Paint and Coatings Heat Resistance Testing

A quartz tube furnace/electrical resistance apparatus, developed by a team headed by Ed Skocik at Touchstone Research Laboratory, is used to perform high temperature paint stability tests. The test is designed to heat a painted steel sample to a predetermined temperature in a controlled atmosphere. The paint coating is then checked for degradation with adhesive tape or light abrasion.

A painted steel sample is connected into an electrical circuit with a low voltage transformer and a temperature controller. The metal temperature is measured by a thermocouple wire welded to the sample and connected to a digital temperature controller. The sample strip is enclosed in a 1-3/4 inch diameter Pyrex glass tube which is purged with nitrogen gas prior to and during the test to prevent oxidation. The time to temperature is approximately in the range of 30 to 60 seconds. When the desired temperature is reached, it is held for 60 seconds. The current is shut off and the sample allowed to cool in the tube furnace in the nitrogen atmosphere. The sample is then checked for paint degradation by taping and/or light abrasion with a hard rubber eraser or fine abrasive paper for paint removal.

This is considered a pass-fail test for screening purposes only. Typical failures are characterized by powdering and pick-off of the paint films.