A dirth cheap PTG

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Martini

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(Yes, I've read this thread)

I was wondering if you have any experience with very cheap equipment.

My idea is to buy something that might be useful for detailing (having an idea of how much paint you remove) AND would be able to tell you if a body panel has been resprayed (thicker paint) when buying a used car.

I've seen these two on eBay:

Digital Automotive Coating Ultrasonic Paint Iron Thickness Gauge Meter Tool FG | eBay

Digital Paint Coating Thickness Gauge Meter Iron Aluminum Base User Friendly HG | eBay


At least one of them can be calibrated, which inspire some sort of confidence.


Have you used one?
 
I wrote that thread.

The problem is that the margin of error with these inexpensive ones is so great that your accuracy is more on the level of mils, not microns.

Unfortunately, photobucket no longer let's you do 3rd party hosting (otherwise you could see my tables), but even when calibrated, the scale of accuracy is too large to make these paint thickness gauges useful for automotive detailing.

If you compound the paint and the gauge says you have 5 mils of paint, the reading may not change until you have 4 mils of paint left. That's 25 microns, which would be a disaster as you know.

Unfortunately, the Nicety is about as low end as you should go when it comes to measuring paint thickness. You get what you pay for.

And remember, that's the thickness of the primer, base coat and clearcoat you're measuring. On top of that, even if you take away a certain amount of clearcoat, you're removing a protective layer. The PTG will give you a "starting point" as Mike Phillips would say.

(Sent via my mobile device...)
 
I personally think you don't need one.23 years detailing every kind of car from Ferrari Bently to jets never bought one.Common sense tells you to ease up on bodylines and high points.
 
craigdt said:
It's probably not as accurate as the more expensive versions, but it gives a good idea.
I'd rather have the cheap one, than not have one at all.
Click to expand...

They're definitely not as accurate, and they don't give you even a "good" idea. They're way off, so you start way off.

Just look at these tables of calibrations I did.

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Basically, what they are showing is that when you're paint is thinner (i.e., in the range of car paint thickness), the readings are way off. When the paint is thicker (i.e., maybe a respray or around 10 mils - - what car paint is that thick??) only then does it become reliable for these cheaper gauges.

(Sent via my mobile device...)
 
If a moderator could edit my first post and remove the h from dirth, I'd appreciate it.

craigdt said:
Here is my thread using a cheap PTG
https://www.autogeekonline.net/forum/auto-detailing-101/98447-report-pics-showing-how-much-clearcoat-removed-during-machine-polishing.html
Click to expand...
I don't think it's *that* cheap.

Did you test it with plastic feeler gauges or something in that spirit?




Thanks for the feedback guys!
I'm still undecided. I think I can draw a parallel with a vernier caliper. A good one is $150, mine is $10. And while the good one is gonna give you a more reliable result without any second thought. The cheap chinese one will be about just as reliable...provided you zero it before every measurement to be safe. If a cheap PTG gives decent results when you're cautious (and calibrate it before every use), then it's a tool for me. The question is not $15 vs $200 but $15 vs nothing.
 
IDK much about paint gauges but I say save up until you can afford a good 1 that's actually reliable.
 
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