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Thread: Help with basement spraying

  1. #1
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    Help with basement spraying

    I want to get into spraying and have decided on an HVLP turbine unit - details TBD. I plan to spray waterborne finishes with the exception of shellac, which would be done in the garage or outside.


    The main obstacle I have is where to do my spraying. My shop is in an unheated/uncooled garage and I don't really have the space for a spray booth. I also don't want to deal with moving and storing a tear-down booth.


    I have a room in my basement that is well-lit, dry, and available. I would like to set up a booth in there, but there is no ventilation. Ideally my booth would be 5' x 5', with 7' ceiling. I can make it open at the entrance, or enclose it.


    I could run a duct outside from this room with a dust collector or some sort of inline fan to pull air out, but I don't like the dust collector route because of the noise. I do not have the space for more than about a 6" duct (i.e. I can't put a big fan in the wall).


    Wearing a respirator with the appropriate cartridges is a given, and the room is well enough sealed and insulated that I am not worried about toxic stuff spreading elsewhere in my home.


    My questions are: would a 200-300 cfm inline fan provide enough airflow to vent the harmful stuff? Would it offer any assistance with overspray? Would two inline fans increase the airflow? Anything else I should be thinking about? Any other suggestions?


    Thanks.

  2. #2
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    Don't be too quick to dismiss spraying in your garage/shop. I do a lot of spraying in a regular shop space, without a booth. I just use a drop cloth on the floor. If you're spraying finishes intended to be sprayed, they get dust-free very quickly -- like ten minutes or less. That is, they're not likely to grab a lot of dust and bugs and such from the air. Also, the spray droplets dry in mid-air, so by the time they get from your spray gun to other machines, they'll be dust.

    Here's a post showing my HVLP spray process. Notice there's no booth. http://www.sawmillcreek.org/showthre...spray+spraying

  3. #3
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    Thanks, Jamie. I did read your post before I asked my questions. I'm not ruling out the garage, but I like the idea of the basement because it is a fairly constant temperature, always dry (dehumidified), and not prone to people and dogs coming in and out. Connecticut is weirdly humid, even compared with your area (I lived in Monterey for a couple of years), and my garage is no exception. It also gets below freezing in the garage in the winter, which I can't imagine would be good for things made with water.


  4. #4
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    Your garage would work some of the year, but not in the Winter w/o heat unless all you spray then is shellac. Waterbornes have a minimum temp. requirement, usually at least 55 F and often higher.

    To answer your question about 200 - 300 cfm carrying away the nasty stuff, yeah, sure it will, eventually, but it won't be enough to prevent overspray from landing on your work and if you spray long enough the cloud will be so thick you won't be able to see what you're doing. I use my 1200 cfm dust collector fan through a 5" hose to exhaust my temporary basement spray booth, which is nothing more than 6 mil plastic hung from nails in the floor joists and paper on the floor. Jamie may be able to spray with no booth but I'd have a mess if I did that. I've already gotten over spray on some equipment about 3' away from the open end of my booth and had to spend considerable time removing it. I also spray a lot of shellac toners and when they find their way to any uncovered floor I have a permanent reminder of what color it was. Setting up a temporary spray booth takes me 10 minutes tops and, since it's just sheet plastic, takes up almost no space to store it.

    5' x 5' would be at least 3' too short for me, but it may work for you if you don't spray anything very large. On the other hand, taking things down into your basement just to spray them is going to get old unless they are pretty small. Also, if you spray in your basement whatever amount of air you exhaust you have to provide as makeup air as well. If you don't plan for it that air will come from down your chimney or some other undesirable source.

    If you plan to spray anything very large I'd look to set up a temporary spray booth in your garage and add supplemental heat in the Winter when you want to spray. In your garage you could use one or two box fans to push air through a filter into your booth so it's under positive pressure. That would get rid of any bugs and large dust particles and keep both from getting on your freshly sprayed work. My friend takes a different approach. He uses a large HF 30" pedestal fan at the front end of a 3 sided sheet plastic temporary spray booth. The fan blows exhaust out the open garage door. There are no filters in front of the fan. A man door on the other side of the shop provides makeup air. So far he has not had any issues with dust or bugs getting onto his freshly sprayed pieces.

    John

  5. #5
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    John,

    Thanks for your reply. I hadn't considered the air coming down the chimney aspect. I could let in air from somewhere else but I think that would always be a concern. How do you avoid this when pulling 1200 cfm out of your basement?


  6. #6
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    I can't imagine spraying in a basement without a proper way to vent out and return air. If you could knock out a section of wall for an exhaust fan at the minimum (that could be closed off otherwise) and provide replacement fresh air while you are spraying then I think you can make this work but without - just trouble. Even with waterborne there is nasty overspray no matter your personal protection. The garage has more potential though your winter options are limited. I live in coastal Maine - same boat as NE CT but less hot (in the summer), maybe equally humid but colder in the winter. I use a 10'x 20' tent in the summer with a HF fan at one end and a different finish or a friend's shop in the winter. No good choices otherwise.
    "... for when we become in heart completely poor, we at once are the treasurers & disbursers of enormous riches."
    WQJudge

  7. #7
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    I used to leave the shop door open and then open a window in the house at the top of the stairs to bring in make up air. Trust me, if you don't provide for make up air, it will pull it down your chimney, or pull smoke out of your woodstove. Guess how I know? Anyway, when I got tired of going up/down the stairs, I knocked out one of the glass block windows at the other end of my shop and installed a vent window. The exhaust from my DC goes out a window right behind my temporary spray booth. I can and do regularly spray for an hour w/o problems and w/o the temperature in my shop dropping off much even in the dead of Winter. The boiler runs a little more to keep it warm, but there's so much mass in the foundation that the effect of the cold air is damped.

    I only suggested using your garage because your 5 x 5' room in the basement would be far too small for my needs. But if it meets your needs, by all means, use it because having a climate controlled place to spray is a huge advantage. However, you need a lot more airflow than you were considering unless you only want to spray jewelry boxes and other small items with a detail gun. I don't know how you'd spray anything much larger actually. I get by with 1200 cfm with my spray booth, which has an open area of about 50 sq. ft at the front. That's far less than what a commercial spray booth would be for that size frontal area, but it works. Good luck whatever you decide.

    John

  8. #8
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    If you use the basement you must have adequate ventilation but when it comes to it, any booth must have adequate ventilation or it won't work. To avoid the intake air being drawn down the chimney, set it up as a positive pressure booth ie fan force the inlet air and duct out the exhaust air. Cheers
    Every construction obeys the laws of physics. Whether we like or understand the result is of no interest to the universe.

  9. #9
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    Thanks for all the replies. You've helped make my short term decision easier: I will figure out how to make spraying work in the garage. I actually have a heater in there but it uses a lot of electricity and I was hoping to avoid running it for hours just to spray for an hour. The humidity worries me as well, but I guess we'll see.

    Thanks again for all your expertise.


  10. #10
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    I use a temporary spray booth that is just painters drop sheet draped over ropes that are slung between the two walls of my shop. I only spray oil based polyurethane, so the tacky stage is about 4hrs long. I'm also in an unheated garage, with limited storage space (one half is the workshop, the other half sometimes gets the car in it).



    It costs me CA$6 to setup the booth (masking tape and drop sheet), and I go through a $5 pack of the cheapest 20x20" furnace filters per litre of spray (unthinned, so ~1.7L of sprayed urethane). I have two 20" box fans (the cheapest I could find), the "intake" at the back of the garage with 4x pleated HEPA filters on it, and the "outlet" side I use the cheapest filters I can buy - anything solid cloth plugs up VERY fast, and the open fibreglass mesh ones capture the vast majority of the overspray - without the filters there's a huge amount of fog in the garage! I use a HVLP touchup gun, as the piece I spray are quite small - I use aerosol cans for touching up the endgrain (they hang vertically, with the endgrain at the top and bottom, so the ends dont get much spray). My total installation cost was under CA$50 for two fans (on special), two 50' ropes, 8 eyebolts and 4 cable tensioners.


    Outlet filter

    I was running just one filter on the intake and outlet, however the fan couldn't blow enough air through the intake relative to a clean filter on the outlet, so I'd start of spraying with the walls sucked in, the outlet filter would then get clogged up so the walls were bulging out from the internal pressure by the time I was done with a spray session. Using 4 filters (top, sides, front - bottom is plastic sheet) gives me neutral air pressure inside, and the outlet filters actually clog up much slower - I can spray 6-8 sessions with 4 filters vs 4 if using them standalone.



    With the amount of overspray on the walls and floor, and the huge volume of it in the filters after just half a batch of spraying I wouldn't want to be spraying in my garage without this setup.

    I use a couple of continuous photography lights on the outside on light stands to light up the inside. The high quality light really lets me see how things are looking

    In winter when its -15c or cooler in my garage I can heat the booth with a $15 fan heater to 30-40c very easily, even just that thin plastic wall really helps keep the heat in. Being able to recirculate air around the garage lets me run the heater outside the booth for an hour or two to get the temp above freezing, then the air is just recirculated around so it doesn't loose much heat. Once i'm done spraying I put the heater in the booth and turn off the intake/outlet fans, then crack the garage door a few cm for a few hours to let the fumes get out - at which point the garage can drop to -20c to -30c pretty quickly, but the booth is toasty and warm. In summer I just have the garage door open to about the height of the fans and have virtually no smell inside when i'm done. I always wear a 3M respirator with P100 cartridges in when spraying, just have to see how much backsplatter is on my arms/hair/glasses to know I don't want to be breathing that stuff in!


    You can see the ropes I use here, I just setup the booth again last night.


    There's one long length of plastic all the way around, and one length of plastic to make each side wall. I tape them all together with the cheapest masking tape I can find, as well as cutting small slits in the left wall (against the garage wall) and floor every half metre or so and taping over it, so as to tape the wall/floor to the ground.

    Cleanup is a breeze, just throw all my spent filters into the middle of the booth, cut/tear the plastic down, and bundle it all up, then take it to the bin. 10 minute tear down, 1hr setup. The ropes are high enough that I can bring the car in with the ropes still in place.

  11. #11
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    Mark,

    Thanks for the incredible detail and pictures! You've given me some good ideas.

    It looks like you're photographing whatever it is that you're spraying. Do you do sell your work?


  12. #12
    Join Date
    Jul 2014
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    I do sell my items, next week it becomes my full time job. Its going to be fun expanding my product lineup.

    The photography lights are there because the garage is very poorly lit, and it's a rental. There are just two lamps in the garage (the one you see in the roof in the first shot.. barely enough for a bedroom let alone a workshop!), so not enough light to work from. I received permission to add a bunch of surface mounted power boxes all down one wall, and add 220v, but not lighting. This year I built all new benches with lighting built into them, but the tablesaw/bandsaw still don't have enough light - so I have continuous video lights (one LED panel, one quad 105W CCFL) which give me beautiful soft even light over what I'm working on. As an added bonus, having high CRI lamps really improves any in-progress shots I do vs just regular low CRI fluorescent tubes! Lots of light is good, but lots of good quality light is better.

    The photo lamps work really well for the spray booth as I can position them right up against the plastic to get as much light as possible inside. Its really good when wiping everything down with mineral oil to get the reflection from the photo lights on the mineral oil to see if I missed any dust/dog hair/particles on the wood before I spray them.

    I used to do all my spraying in the booth at work, we have a composites lab here. Unfortunately work projects came up and I got booted out, so I needed a spray booth in a hurry and didn't have anywhere to store one... so the rope thing seemed to make sense at the time.


  13. #13
    Join Date
    Feb 2008
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    NE Connecticut
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    I just bought my HVLP setup and I'm still wondering about the basement. It has great lighting, a dedicated room, heat, dehumidifier, and very little dust - everything my garage doesn't have. I really want to find a way to make this work.


    I have done a lot more reading about spray booths and it seems like many people have temporary booths made of plastic sheeting and PVC or wood (as Mark describes, above). They have one or two box fans with furnace filters for the exhaust and an opening (also with a furnace filter) for the intake. There is no exhaust or intake to or from the outdoors. For example:

    outside-480x360.jpg


    I would be spraying only WB finishes, one project at a time. Would the recycled air in the basement, having gone through two sets of furnace filters, be usable? I could potentially bring in a little outside air if I needed to.


  14. #14
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    If you can set up a temporary booth in your basement, where you have year round climate control, that is your best option by far. BUT, you should not recycle the air; you want to exhaust the blower/fan outside and provide for makeup air. Filters on the exhaust is the wrong approach IMHO, they just plug up. But even if you have them they won't filter out the VOC's from the finish, and there are some even in WB products that you do not want to be breathing. Filter your makeup air if that makes sense for your situation; for me it's not needed because the window is 25 feet away and any dust that gets sucked in has time to fall out. If you use a box fan and it gets slagged up after a couple of years because there are no filters buy another one for $15. If you use your DC fan like I have been for 5+ years nothing will build up on it.

    You don't want a little outside make up air - you want one CFM intake for one CFM exhaust. Your heat, dehumidifier will take care of the temp/RH needs. I spray year round w/o large swings in temp. or RH. Keep your booth stupid simple, at least to start with; plastic hung from the floor joists is fine. That way you can reconfigure the layout for the job, if needed, and there's very little to store between uses. Fold up the plastic and put it on a shelf. Disposable paper on the floor. It doesn't need to look pretty to work well.

    John

  15. #15
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    Apr 2017
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    Bucks County, PA
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    I agree with John. I can spray in my basement year round. I use zip wall poles to hold my plastic up and a modified attic fan mounted in a window. Make up air comes in through my shop door from a window on the other side of the basement. No filters needed but I vacuum the shop very carefully before a spraying session. I cover everything I don’t want finish on.

    Here’s a photo looking straight in from the door.

    C82D9AA5-ED0C-490C-8C76-B5EFFA1FE0D0.jpg

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