Spray Booth Air Intake in a Hot, Dry Climate

Using shop air conditioned by an evaporative cooler ("swamp cooler") should allow good finishing results, rather than drawing in baked-dry outdoor air. June 30, 2007

We are concerned about the fresh air intake of our new spray room. Should we take air from the shop or from the outside? Our new room will be 20' x 20' out here in sunny hot AZ. Unlike many out there dealing with finishing rooms in cooler climates with heated shops, our shop is naturally heated ;-).

We are thinking about taking air from the shop (swamp cooled). When it's 115 degrees and 6% humidity will be the best choice. Additionally, it could be $2k less to take air from the shop rather than outside. We are looking for suggestions. How are others in Phoenix set up?

Forum Responses
(Finishing Forum)
From contributor D:
Wouldn't the swamp cooler make the air in your shop more humid, thus raising the humidity in your shop? I lived in Tempe for 10 years and had a swamp cooler on my house.

From the original questioner:
That is correct. The swamp cooler or evaporative cooler definitely adds humidity. However, when it's 110 degrees and 6% humidity, the moisture produced is not that bad and can be welcome. Imagine taking that outside air into your finishing room. It could get a little toasty in there, not to mention the effect on the finish. But then I guess that's the point of my question. Finishing in the early hours of the day may be a consideration as well. I'm just glad the summer is only 3 months out of the year! Thanks for the point of clarification.

From contributor B:
Whatever humidity is involved, it certainly isn't like it is here in the deep south. We finish consistently in the 90's and produce good finishes. So in my opinion, you aren't going to have any problems with humidity that low.

From the original questioner:
Totally agree. I believe my problem is the exact opposite. If I suck in hot dry air, the material will dry before it hits the surface. It can be like an oven out here. The outside air would be from the roof, so if it's 110 on the ground, the air on the roof could be 170! So how do shops out here set up and operate their booths?

From contributor E:
Your best move is the swamp cooler. Additionally you'll need to modify your paints using MAK (methyl-amyl-ketone), aka super sauce, to get any flow out of them. Where are you getting your coatings? S-W, Akzo Nobel or A. G. Layne?

From contributor J:
New guy here from AZ too. I spray year round here in Phoenix and use my cooler until it gets too humid in the monsoon season. I then either suffer with the water off or turn on the A/C and then vent it out quick once I'm done spraying.

I spray Frazee lacquer exclusively and have had no problems with it lighting off too fast in the summer. Granted, you really need to hustle and preferably use an airless, but I can stay ahead of the game. Nice thing about the heat is I can re-coat in about 2 minutes!

From contributor E:
The Frazee is actually Valspar coming out of LA. Same stuff I get from A.G. Layne. MAK will help your flow out in summer a lot. 4 oz/gallon works great.

From contributor J:
Thanks. I'm using the WW55040 lacquer since the WW680 series is now discontinued due to the VOC content. Tried the 550 today on a kitchen and so far, so good. It's very white and thin as water, but went on good, laid down nice and dries super fast. It's loaded with acetone and very strong compared to the 680 I'm used to. Oh well, progress I guess. Maybe it's time to try some water lacquer (yuk!). Times are changing.