Mabuhay

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.

chopperzz

I'm not a pro in this business, but i am perplexed by your question. Is it possible to know the thickness of clear?
What is the chance that all areas have the exact thinkness of clear?
If you buff with a machine, to a specific thickness, how do you manage the depth of the machine, to be the same everywhere?

Marine Blue

Has the car been buffed out in the past?

The amount to buff out really depends on the condition of the paint. If it has light swirls you really only need a mild polish to perform the right amount of correction. If you have deeper swirls and scratches you'll need a more aggressive polish to level the paint. Some times it doesn't make sense to chase really deep scratches as it will remove too much paint and you're better off leaving it alone.

Posting some close up pictures would certainly help to determine what type of corrective polishing is required.

Also what type of equipment are you going to use to buff the paint, rotary or dual action?

Cosmin

do this:
measure the inside of the door , and compare with what you got initially , that will tell you how much clear you deal with , remember the car has thin spots too , and readings are just an info of the car paint history , is not really accurate.
everything between 100-200 is normal , everything under 100 is thin , i will not compound , aggressive that area. a polish should be fine , with polish pad.
also keep in mind to put extra coats of protection.
hope this helps , Cosmin

Mabuhay

The only way for us to know how much clear coat is on the car is from Porsche. I read somewhere that it was documented, but I couldn't find it when I searched. I was hoping the someone would readily know where this would be.

I have a paint thickness meter for me to monitor how much I take off. I take multiple readings in many spots on each panel.

I'm pretty familiar with the info above. I just need to know how much to take off at this point. I'm using Meguiar's 105 Ultra Cut Compound using Griot's 3 inch dual action orbital with orange foam pad for small areas. For larger areas, I use a Porter Cable 7424 with an orange pad as well. For really hard paint, I use the yellow pad.

Prior to discovering the M105, I used Griot's Polish 1 and 2. But these things took FOREVER to get any decent results. The Porsche paint is much softer when compared to Audi (has been the hardest so far, where even the M105 takes a while to work).

I don't know if the car has been buffed before. But I register 90 um to 120 um through out the car.

Marine Blue

You should be safe with the combination you are describing. That is exactly what I use as well although I follow up with M205 and a fine polishing pad at speed setting 5 on a 7424 XP.

See Cosmins reply quoted below for a good way to determine how much paint remains. If you still have any of the factory orange peel the car probably hasn't had much of the original paint removed.

Mabuhay

That's a darn good idea.. running out to the garage now...

The door measurements varied all over the place. But most seemed to be 70 um to 100 um. But it looks like it's also clear coated.

The sunroof registered from 95 um to 105 um. I took it down 85-100 um. Looks great! But this is why I am now wondering how much clear is left...

TOGWT

Paint Thickness

Using a medium abrasive polish and a rotary polisher will remove approximately 0. 1 Mil (3µ ) Range 0.8 – 1.1 Mil (20 – 28 µ) from the paint surface (typically 4 passes at 1500-1800 RPM) but there are many variables such as the abrasive grade of the polish or compound and speed and pressure used that may affect the paint removed) These numbers should be checked with a paint thickness gauge (PTG) There comes a point when you must judge wither removing a scratch will compromise the clear coat and if so you’ll have to ‘live’ with the imperfection.

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 (70-80 µ) > 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

Notes:

1. 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. So once you remove too much clear coat you'll have no paint UV protection other than what you apply with a LSP [EDIT]

2. 1 µ (micron) is 1/1000th of a millimeter or 0.0393700787 Mil or 0.001 of 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.

Paint thickness will often depend upon the OEM paint specification, which can vary by vehicle assembly plant. It’s interesting to note that painters must now demonstrate proficiency with an electronic paint thickness gauge in order to become certified to perform paint refinish warranty work for General Motors Corp. (GM) vehicles.

[EDIT 11.04.10 Note # 1 added]

Auto Concierge

How much you remove will vary, but M/105 is very aggressive and it will remove the defects with the gear you say you have. Proceed slowly until you have a feel for what you are doing, the DA polisher is safer than rotary correction but with that machine you can still strike through when using M105.

Mabuhay

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?

Marine Blue

Glaze is an oily filler that hides swirls.

Best way to remove it is a two step process. Start with a fresh Microfiber and wipe down the entire car quickly, don't bother trying to remove everything, just remove the bulk of the glaze. Then get another new Microfiber and start over. You'll find that the second wipe down will be much easier and it will leave a deep swirl free finish.

A glaze will last about two to three weeks at best. You can try to prolong it with a coat of carnauba which helps seal the oils.

TOGWT

Temperature affect on Paint Thickness

A dark colour paint surface can be subjected to temperature swings of 60.OF +/- 10.OF. With an ambient temperature of 80.OF a dark colour horizontal surface subjected to infrared radiation (UV-A) can reach a temperature of 150.OF.

The urethane used for automobile paint is classified as a semi-solid, micro structured permeable membrane, due to its micro-fissures, or pores’, being a thermosetting polymer it remains flexible, whilst retaining its tensile strength, to enable it to expand and contract to follow temperature fluctuations (elongation and contraction). So be cognizant that paint thickness readings will vary in accordance with ambient temperature.

Measure paint thickness on a horizontal surface at temperatures below 50 degrees, and then measure the same spot at mid-day at temperatures above 80.OF. After an hour measure the same spot, you will then obtain a thicker paint surface reading. Conversely with colder ambient temperatures you will then obtain a thinner paint surface reading. There are many variables that will affect the paint readings, i, i.e. instrument accuracy, humidity, paint surface colour, reflectivity, and etc.

TOGWT

In a painter’s terminology, glaze is a term used to describe a process in which the full gloss of paint is restored. A detailer’s glaze is purely an aesthetic product that contains a very, very light abrasive (Kaolin) to lightly burnish the surface.

A glaze provides gloss but very little protection; it's often referred to as Show Glaze because glazes tend to create a "wet-look" (jetting) shine they have come to be used by enthusiasts to maximize shine and gloss on concourse show cars, historic and exotic vehicles.

There are two types of glazes; wax /oil based and polymer-based, an oil / wax based glaze can only be used under a carnauba wax, as a polymer sealant will not bond. They are formulated with micro-fine abrasives (Kaolin clay) that will burnish the paint (but will not remove surface imperfections) it’s comparative abrasion scale (CAS= 0.75/10) along with an emulsion of polymers or solvent oils as the carrier system, the Carnauba wax and Kaolin `fills in' small paint surface scratches, abrasions and swirl marks, without removing them.

There filling abilities usually dissipate in a matter of days before the surface abrasions become visible again, washing the paint film surface will accelerate this process, using a Carnauba wax as an LSP will help the durability of the glaze somewhat by ‘sealing it.