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  • Setting up a spray room.

    I have an area in my basement I am going to turn into a dedicated spray room for both wood and metal projects. Everything from furniture to machine restoration to motorcycle parts. I've had little success in finding information for doing this. This is what I'm thinking so far:

    - No intention of spraying lacquers at this point. Is flammability an issue with other paints? I use basic enamels and water-based polys now.
    - I'm leaning toward positive pressure if only because the layout for the fan(s) will require less space in the booth.
    - I use HVLP and a Critter (airbrush on steroids).
    - Room size will be about 9'X13' with 9' ceiling.
    - This will be a complete homebrew setup. No commercial booth.

    I can't find any information about CFM requirements (air changes, not for the guns), airflow velocity, filtering, airflow patterns, lighting, etc. Any help or a point in the right direction would be appreciated.

  • #2
    Hey, I know where Kirtland is! Used to live in Mentor and Concord-- Snow belt city!
    Anyway...
    The best place to look is you state's EPA rules. They have all the formulas and specification you need to create a paint booth. In general, you need to change the air at least two times per minute. Three times is closer to spec. This will extract nearly all airborn VOCs and particulets. Your paint will still release VOCs during the dry or cure process.

    I don't have my specs handy but there is also an air speed spec. That's the speed of the air moving through the booth. (velocity) You control this by the size of the inlet and outlet area and the filter sizes on each. Yes, you want intake filters too. Keeps the dust off your fresh paint. The outlet filter catches the solids and the VOCs get ejected into the air. This is the sticky part. In Texas, this exhaust can not have any visible solids. The exhaust point also has to be 12' above the highest building within 150' or 300' if you're on a slope or below the normal surounding grade (your building, not the booth). Of course, this is spec for "businesses" but it's done for a reason.

    Your main concern will be neighbors. Keep them happy with clean air and low noise. One complaint of "paint odor" could get you in serious trouble.

    If you need the specs (for Texas), I can dig them out of the file at work and get back to ya Friday.

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    • #3
      Ken, thanks for the reply. I'm not a commercial shop, but I want to make sure the setup is safe. My usage will be in spurts, as projects are completed. My nearest neighbor is nearly four hundred feet away. I'm not anticipating any problems with odors. Basically, I'm looking for a low-tech alternative to an appliance box and cheapo fan that will give me greater control over the process and allow me to keep working in the shop while finishes dry.

      So with a 9x13x9 room I'm looking at 2-3,000 cfm. I'm aware of the need for intake and exhaust filters. The air speed is trickier. I imagine too much blows the paint around and not enough lets it settle in the room without being exhausted. Is there a calculation based on booth size? I've seen pictures of booths that look like entire walls are covered with filters. I could actually do something like that if needed. I was thinking that the intake ought to be at ceiling level and the exhaust at floor level on the other side of the room.

      What about lighting? The only info I was able to pick up from web research was to mount flourescent strips vertically on the walls. I have no clue if this is right.

      Just a few other details...the room will be insulated and drywalled so as to be airtight (except for the intake and exhaust). I already have a 36" exterior steel door to use. I figured on heating with a couple of electric baseboard heaters. Cheap to install and easy to crank up the temp if needed for drying/curing. I could even put a dehumidifier in the booth to lower the moisture level. (I'd only turn it on after spraying.)

      What did you do when you lived in Lake County? I see you're in the custom car business in Texas now. Miss the snow?

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      • #4
        I think the airflow standard is 100-110 fpm. They make a gauge for this. On a commercial spray booth this is determined more or less by the size of the intake opening. (Of course it's more complex than this, the opening has to be sized to the booth, etc.) So, if you had a 7x7 intake area (49 sq. ft.) and you wanted to pull 100 fpm you'd need an approx. 4900 cfm fan. (plus some to overcome the filters...)

        I'm thinking back on a bunch of this, someone correct me if my numbers are off.

        For intermittent hobby use, half of this might suffice. Still, it's a bunch of air that has to be pulled through the house, presumably through an open door. This is a big problem for paint shops, they need "make up air" and in the winter they need heated make-up air, which is very expensive. It wouldn't be very hard to figure out how many times an hour you'd 'replace' the air in your house. This might be a big problem.

        Lights are supposed to be 'explosion proof.' The portable ones are flourescents in thick glass tubes, spray booth flourescents are behind glass.

        Finally, spray booths collect overspray more than smells or pollution, as well as keeping painters safe from a potentionally explosive enviroment. Depending on the paint, you'll still have the odors.

        It's a bunch to think about, and probably possible, but for that amount of effort, I'd consider sending work out, or perhaps a 'paint shed' out doors.

        You might try some of the big paint booth mfgs. for more info. Global Finishing, Col-Met, etc.

        Good luck,

        James C

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        • #5
          Take alook at mine, It really works quite well. I can't tell you off hand all the specifics, but you can get the idea.http://img.photobucket.com/albums/v4...2-2231_IMG.jpg

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          • #6
            [QUOTE]Originally posted by daryl bane:
            [B]Take alook at mine, It really works quite well. I can't tell you off hand all the specifics, but you can get the idea.

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            • #7
              Boo Hoo. I looked in my files at work but couldn't find the original specs for my booth. I'll have to do some box digging, I guess.
              Here's what I'm running in my paint booth.
              14' x 26' x 9' Cross Flow
              20 Intake Filters (20x20")
              20 Exhaust Filters (20x20")
              30" Tubaxial fan, 3hp.
              12,500 cfm. (rated)
              2.0 fps. cross flow (rated)
              0.0" vacuum (rated)

              Here's the parts booth:
              11' x 16' x 9' Cross Flow
              6 Intake Filters (20x20")
              6 Exhaust Filters (20x20")
              20" Tubaxial Fan, 1hp.
              4,000 cfm.
              1.8 fps.
              0" Vacuum

              James is right about the lights--They SHOULD be on the outside of the booth. I will say that my "parts" booth (11x16x9) has lights on the inside. My car booth has safety lights. If you're changing the air 2-3 times a minute, you can darn near light a pipe (open flame) in there. That is, if you could keep the flame from blowing out. The dangerous time is during curing/drying when the fan is off. I purge the booth before turning on lights or entering after a shoot. (Turn the fan off before entering, then back on once inside.)

              Also as James states, you'll need a way to provide the "makeup air" that will be exhausted. Recirculation is not an option in a paint booth--Too much VOC and toxic chemical build up. Air treatment such as heating and cooling is done on the intake or makeup air. Don't try to do it IN the booth. You'll plug up or coat a coil unit with paint particles. Too dry is just as bad as too humid. I think dry is worse--I don't like sparks!

              Back in my "hobby" days, I had nothing but a 20" box fan stuck in a window blowing out (no exhaust filters). I had 3 20x16" intake filters in a holder covering another window. That was Prime painting conditions compaired to the usual garage or back yard.

              There's no need to force-dry paint unless you want it in hours. In most cases, I let all my stuff sit in the booth over night. By morning, I'm sanding or buffing (depending on what coat) or putting it together.

              After all these years of painting, I will say you can never have too much light or too clean of INPUT air. Paint booths have the lights running vertical on the sides because the panels run vertical. The upper lights run horizontal for the same reason. Place the lights where they're out of the way and do the most good. For make up air, you can open another basement window. Make your booth simple and lay some coats!

              Oh yea, I worked at the Cleveland Clinic back in those days. Programming Manager then later Tech Services Manager in the IT division. Later went into consulting with Systemation, Inc. ... that later got purchased by Cap Gemini America. Gosh, those were the days... Miss the snow? Yea, like I miss corporate reorgs. I spent 17+ years up there (NE Ohio) then I came HOME!

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              • #8
                One phrase: STATIC ELECTRICITY. Regardless of the paint medium any spraying opperation will create static electricity, thus you need to ground as much stuff as possible for your own safety. Most spay booth fires are caused by static electricity and feed by poor housekeeping and booth maintance. The use of water borne paints reduces a lot of problems but you will still get paint build-up and thus you will have fuel for a fire. Any oil based or urethane based paint will be cut with solvents thus you have flammables before you start to spray as well as the increased risk as you spray. To cover the electrical code for this would take up tooo much space. You should be able to get it at you local Library The N.E.C can be found in both B.O.C.A. and NFPA documents. The NFPA is sort of the keeper of the rule so you would want NFPA 70 then look for Classes 1&2, Divisions 1-4 as this covers hazardous locations.
                If you are in an enclosed booth and are using any kind of epoxy finish, supplied breathing air is a must or you won't be will us for long. This requires special filters so you can not just use you air compressor to breath with as you paint. The use of a cartrige breathing mask is the minimum for all other booth painting, unless you wish to feel like you were just at a Grateful Dead concert when you finish. As mentioned before, the heating of the booth air occures outside of the booth before the intakes. In a commercial setting this is usually from steam or hot water coils in the dedicated duct work. work safe and everyone will be happy

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                • #9
                  Spoken like a true Fireman ARFF!

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