oldmodman
05-04-2008, 02:21 PM
Cliff notes.
It's worth the money and works great for way less money.
I ordered it online since it was not carried in my local Harbor Freight store. It arrived in about a week.
It looks like a generic remote reading temp gauge, with different setting buttons.
It has a trigger for on-off and take a reading.
On the side it has a backlight button, cal (or calibrate) button. Up and down buttons for changing the calibration. And a button to toggle between inch and metric. The inch readings are in thousands of an inch and tenths of a thousandth. The metric is in microns and if much more useful since it reads in thousandths of a millimeter, a much smaller measurement.
Before using the gauge you must calibrate it. You take a reading of a round metal disc that is provided with the gauge, then zero the gauge with the up and down buttons. Then you take another reading of the metal plate but with the test strip between the gauge and the plate. And you use the up and down buttons to make the meter read exactly what is printed on the test strip. Then you are ready to use the gauge.
The first car I tested it on was my 1992 Ford Explorer. I got reading of 112 microns on the hood, 83 on the roof, and 221 on the new paint on the repaired drivers door. I know that the door was re-skinned so I know that it has only new paint on it. Just goes to show you how thin the paint build is on factory paint. I tested several other cars with similar results.
Now for the interesting part.
I got out my test hood, sandpaper, spray bottle of water, rubber sanding blocks, Makita rotary, heavy wool pad, and Meguiars #84 cutting compound and went to work.
I started by taking ten measurements at various places on the hood. I got readings that were very consistent. 127 down to 114 microns.
After sanding for appx one hundred strokes, back and forth with 1500 grit paper and water. the readings were 123 down to 109. All the shiny texture was gone and the hood was ready for the 2500 grit to remove the "heavy" scratching from the 1500.
Same process with the 2500 except it took around two hundred strokes before I was satisfied. The post sanding measurements were 119 down to 107.
The I hit it with the wool pad and compound, only another micron was removed. Then just for the fun of it I used a finishing foam pad and Menzerna Nano and NO change in thickness could be measured.
If all the published reports about clearcoat thickness have been accurate the with a total of 9 microns being removed (from this test hood). This amount of removal is consistent with published, allowable limits for clearcoat removal of 25% of average thickness. I would advise anyone read this tutorial on paint thickness
Automotive Paint Thickness Gages (http://www.mobileworks.com/paint-thickness-gauges.html)
before ANY sanding projects. As has been used in many legal disclaimers "YOUR RESULTS MAY VARY".
In conclusion, this cheapo gauge is absolutely worth the money. It could help prevent you from ruining your finish. As an example, I might be willing to attempt wet sanding my repainted door, a little less comfortable trying it on my hood, but absolutely NOT on my roof. Think of it this way. Would you rather suffer with a little bit of a scratch remaining after a modest sanding and polishing job, or would you prefer to have to pay for a repaint because you absolutely HAD to get every bit of that scratch out?
It's worth the money and works great for way less money.
I ordered it online since it was not carried in my local Harbor Freight store. It arrived in about a week.
It looks like a generic remote reading temp gauge, with different setting buttons.
It has a trigger for on-off and take a reading.
On the side it has a backlight button, cal (or calibrate) button. Up and down buttons for changing the calibration. And a button to toggle between inch and metric. The inch readings are in thousands of an inch and tenths of a thousandth. The metric is in microns and if much more useful since it reads in thousandths of a millimeter, a much smaller measurement.
Before using the gauge you must calibrate it. You take a reading of a round metal disc that is provided with the gauge, then zero the gauge with the up and down buttons. Then you take another reading of the metal plate but with the test strip between the gauge and the plate. And you use the up and down buttons to make the meter read exactly what is printed on the test strip. Then you are ready to use the gauge.
The first car I tested it on was my 1992 Ford Explorer. I got reading of 112 microns on the hood, 83 on the roof, and 221 on the new paint on the repaired drivers door. I know that the door was re-skinned so I know that it has only new paint on it. Just goes to show you how thin the paint build is on factory paint. I tested several other cars with similar results.
Now for the interesting part.
I got out my test hood, sandpaper, spray bottle of water, rubber sanding blocks, Makita rotary, heavy wool pad, and Meguiars #84 cutting compound and went to work.
I started by taking ten measurements at various places on the hood. I got readings that were very consistent. 127 down to 114 microns.
After sanding for appx one hundred strokes, back and forth with 1500 grit paper and water. the readings were 123 down to 109. All the shiny texture was gone and the hood was ready for the 2500 grit to remove the "heavy" scratching from the 1500.
Same process with the 2500 except it took around two hundred strokes before I was satisfied. The post sanding measurements were 119 down to 107.
The I hit it with the wool pad and compound, only another micron was removed. Then just for the fun of it I used a finishing foam pad and Menzerna Nano and NO change in thickness could be measured.
If all the published reports about clearcoat thickness have been accurate the with a total of 9 microns being removed (from this test hood). This amount of removal is consistent with published, allowable limits for clearcoat removal of 25% of average thickness. I would advise anyone read this tutorial on paint thickness
Automotive Paint Thickness Gages (http://www.mobileworks.com/paint-thickness-gauges.html)
before ANY sanding projects. As has been used in many legal disclaimers "YOUR RESULTS MAY VARY".
In conclusion, this cheapo gauge is absolutely worth the money. It could help prevent you from ruining your finish. As an example, I might be willing to attempt wet sanding my repainted door, a little less comfortable trying it on my hood, but absolutely NOT on my roof. Think of it this way. Would you rather suffer with a little bit of a scratch remaining after a modest sanding and polishing job, or would you prefer to have to pay for a repaint because you absolutely HAD to get every bit of that scratch out?