How many passes with #83 to get to the paint?

[NVcobra]

Hi, Im trying to get a point of reference about the PC and #83. Lets say we have a modern clear coat car with avg hardness,avg thichness and about room temp work area...how many passes would you say it would take working a 2x2 area to hit the color? Or at least to the point of removing to much clear resulting in soon clear failiar? Ive been working my hood abit,Id say at least 10 passes,its almost perfectly leveled. Just trying to see where I stand,thx

[Accumulator]

Most of us won`t want to go out on a limb answering a Q like this, just too many variables. But IMO what you`ve done is gonna be OK *in most cases* but I wouldn`t make a habit of it. I`ve worked some panels with comparable products for a lot more than 10 passes without any problems. But again, you can only do this so often. You`re smart to consider cc failure, which will happen with *far* less clear removal than it takes to hit color. Remove only a calculable percentage of the clear (which isn`t much) and you`d better start keeping it out of the sun...

[LightngSVT]

So then in essence wet sanding to acheive a level finish will also result in CC failure (depending on paint thinkness)?

[NVcobra]

Hey thx Accumulator, I think im actually "wetsanding" so to speak with the PC,time isnt a factor. Ive finally got a garage to keep it out of the elements and im just working on a panel or so a day which takes me a few hours. So assuming the car has had no prior buffing and all things I mentioned above, In you opinion and at my own risk do you think I can go ahead and level it? thx

[jr weeks]

Yes, once you remove about 3 10ths ( .3) of 1 mil of clear, you`re getting onto shaky ground with taking out the majority of the UV inhibitors, which reside there near the surface (chemical migration during cure). Most oem makers cite the .3 figure to work UP to, but not to go beyond when compounding and sanding.



Like Accumulator said, if you can keep the car out of the sun, you can do fine for a long time (some show cars get away with it this way, but most of those are aftermarket painted and had more clear applied too, in oreder to compensate) but if it`s a daily driver with oem paint that sees a good sun load, the resin system WILL break down once the UV is gone, albiet gradually and not immediately. The demise WILL occur though.



I painted one of my cars and blocked off all the orange peel, but I layed 4-5 coats of clear on it, because I knew I`d be wetsanding about 2 off. It`s been almost 8 years now, and the paint is still fine. It gets limited sun exposure . If that were oem paint, I know it would have failed by now.



Be careful.

[imported_agentf1]

Not sure, I lost count. I would think it would be REAL HARD to burn through cc with a pc and 83. Lets just say I have buffed the living @#$% out of my Z06 trunk and barely put a dent in it.

[NVcobra]

Thx...agentf,thing is,is that you really dont know if youve..
barely put a dent in it. unless you can measure it or wait and see in time if it fails. Sorta like walking on ice hard to tell how thick it is just by observing it from above. My paint is getting leveled but still has some water etching and pitting slightely,just wondering if i should live with it or go on and level it out. Thx

[imported_agentf1]

True, but believe me, it is real hard to go through clear coat with a pc and 83 as it is not really powerful enough and usually just rounds the edges of the scratches. I don`t think you need to worry about it nearly as much as you are. Some people say it is impossible. I am not sure I would go that far but it will definetly require ALOT of work. I have literally buffed for 2 hours trying to remove a fine scratch and barely touched it, then broke down and hit it lightly with 3000 and buffed up and the orange peel hardly shows any difference. PC`s are not very aggressive.

[NVcobra]

I agree its not that agressive compared to other procedures but knowing cc is only 2.5 mils thick(single piece of paper) and that we can only remove up to .5 mils safley(.3mil recomended). Makes me wonder where Im at very seriously,lol. Thx

[imported_agentf1]

Pick yourself up an old panel from someplace and try to buff it through. I will bet that you will give up before you do with a PC. Nothing wrong with erring on the SAFE side though. Now if you said a rotary. :shocked

[NVcobra]

Good idea, Ive thought of doing that to,but then the next question that comes to mind is how will I know how much difference there was between my clear coat and the spare panel? Was it as thick as mine? Was it as hard as mine or softer? Ohhh were will the madness end!!!:rolleyes:

[Accumulator]

FWIW, at last year`s Autopia g-t-g in St. Louis, a knowledgeable and well-respected Autopian cut through the clear on a 190 Benz using PC/#83/Meg`s cutting pad. So it *can* happen.



NVCobra- I dunno...I just hate the idea of people taking off a lot of clear unless the paint was sprayed with that in mind. Doing it to factory paint is a real gamble and doesn`t leave any wiggle-room for later. Better to have some imperfections than have to repaint the car IMO.

[joburnet]

You can tell how much paint your taking off by how many scratches you are getting off. I have worked on scratches that were clearly not through the clear coat for ridiculous amounts of time and not had a lot of progress with them meaning that I`m not taking off that much paint.



Honestly I would say try to get the results that you want and not worry much about the clear coat getting too thin because you will probably not be taking off very much paint. but that`s just my two cents.

[NVcobra]

Thx, good point,I still have what I call level 2 scratches..ones deeper that normal swirling but not deep enough to catch a fingernail...hmm question is are they deeper than the .5 mil ,lol thx

[Accumulator]

Heh heh, when you`ve seen clearcoat failure on an otherwise nice car, you tend to get pretty conservative about this stuff ;)



When you think in terms of fractions of mils, the "so deep you catch it with your nail" is sorta like saying "so deep you can trip over it" :D



But yeah, *generally speaking* you can PC with DACP quite a bit without it being a problem. Just be aware that it`s not literally foolproof. Most people *do* find that the PC is *not aggressive enough* for what they want to do (whether what they want to do is sensible is another matter).