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I live in the South, and rare is the day it is not humid. If it is not humid, then it is cold.

I just finished my spray booth out behind the shop. It is 10x12 (I also store some wood and a HD Hog out there.)

The booth has a Jenny Fan (explosion proof) and a 20x20 filter port. I was thinking of building a filter stack that includes a one inch layer of desiccant beads.

Does anybody think this would work? Got any other ideas?

Mike

My desiccant filter has about 12 inches of beads. I bought it from Grainger for a little over $100. I build a lot of my own tools but wouldn't try to build this. Remember, the filter will be under pressure.

I did not know they sold these.. Link? I think we are talking about different things. I do not mean for a compressor. I mean for a room.

Oh, well that will never work. You would need a huge filter to remove that much moisture. A dehumidifier is what you need. In a small space like that, the unit wouldn't have to work that hard. However, the problem you will run into is makeup air will be unconditioned. Nothing you can do about that. I have my spray booth in an attached garage and I draw makeup air from my house so I have a large reservoir of conditioned air. As soon as you start your fan you will be blowing humid air over your workpiece and will have to deal with blushing. One way to do that is use retarder in your mix.

Having a filter with a few beads that the makeup air has to travel through will place a restriction that will slow down your exhaust a bunch. I just don't see that ever working. I am basing this opinion on years of engineering experience, some of which included systems for moving air.

I could run a 6" or 8" flex pipe from shop to shed, only about 4-5 feet. You think that would work? Shop is air conditioned. Just run fan when I am spraying.

Your 20" x 20" fan would be bottlenecked by the 6" flex pipe. Do you realize the restriction that would cause? 400 square inches throttled down to 28 square inches. I simplified the math but it would definitely kill the flow.

Yeah, maybe two 8" hoses. Its not a huge room and the fan is way over specified for that space.

Two 8" hoses would be 100 square inches of cross section area so you are still restricting air flow a bunch. Depending how long the hoses are the wall friction may significantly reduce flow further. You would be better off building a two foot square duct and line it with a smooth interior surface like hardboard. But the shop would be a good reservoir of air to draw from.

Heating the space above the outside temperature will lower the relative humidity indoors. During cooler high humidity days I will heat the spray area or move the object to a heated area after spraying.
Humidity varies throughout the day, so you may find a part of the day that is conducive to spraying material.
As Barry mentioned adding retarder can also help you work in hot, humid situations. It does slow the drying but reduces blushing and helps flow out.

Mike our shop, about 1,000 square feet has a 60 square foot spray both with explosion proof fan and lights.

We use AC and/or heat seasonally dependent to reduce the RH in the shop and then the door to the spray booth has filters in it so the shop air, already RH conditioned goes through the spray booth when we turn on the exhaust fan. It works great for us and no need for a dehumidifier which are not explosion proof by the way and half of them seemingly are fire risks with yet another huge recall active right now.