Ask the Expert Question-and-Answer Archive

by Ron Joseph

July, 2001

Using HVLP Spray Guns for Auto Refinishing

Q. I'm a hobbyist - primarily automotive finishes. I will do one or two cars a year just for fun. I've used the traditional high pressure siphon spray guns for many years, but "think" I want to go to HVLP. I just shoot in my home garage so I do have some limitations. I don't do repairs on new cars for people expecting factory results. I do my own cars and some repair for others, charging only for materials. I have a 5hp, 33 gallon tank compressor that delivers 12 CFM at 40psi.

HVLP questions: Would HVLP be a good match for my use? If so, could I get a decent gun at a reasonable price (under $250)? From my reading it sounds like having everything just right (orifice size, air pressure, distance from surface, fan width etc) is critical or one will end up with disappointing results. Is HVLP spraying that much more sensitive to variables than is standard spraying (I'm a little scared of HVLP -justified?)

I'm drawn to HVLP because I was hoping it might cut down somewhat on the "fog" created by standard spraying (can really fill a garage quickly - even with the doors open); had heard that metallics were easier to shoot with HVLP - less need for mist coating to avoid blushing; and could cover more surface with less paint use (because of the proported 50-65% increase in material transfer).

Do you think I should pursue HVLP? If so, what advice would you offer regarding gun purchase and use? Thank you!

A. Unfortunately, I can't go into great detail because of time constraints, but I can tell you that HVLP is being used both in the auto refinishing and the auto assembly (OEM) industries.

If you set up the spray gun correctly you will significantly cut down on the spray "fog" or overspray, and since you are painting in your garage, that might be a great advantage.

The general rule in life is that you get what you pay for; inexpensive spray guns don't give you the same quality as the more expensive ones. You might look at eBay for a good secondhand HVLP professional gun.

To use HVLP you will need a compressor that can deliver approximately 25 cfm at 50 psi. Your existing compressor might not have sufficient capacity to give you a quality job.

Before you purchase a gun and use it on your, or someone else's car, I suggest that you visit a local body shop or job shop and ask them if you can try out the gun on some clean metal sheets.

Hope this gets you going.