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Bullitt AK
07-20-2010, 10:07 PM
how do i know if its safe to polish a vehicle? not knowing how much the vehicle had been polished in the past, repairs, etc. because eventually if polished too much you will affect the base coat even if its not complete strike through?

Mindflux
07-20-2010, 10:28 PM
You don't. You're flying blind (effectively).

Bullitt AK
07-20-2010, 10:29 PM
even with a PTG i still dont see how you could tell how much clear is left...if all your doing is assuming that a certain amount of clear remains

Mindflux
07-20-2010, 10:29 PM
even with a PTG i still dont see how you could tell how much clear is left...if all your doing is assuming that a certain amount of clear remains

Right, that's why there are more expensive PTG's that'll read layers. Im the MAN

Bullitt AK
07-20-2010, 10:33 PM
yes but obviously most people cant afford it and 99.99% of people who regularly polish autos arent going to have one thats 3k..so you just polish and hope there is enough clear left? because to my understanding the affects wont even be apparent until later unless its a complete strike through

Mindflux
07-20-2010, 10:34 PM
yes but obviously most people cant afford it and 99.99% of people who regularly polish autos arent going to have one thats 3k..so you just polish and hope there is enough clear left? because to my understanding the affects wont even be apparent until later unless its a complete strike through

Yeah, in the end you're running a numbers game. Chances are most cars aren't going to have problems with cutting through the clear but when you do that's what you have business insurance for.

Honestly I don't see too many people bring up actually having this problem. Either they don't have it often, or aren't admitting it.

Bullitt AK
07-20-2010, 10:54 PM
well im just using a PC instead of a rotary too..

detailjohn
07-20-2010, 11:21 PM
Right, that's why there are more expensive PTG's that'll read layers. Im the MAN

Paint thickness gauges that read layers only work on non metal bodied cars. Unfortunately one is not available yet for metal bodied cars that I know of.


John

feslope
07-20-2010, 11:31 PM
even with a PTG i still dont see how you could tell how much clear is left...if all your doing is assuming that a certain amount of clear remainsIn most cases the door jambs, inside the trunk or under the hood will have the thinnest clear coating on the vehicle. After many PTG measurements on several areas of the car you should get a pretty good idea of what you have to work with. Don't ever assume that a single panel is uniform. Measurements on my 2004 Prius hood run from 79-136 mils. Measurements on my 2010 fusion hood run from 197-212 mils. The Fusion is Pearlcoat, I would like to measure that coating thicness with one of those multi-layer gauges,

feslope
07-20-2010, 11:33 PM
Paint thickness gauges that read layers only work on non metal bodied cars. Unfortunately one is not available yet for metal bodied cars that I know of.


JohnInteresting, I did not know that.

Bullitt AK
07-20-2010, 11:34 PM
here is something from another forum as an approximation...is it a good guideline to use?

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)

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.

Mindflux
07-20-2010, 11:37 PM
200 mils would be insanely thick! Cutting through .5 mils of clear is usually considered risky and can lead to clear failure. Are you sure you are reading that PTG right?

Bullitt AK
07-20-2010, 11:38 PM
lol pretty sure he means microns not mils..and im pretty sure they have ones that can read multi layer on composites so maybe for corvettes, viper gts or other high ends that arent metal....
and judging by the approximation that i posted how can you tell what grit a polish is?

Mindflux
07-20-2010, 11:40 PM
lol pretty sure he means microns not mils

I hope so.