Hello everyone! I'm on the verge of buffing out my C4S. If the paint thickness is around 100 um, how much of it do I take off?

OR, does someone know how thick the clearcoat is and how thick the paint is on a 2004 C4S?

I.e. - I definitely don't want to be buffing out all the clear coat. That would really be NOT GOOD.

 

My thresh hold is 100 microns. What I mean is, I won't be aggressive below that. Could you have 15~30 micron left? Sure. Would that be enough to be aggressive? Most likely. Is it worth the risk? Absolutely not.

Why is it not worth the risk? Because there is no set figure you can work with. No one can say absolutely that every single Carrera has x-microns of primer, x-microns of base and x-microns of clear.

What I do know is that I have seen clear that had burned through at 92 microns(maybe more, but that was the reading I got). At 100 microns there's a really good chance someone will be left with plenty of clear that they need not worry. Once you break into the 90's, I feel like it's flirting with disaster.

At 100 microns, can you attack it with a very fine polish and not worry? IMO, yes. Fine polishes will not take off more than a micron if you're not careless.

I don't think the right question was asked. It should not be how much, but rather, when do I stop polishing? Properly polishing with a medium cut polish can get fantastic results without removing much clear(think 4~6 microns for the whole correction process on a hammered car). The results should be a reflection of how much you want to remove, and at that point it's more of a product of the process than a fixed number you're after. But you need a stopping point. For me, it's 100.

Porsche cars in good shape are usually floating around 120+. It's odd to hear you only have 100 microns. Do you know for a fact it needs compounding/buffing to get the results you're after? Have you consulted a local pro? It may not require such aggressive correction to get fantastic results.

I hope this helps.

 

I have seen several Porsches brand new reading 100 microns or less in some areas. I have also wetsanded a scratch down to 75 or so and had no problems. Best of luck.

John

 

Removing more that 0.5 mil (12µ) of clear coat will cause premature paint film failure as the ultra violet (UV) protection percolates to the top of the clear coat, there is ultra violet (UV) protection all the way through the paint, but the majority of it migrates to the top of the clear coat along with the thinner solvents and particles.

Therefore removing clear coat ultra violet protection is not a linear process; by removing a small percentage of the clear coat paint tends to remove a larger percentage of UV inhibitors. So once you remove too much clear coat you'll have no paint UV protection other than what you apply with a LSP

Paint renovation detailers can restore the finish on a car with paint correcting polishes; however there are some defects that are too deep to be repaired. There comes a point when you must judge wither removing a scratch will compromise the clear coat (0.5 Mil >) and if so you’ll have to ‘live’ with the imperfection (these can be aesthetically masked by using a Glaze)


A clear coat thickness is approx 2-3 Mils (50 - 75 µ) a paint thickness reading of 4 Mil < ( 100 µ (Microns) is reasonably safe for polishing. 3 – 3.5 Mil ( 80-90 µ) I wouldn't use anything stronger than > 2000 grit polish, 2.75 – 3.0 Mil (70-80µ) > 2500 grit polish and under 2.75 Mil (70 µ) use a glaze. If you have reservations about the amount of paint surface removed or the amount of paint coating remaining the use of a paint thickness gauge (PTG) is arbitrary


Note: 1 µ (micron) is 1/1000th of a millimetre or 0.0393700787 Mil or 0.001of an inch
· 200µ 8 mil + can be expected on older cars that have been hand painted or a re-painted vehicle
· 100 – 200µ 4 – 8 mil - normal paint thickness
· 80 – 100 µ - 3 – 4 mils, thin paint
· 80 µ < - less than 3 mil, very thin paint


These numbers are offered as a guide only, as there are too many variables to provide any more than an approximation.

[EDIT 10.17.10. Print size]

 

How did you get the 100 micron reading? Will you be using a gauge throughout the polishing? What imperfections are you trying to remove? What polisher, pads, and polishes will you be using? There are many variables here that will effect the outcome of the project. 100 microns isn't unheard of on a pcar and i've seen them as low as the 60s-70s. Anything under 70 or so, I wouldn't feel comfortable polishing. If using a da polisher and medium polish and pad, you'll be able to remedy most imperfections and the key from that point on is proper care and maintenance so the car won't have to be machine polished again or a mild polishing is all it would ever need. Hope this helps.

 

TOGWT - that was awesome info... THANK YOU!

Yes, I have a paint meter. Interestingly, in my Boxster S the paint thickness was around 120-150 um all over the car. The hood was in the 100-110 um range. I know that car hasn't been buffed since I was the one that "unwrapped" the white paint protector off of the car (I wanted to unwrap it like I was unwrapping a Christmas or birthday gift - yes, I'm a very old, "but kid at heart" person). So anyway, I find it odd that the hood would have the thinnest paint fresh out of the factory.

I bought the C4S used and it seems like the previous owner put it through a car wash. I am finally getting to buffing it out after owning it for a while. The paint ranged from 90 um to 140 all over the car. I highly doubt it's been buffed before.

Just fyi, I'm using a Porter Cable 7424 dual action orbital, orange pad (I have all pads), Meguiars 105 Ultra Cut. I'm also using Griot's 3 inch orbital for smaller spots - love that thing. I've previously used Griot's 1 and 2 polish, but it would take FOREVER to get anything done.

 

Just a suggestion: get some Meguiars 205 to finish off after you've used the 105 for some additional refining and more clarity. I use the Griot's new 6" orbital as well as that indispensible 3" unit. Great combo.

 

+1...definitely finish up with 205 and a softer pad.

 

I’m not trying to detract from the KBM method that utilizes M105 / 205 in the right circumstances it is an extremely efficient system. My reservations are that using a polish with an abrasive rating of 12/10 is not a panacea for paint correction.

I was taught to select a test area and use a pad / polish combination that would remove the scratches using the least abrasive polish / pad combination and apply it to the rest of the vehicle.

Relying on a ‘one size fits all’ approach to paint correction is just not my style

 

+1...the OP had Meg 105 so we made sure he knew to finish up with 205. With that said, the only polishing system we've come across to date that satisfies most issues, 90+%, almost every time on every make and manufacturer is the Menzerna Super Intensive/Super Finish combo. Hence why it's the only polishes for machines that we carry.

This combo from Menzerna is great because using just those two polishes, all you have to do is vary the pads you have and you can tackle anything from light-medium wetsanding to removing minor imperfections form washing. Truly a must for any detailer...pro or DIY.

 

Some help... KBM?

 

You just opened a can of worms my friend....

 

The KBM is the Kevin Brown method of paint correction using a PC, or even a rotary.

You will need to search out that process, it works very well on many paints.

Cheers,
GREG

 

KBM Method - http://www.detailingworld.co.uk/forum/showthread.php?t=136884

[I do not want newbies to try this method before using what is normally recommended!! NEWBIES- this is NOT for you!!!] Kevin Brown

 

Has anyone found that the paint thickness varied depending on the outside temperature? I.e. - seems like the paint measures to be THICKER when cold and THINNER when warmer?

TOGWT, when you say you use a "glaze". What exactly does this do? For example, I have a "3M Imperial Glaze". I applied it using the Griot's 3" orbital with a red foam. But it takes FOREVER to remove even with a microfiber cloth. In fact, I find that it's easier to remove with my fingers (with the brown residue getting onto my fingers).

I assume that the glaze is just a "filler" and that I would still apply my sealant on top of it?