I have heard there is a "tape" availbalde to attach on a metal surface to measure max temperature on that surface. The "tape" will be colored according to the max remperature expreienced. Anyone who knows where to get this "tape"?
Try TIPtemp.com or call Neil Humphries @ 609-239-1900.
They do all kinds of those tape type temperature measuring devices.
BTW, what temperature range are you looking for, and how accurate does it need to be?