Ask the Expert Question-and-Answer Archive

by Ron Joseph

July, 2005

Spray Painting CARC Coatings

Q. Could you tell me what the best kind of spray painting gun would be for using CARC. A regular spray gun, or a high volume low pressure spray gun? Our customers are having a problem with spraying CARC.

A. You can use both a conventional or an HVLP spray gun. The conventional gun will break up the paint better, but your transfer efficiency will drop as you increase the atomizing air pressure. This implies that your costs will go up dramatically in terms of paint usage, replacement of spray booth filters, disposal of hazardous waste, etc. In some states conventional spray guns are banned by the EPA, so please check if your state bans this gun.

HVLP is more transfer efficient and will cost you less in terms of the parameters mentioned above. To apply CARC through an HVLP gun you need to lower your fluid pressure so that the 10 psig atomizing air can break up the paint. Your painters might need to move more slowly, but you can achieve a good looking finish. Insure that you use a 3/8" air hose from the regulator on the spray booth wall to the handle of the spray gun. DO NOT use 1/4" hoses or QD fittings!!!!!!!

The main problem with HVLP is that painters have not been trained how to set up the gun properly. We do offer an on-site training program and if your are interested please go to http://www.ronjoseph.com/hands_on_small_cos.htm

Also, you might be interested in learning lots more about the application of CARC and other painting operation topics by attending a class to be held in Santa Fe, NM on September 27-29. See http://www.ronjoseph.com/po.htm.

Best wishes,

Ron Joseph