...if the life of the paintjob is 10 years, premature failure may be 9 years, or 8, and of course, it depends on how much wax you keep on it, etc. I've got 15 yo paint on my roof and trunk, and I polished the crap out of it last year, I borrowed an eddy current tester (paint thickness) afterwards and I have some spots that total film thickness is only 3 mils, which means to me that a LOT more than .5 mil of the original clear is gone. The car has been sitting outside for the last 10 months, and the paint hasn't "failed" yet. EDIT: While I was typing this, Jimmy chimed in with the 6-18 months...so I guess the jury is still out on my car.



All that being said, what we consider "agressive" polishing, say #83 with a polishing pad on a PC, is not really very agressive on fully cured paint. A rotary with a wool pad and a leveling compound like they might use at the body shop will take off a LOT of paint in comparison.



III, no disrespect, but just because someone owns a body shop or works in one, doesn't guarantee they know anything about what they are doing. There are plenty of inept lawyers, doctors, and every other occupation out there--that's the real world.
 
Setec Astronomy said:
III, no disrespect, but just because someone owns a body shop or works in one, doesn't guarantee they know anything about what they are doing. There are plenty of inept lawyers, doctors, and every other occupation out there--that's the real world.
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No disrespect taken, and I agree with your statement above. That's why I said "one would think they would know all".
 
I used to do paint at a custom shop , clear is always removed when compounded .

If they say " none " either he has not a clue , or he's effectively saying he has no clue .

Unless none means not enough to ever matter in life , but still clear is removed ..



Clear will in no way reflow or what not because of heat . If it does soften up it will turn gummy and automatically lift or look like a " tear " in the clear .

Anytime you polish swirls out clear is removed , but if the buffer/detailer is paying close attention and not just running over teh paint , then it is only removed enough to level the swirls and that is okay .

Edges and such the clear can be much thinner though so compounding those areas is a no no unless you were the one who did the painting and know it's limits
 
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