Booth extractor fan

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  • July 5, 2015 at 12:05 am #48877

    im starting a little shop of my own in the next few weeks and am making a booth to start off and if it goes well i will install a proper one in 12 months !
    My question is that i can only fit booth in one corner and the fan needs to go on the left side wall where it would normally be at far end wall ? If you can imagine driving a car into a booth it will need to go about where the fender/wing Of the car is ? Would this work ? I can have an inlet fan filtered towards the back from the roof no trouble so that should be fine it would just be extracted to the far left ?
    Also would it be better high or low on the wall ? Many thanks if you have any advice

    July 5, 2015 at 11:57 am #48878

    Our home made booth is exactly how you describe yours will be.

    We have 4 2×2 inlet filters and 4 2×2 exhaust filters.

    We only have a fan on the exhaust and not the inlet.

    It works fine I only struggle when doing full repaints as the overspray builds up but if I change the exhaust filters before doing a full repaint it is manageable.

    Both our inlet and exhaust are at floor level although I would prefer the inlet to be higher.

    Best of luck starting your own shop.

    July 5, 2015 at 12:16 pm #48879

    Thank you mate ! i was hoping you would see this as i remember pictures of your build from a thread last year !
    I will probably have it a bit higher than floor level and build a box around it for a filter cartridge or cut a piece off those green and white rolls and make something to hold that in place ? Its a case of making do for now but i still want it to work well.
    Do i have to match inlet fan to extractor fan as the extractor im looking at is a proper booth job with motor that sits above so fumes cant get to it ? I was going to use a box fan for inlet but will be smaller would that be a problem and does it have to ballance ? Thanks again
    Carl

    July 5, 2015 at 10:19 pm #48880

    I have no idea about that to be honest mate. I would imagine you need more pull from your exhaust than from your inlet otherwise you’ll get positive pressure which will force paint fumes out your booth into the workshop. I am only guessing though. We don’t have that problem because we don’t have a fan pulling air in we just have filters and rely on the exhaust fan to pull air through.

    We just buy those 2×2 filter squares as they are cheap enough when bought in bulk from Dalby. We made the booth doors to fit 4 of these in and built an exhaust box with the fan in that also has 4 filters.

    Are you doing this full time or just trying it part time to see how it goes?

    July 5, 2015 at 11:01 pm #48881

    Its gonna be full on mate ! I have a pal who runs a tiny two car pdr and paint shop but it is very very successful as its in a perfect spot! He cant turn work out quick enough so he subs work out to a shop the other side of Birmingham, hes gonna give me that work now but also he is gonna rent a single space off me to do pdr training which he does a lot of and that single space will cover my weeks rent ? So i have a bit of a plan to get it flying mate just need a bit of my own work to top it up lol ! Also im renting my unit from a good little car sales pitch who will give me bit n bobs too ? What you think ?

    July 5, 2015 at 11:04 pm #48882

    How clean do your jobs look say a black car ? What clear do you use for air dry / ir lamps mate ? At the shop im working in they use valspar but id like to step up to a better clear ?

    July 6, 2015 at 7:06 pm #48883

    I had a similar problem.

    The only place where I can exhaust out is halfway along one wall but I don’t have the space to make the booth wide enough to do that. So, I put the plenum chamber, which has fan mounted above it, at the end and then ran ducting up into the ceiling and back along the side to the point where it can go through the floor above and up to the roof.

    The ducting is boxed in along the right hand side ceiling, sitting a little below the original ceiling level. It makes the booth end draught which works well enough. Fan is designed for the size at about 14,000cf/minute so sucks the booth clear very quickly and end draught means a fairly constant wall of air movement from one end to the other. Inlets are on the doors.

    You could, if you have the width and some ducting, get clever and do a side down draught which would be better but inlets would need to be in the ceiling and you’d need to plan air flows fairly carefully. I didn’t have that option.

    [IMG]http://i589.photobucket.com/albums/ss334/cprscc/Painting/Booth002_zps39c5be9e.jpg[/IMG]

    July 6, 2015 at 11:11 pm #48884

    That is a smart home made booth. I wish ours looked like that!

    We air dry all our jobs in the warmer months and in the winter we have central heating which keeps the booth warm enough all night to cure jobs. I can paint 2 or 3 jobs a day if I’m on a roll leaving one in the booth over night to cure and a couple in the workshop with the masking pulled off.

    I don’t use infra red lamps much apart from drying filler and spot primer but they do work well but expensive if you buy a set up rather than making your own.

    We use Glasurit HS for direct gloss and usually use Lechler Macrofan 2000 HS clear coat. MS would work better in our set up but I actually prefer working with HS.

    My jobs are usually pretty clean. Sometimes I don’t polish them at all, sometimes just a handful of nibs and sometimes I give them a general polish all over. That’s usually when the workshop and booth is ready for a clean out.

    I always wash cars before doing paintwork which I find helps a lot with avoiding dirt in paint. I use a washable spray suit which I wash often and always give a good shake before doing a job. I use an old tack rag on my airline and gun before starting as well.

    July 6, 2015 at 11:25 pm #48885

    Thanks guys invaluable information ! The shop has a mezzanine above where i will have a booth so i might put fan up there and drop ducting down with a box fitre the whole height of ceiling to floor ? Then a ceiling intake with filtered but it wont be too wide as it has beams that may be strucural so not sure yet if i can cut some out or not ? I will let you know how / if it goes !
    How do you find the Lechler hs 2000 for die back and how it sprays ? Do you thin it 10% ?

    Carl

    July 6, 2015 at 11:27 pm #48886

    [quote=”NFT5″ post=37305]I had a similar problem.

    The only place where I can exhaust out is halfway along one wall but I don’t have the space to make the booth wide enough to do that. So, I put the plenum chamber, which has fan mounted above it, at the end and then ran ducting up into the ceiling and back along the side to the point where it can go through the floor above and up to the roof.

    The ducting is boxed in along the right hand side ceiling, sitting a little below the original ceiling level. It makes the booth end draught which works well enough. Fan is designed for the size at about 14,000cf/minute so sucks the booth clear very quickly and end draught means a fairly constant wall of air movement from one end to the other. Inlets are on the doors.

    You could, if you have the width and some ducting, get clever and do a side down draught which would be better but inlets would need to be in the ceiling and you’d need to plan air flows fairly carefully. I didn’t have that option.
    Are those booth lights explosion proof mate ? Where i work at the moment they just have bare strip lights everywhere lol
    [IMG]http://i589.photobucket.com/albums/ss334/cprscc/Painting/Booth002_zps39c5be9e.jpg[/IMG][/quote]

    July 13, 2015 at 4:42 pm #48887

    Explosion proof lights? :rofl Don’t be silly. 😛

    Actually the majority of the lights are separated by a diffusing lens, only the 4 single fluoros are exposed and they were just supposed to be temporary. I’ll change them…..one day.

    Jack, what you do sounds almost exactly like what I’m doing, except I’m using MS clears. Agree 100% on washing cars before painting – that alone cut down the amount of dirt in the paint by a significant amount and with a bit of care, like you, I get very little dirt in the jobs so most can go out straight off the gun.

    July 14, 2015 at 2:16 am #48888

    Havent been able to get on here as the server has been down !
    Does anyone know a cheap ducting company preferably midlands based ? I like the canopy with the filter you have so would like a similar thing ?

    July 15, 2015 at 7:25 pm #48889

    If you go for something like mine, a couple of things:

    That plenum chamber is designed to go through the wall. As you can see from the picture there are windows above the panels at the end and those windows go down to floor level so I couldn’t put it through the wall but had to sit inside the booth. That creates some dead areas around that end of the booth which I think I could fix by cutting into the sides of the plenum, next to the two small benches, either side.

    The fan in that unit is 3 phase (415 volt) and the whole system works really well although it would be even better if it didn’t have to push the air through about 10 metres of ducting. Getting a fan unit that will move the amount of air you have in your booth really is crucial to performance. I’d recommend that you spend the extra – you’ll appreciate it later. The filter pad itself is just cheap polyester wadding from the local sewing supplies shop. I have to change it every week so this works out much better than the proper spray booth stuff. Inside the plenum is almost as clean as the day I installed it 5 years ago, so it definitely works.

    July 15, 2015 at 11:16 pm #48890

    Thank you nft5 and jack for your time !
    So are you saying that if poss to have filter flush with the wall and then behind the wall have it exhaust up and out ? Would that be how you would have yours if you could ? I do have lots of space after the wall so can set it up that way ? Also would a greater surface area be better for the filter that would sit flush at the wall ?
    By the way the fan i have in mind is a 3phase 3kw 1440rpm motor. The motor is mounted on top so no fumes can get to it.The blades on the fan are about 66 cm tip to tip ? He doesn’t know the cfm rating tho ? Is there a way of working this out ? I will know the booth dimensions for definite on Monday and lay out too as it has changed since my first post ?

    July 16, 2015 at 3:12 am #48891

    Yep. Behind the end wall would be ideal for that plenum. Then exhaust straight up and out. The less bends the better.

    That fan sounds like it might do the job. You can get the cfm rating from the manufacturer. The idea is to get a wall of air moving through the booth at the speed that you want. Here, the Australian Standard is 0.5m/s and that works pretty well. To work out what you need, the calculation is:

    Height of booth x width of booth x speed of air movement x 60 = Cubic movement per minute.x 60 = cubic per hour

    So, for my booth (which is 3.6m wide by 2.7m high and required speed is 0.5m/s) that would be:
    2.7 x 3.6 = 9.72 x 0.5 = 4.86 x 60 = 291.6 cubic metres per minute x 60 = 17496 cubic metres per hour

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