Paint Booth Lighting

Hi all,

I built a pvc pipe and plastic spray booth in my garage. I used inlet and outlet filtered fans. It all works pretty well except for the lighting issue. I have been using Stewart systems 2-part waterbourn urethane. The paint is pretty good stuff with minimal toxicity. The key to getting a "just like it came from the Mercedes factory" finish is in the fourth and final coat. It has to be thick enough to blend together into a smooth surface but not so thick that it runs. The only way you can really get it right is by watching the paint go on in a glare line. Therein lies the problem.

I was using a two head halogen shop light shining through the plastic. Just couldn't seem to get a good location for the light to get that glare line. Any suggestions? What have other people used to light the booth?

Regards,

Michael Wynn
RV 8 Fuselage
San Ramon, CA

I went to home depot and got one of those four-foot flourescent tube fixtures that hold two lights. I then built a vertical stand out of 1 by 2 lumber. I actually built two such units, but I mostly use only one. I position it well to the right of whatever I'm spraying and try to keep my head to the left of the gun and the work and look towards the light.

Dont blow yourself up

Many folks put the lights in the booth. There is a reason that a two lamp paint booth fixture costs $1500. The issue is two fold; VOC's getting into the fixture and accumulating, kind of like a pressurized bomb waiting to go off, the second is a spark getting out of the fixture in a dense VOC environment.
Hundreds, if not thousands, of RV's have been painted with Home Depot strips, or worse enclosed fixtures, and I have never heard of anybody getting hurt. However, someday it will happen, and when it does, it wont be pretty.
You can check out some nice solutions in these posts from guys like Randy Lervold who did their own thing. The key was a volume of space, and great airflow to keep fumes from accumulating or building up. Airflow is also critical to keep the overspray from settling back on your work. I believe if you have enough flow, the VOC's can not build up to a dangerous level. That means a lot of square feet of filter, or none at all. My shop had no input filters. Yes, there was some contamination from time to time, but airflow was always excellent. Some of the nicest paint jobs I have seen where painted in open hangars, with a due amount of elbow greese color sanding later.

Lots of 4' fluorescent lights on stands made out of 2x4's INSIDE the booth. I think we had four lights inside the booth when painting my car.

Stewart Systems Paint

JonJay said:

Many folks put the lights in the booth. There is a reason that a two lamp paint booth fixture costs $1500. The issue is two fold; VOC's getting into the fixture and accumulating, kind of like a pressurized bomb waiting to go off, the second is a spark getting out of the fixture in a dense VOC environment.

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JonJay, Stewart systems paint is a waterborne paint and is "non-hazardous, and non-flammable," per their web site (http://www.stewartsystems.aero/). Correct me if I'm wrong, but I believe that means non-explosive too? Sure eliminates a lot of safety issues while painting...

This is what I did: I got a fluorescent hand held "trouble light" from Sears. I hold the light with my left hand while running the spray gun with my right. Between bobbing my head and moving the light, I can paint "in the glare" and much better judge how the paint is flowing out. This has greatly cut down on runs. Any bright light will work but a fluorescent light is safer (cooler and less likely to break if dropped) than an incandescent light bulb.

Ditto on the handheld light!

Stephen Lindberg said:

This is what I did: I got a fluorescent hand held "trouble light" from Sears. I hold the light with my left hand while running the spray gun with my right. Between bobbing my head and moving the light, I can paint "in the glare" and much better judge how the paint is flowing out. This has greatly cut down on runs. Any bright light will work but a fluorescent light is safer (cooler and less likely to break if dropped) than an incandescent light bulb.

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After adding lights outside the booth after each round of painting, I finally started using a florescent shop light. I started using it as I painted the bottom of the fuselage, where there was NO light glare to use. I liked it so much I used it for the rest of the plane. I was painting with Imron and a prefilter in the booth with positive pressure intake fans in a standard PVC and plastic booth.

Sebastian Trost
RV-7A flying!
170 hours
Cameron Park, CA

Class 1, Div 2 Lights

I recommend you use a good quality color corrective lighting system in your paint booth. There are many great brands out there, I've personally had good luck with Nova Verta's light fixtures. Check out there lights in their parts page.

Color comes from the lamp.

jjchavez said:

I recommend you use a good quality color corrective lighting system in your paint booth. There are many great brands out there, I've personally had good luck with Nova Verta's light fixtures. Check out there lights in their parts page.

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Use a triposphor lamp in the 8xx series, like an 835 (relatively warm color) or an 841 ( cooler color). They will give you excellent color rendition. You can use them in any fl fixture.

Class 1 Div 2 fixtures are not rated for Paint Booths, that would be Class 1 Div 1, which nobody can afford. Class 1 Div 2 is a rating for Hazardous locations where explosive gases are normally not present, only have the potential to be if something goes wrong. In fact, in certain conditions, Class 1 Div 2 fixtures can be more dangerous as concentrations of gases can build up in the fixture to higher concentrations than in the room are area itself as the fixtures are sealed against dust, but not very well against gases. A hot fixture being turned on and off can suck the vapors into it. If there was a source of ignition in the fixture, like a bad socket or accidental lamp breakage, you now have a small bomb. An unrated fixture will not build up those concentrations as they are not sealed. Sound counter intuitive?
A lot wrong has to happen to blow yourself up regardless. You need a high concentration of explosive gases and a source of ignition, like a spark from a motor or a lamp breakage. It is very rare, but people have, and do, blow themselves up.
Make sure whatever area you are painting in is very well ventilated and you have no issues regardless of fixture type.
PS - I make my living selling lighting fixtures. Does not mean I am an expert, just a good salesman - ha!

jjchavez said:

I recommend you use a good quality color corrective lighting system in your paint booth. There are many great brands out there, I've personally had good luck with Nova Verta's light fixtures. Check out there lights in their parts page.

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I have to ask... Why? Once you've picked your paint colors, isn't the important thing just to have enough light in the booth? How does better color rendition during the painting process change the quality of your paint job?

I used to design and sell lighting. I once sold a fixture to a cheapskate who was painting the *inside* of water tanks (the big ones that serve an entire town). He told me that there were constant mini explosions while they were working in there. He was a cheap and abusive boss, so he didn't mind that his employees had to suffer these danges.

What does this have to do with painting RVs?

First, don't put the fixture inside the booth. Paint shop booths have the fixtures outside shining thru a window for just this reason. (Can use ordinary fixtures because they are located outside the dangerous environment.)

As to color rendition, it makes a huge difference no matter whether you already have the paint picked out or not. Nuances count with paint. To see what I mean, imagine painting under those high-pressure sodium (orange) street lights. Heck, I have trouble figuring out which car is mine under them.

835 and 840 refer to the color temperature of the tubes in degrees Kelvin. The combo is indeed the best mix, IMHO

8 is the series, 35 and 41 are the color temp

mculver said:

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835 and 840 refer to the color temperature of the tubes in degrees Kelvin. The combo is indeed the best mix, IMHO

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The first digit is the series, the second two are the color temp as you indicate.
8 Series are premium lamps, typically triposhphor. 735 and 741 ( 7 series ) are more common but do not provide a very high CRI (color rendering index).

Not sure what impact they have on painting RV's but for the few extra $ the 8 series cost, that is what I would use. I have 835 in my hangar and love them.

Hey Mike - who did you used to work for up there? I know a lot of lighting people in the Seattle area.