Help on HF Thickness gauge

[Heatgain]

I need some help on calibrating this Harbor Freight thickness gauge. I'm not sure if I'm doing it right or if the gauge is defective.
1) Which is the "bare" portion of the Calibration Plate.. the blue side or the white side?
2) When calibrating off the Test Foil atop the Calibration Plate, (2nd calibration), one just merely places the Test Foil adhered to its plastic backing on top of the Calibration plate? Or should the Test Foil be peeled off its plastic backing and adhered directly to the Calibration Plate?
3) After calibrating, when one exits the calibration mode by pressing the calibration button, (step 9 Calibrating the Gauge), is the Gauge supposed to turn off or stay on? Mine shuts down when I exit the calibration mode by pressing the calibrating button, and has to be turned on again by depressing the trigger.

Thanks.

[Pats300zx]

I had some trouble figuring this out as well. You want to make sure that you pull off the thin plastic coating on the bare metal piece. I couldn't figure out why my gauge was off by .5mils until I figured out that the bare metal piece had a film on it that had to be removed.

You place the calibration foil on top of the plate after getting a "O" reading on the plate itself. Be sure to measure the area with the writing on it. I believe its 3.8 mils.

After exiting the calibration mode mine shuts down as well.

I just used mine on my last detail and it worked flawlessly. You can't beat it for the money.

[Heatgain]

Thanks. I'll try it again tonight.
I called HF "technical assistance" to ask these questions, and the "technician" told me to use the white side of the calibration disc. Never mentioned to peel the white off the disc. Love call center "techs."
Another question. If the unit shuts off after getting out of the calibration mode, and you have to turn it on again to use it, doesn't it lose the calibration you just did??

[karburn]

I just bought one of these, and I've already had problems with the thing not staying calibrated. The instructions are pretty clear: bare metal side of the disc-peel pack the plastic, etc. HOWEVER, after doing the calibration, I let the unit shut off and then restarted it and tried a reading on the test strip again. (I was using um - microns - and the reading would flash 99 for an instant, then jump to 154-155. I just don't know if I can trust the thing, as I've been getting readings on an '06 Mini Cooper of 65-68 microns on the hood, and 95 on the roof. Seems a might THIN. I tried it on my old 87 Benz and got readings of around 150 on the doors, 95+ on the deck lid and maxed out the unit at 1000+ on the hood. Guess which part had been resprayed.

Any insights on the reliability of this unit or links to other threads about this unit are appreciated!!!

PS: Just as a precaution, I replaced the battery and recalibrated again. Same results.