by Ron Joseph
December, 2005
Curing Automotive Coatings Using Heat
Q. I am trying to decide if I should put in a Junair QAD system in my
current spray booth that will speed up the paint finish process. I am presently
doing 5 cars per day in my booth now and am being told I can do an extra 1-2
cars per day by reducing my flash off time (up to 70%) and bake time (up to
45%). What are your thoughts on this?
A. I do not know the Junair QAD System, therefore let me give you a generic
answer. Heating of paint can be advantageous to speed up the drying and curing
of coatings, but you must insure that you don't overheat the coating and more
importantly, you must first flash off all or most of the solvents. If the high
temperature hits the painted car too quickly you might form a skin of cured
paint that prevents entrapped solvents from getting out. If that happens you
will have serious paint blistering or worse, peeling.
Allow sufficient time for the solvents to evaporate and you can assist this
by increasing the airflow around the paint. The disadvantage of increasing the
airflow is that you might deposit dirt in the fresh paint. When the solvents
have essentially evaporated, increase the temperature slowly.
You will need to perform some tests to determine the correct flash-off times
and temperature increase.
Best wishes,
Ron Joseph
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