Ambient Temperatures and Pre-Catalyzed Finishes

How cool is too cool when applying pre-catalyzed finishes? April 30, 2006

Question
It's been cold and my shop heater can't keep up. What is the lowest temp I can spray SW pre cat at?

Forum Responses
(Finishing Forum)
From contributor T:
Most data sheets on precats say not to apply below 65 degrees, although I have seen shops spraying at 55 degrees. This spec is typical because the coating's viscosity will thicken, and flash off times will increase with cooler temps.

Two things will help you, the best being a heated air make-up unit. This will supply heated air in a quantity in surplus to what your booth is sucking out. If it is an enclosed booth, you could even pressurize the booth (giving you a clean room effect by repelling outside dust away) or add a bake cycle to the unit, which will allow you to bake items in your booth after spraying (under 145 degrees) for a timed cycle. The second option, and less expensive, is to get a heater for your coatings. This will allow you to control the viscosity of the coating, but will help with dry times very little.

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From contributor R:
Call Sherwin Williams directly and ask them this question.

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From contributor G:
You may be able to spray it cold and it may even dry, but it won't cure until it warms up.

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From contributor O:
We sometimes spray SW precat as low as 50, without problems. Takes a little longer to dry and cure (it does cure). Looks and performs great. Almost like it that way when spraying red oak as we get no solvent pop. You may think about creating a drying room. We sometimes spray in a 50-65 degree and then roll our finishing racks in a small plastic-offed room that we superheat.