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Post by merlin on Feb 18, 2008 14:36:37 GMT
OK i,ve been planning to build myself a new spray booth for some time but basically couldn't be bothered with the plans etc , but over the last few days ive sat down and heres what i,ve come up with . its basically a full height stand alone unit set to a height so i can put a bar stool in front , the fans I'm not sure of yet i may use 6 x 120 mm puter fans (12 volt ) less risk of spark or i may use an upside down cooker hood in the base . for the overhead fans again not sure , but these will supply clean air to the unit and hopefully reduce odours and fumes so to all intents and purposes its a downdraft spray booth system . take a look give me your input as it would be appreciated , oh one last thing it will also have quick release manifolds to the right and the glass or perspex is also to reduce escaping fumes and overspray
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Post by popeye on Feb 18, 2008 15:20:32 GMT
Merlin,
if I may add my 2pence's : Wouldn't recommend using top fans for feeding clean air in - all you will get will be a lot of turbulence and a reduction of efficiency in sucking fumes and paint into your filter.
If you want some bypass clean air from above just provide an opening with filter insert.
And if you want fumes sucked away from you (and yr model) put the filter/carbon filter in the rear, either vertically or horizontally only in the rear half of your booth.....
Rolf
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Post by merlin on Feb 18, 2008 15:47:07 GMT
i did think of a filter to the rear rolf , but changed because most booths operate a downdraft system which pulls the paint to the model rather than away . i may add a rear exhaust too TBH simpoly because when doing say primer the paint may be a little heavier , so the added exhaust will help here . as for the overheads the fans are not mounted directly above the unit thats just the inlet . what my plan is , is to mount the fans at the end of a duct so they pull air in but when it exits at the other end its a more gentle breeze shall we say what im trying to do here basically is push the fumes toward the exhaust as much as possible . i,ll take your thoughts onbaord though and i might add the overheads and the rear exhaust , whats your views on using 120mm computer fans , they are pretty cheap , unlikely to spark and replacing them wouldnt be so hard , i would of course be placing a carbon filter infront of them to reduce paint getting through and thus prolong the life
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Post by merlin on Feb 18, 2008 16:05:35 GMT
do you mean like this rolf
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Post by The Hooded Claw on Feb 18, 2008 16:11:10 GMT
How much do you think that will cost?
How big is the footprint?
H
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Post by merlin on Feb 18, 2008 16:15:17 GMT
cost not sure yet , but i,ve obviously got to look at it costing less than a shop bought one . as for size its 36 inches across by 24 inches deep , the height will be set for me so that i can either be stood or sat on say a bar stool to work , but i cant see its total height going over 5 feet tbh
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Post by merlin on Feb 18, 2008 16:20:01 GMT
my plan is to build a full size version from thick cardboard this way i can test air flow of computer fans and how well they exhaust . if it works fine then i,ll build the working version from ply probably . my only concern right now is fans i know i could use bathroom or cooker hood fans , but i,d like to use computer fans simply because of their price and availability , i think they,ll work but i,ll still test em cos i have a dozen of em to hand
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Post by popeye on Feb 18, 2008 16:28:15 GMT
Merlin,
I'm sure you are aware of commercial model airbrush booths with just a vertical filter pack, small extractor fan + top and side shields, available at more or less reasonable prices. If not I can let you have a link.
If you want to build your own - computer fans are too small, use small industrial axial fans - also used in vent units for servers and electronic boxes - fan diameter approx 100 mm. - best as many as 3 to 4 at lower revs instead of one at full power.
The trick in spray booths (big or small) is to move lots of air at low velocity preferably in one direction. Any movement and of course using your airbrush will generate turbulence you want to move away from where you spray.
If you feed fresh air - even from farther away - with pressure into your booth you will only produce less pressure differential and more disturbance in your booth.
If you want to test, fill your bathtub, start draining and after a moment start replenishing at the other end with some coloured water.
Far better than complicating the intake side would be having your exhaust(s) piped away or even piped outside if possible.
(Try to avoid possible recirculation)
interested in the finished subject and your experiences.
Cheers, Rolf
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Post by popeye on Feb 18, 2008 16:38:01 GMT
do you mean like this rolf The exhaust and filter pack can be horizontal / downdraft but move the extractor fans as far away (at least 150 mm) from your filter pack - this also helps getting a smooth aerodynamic movement in your booth. a lot of small computer fans might work, but keep in mind safety issues - more wiring means more risk. Rolf
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Post by merlin on Feb 18, 2008 16:40:27 GMT
these 100mm fans you speak of do you have a link to what your saying , the fans i planned to use where 120mm so i thought this would do . i think what i,ll do is take on board whats said and work from there . so i,ll start with exhaust system and use one of them smoke pellets to test . once this is tested i,ll move to spray paint straight from a can and see what the results are and then i,ll move onto intake , i,ll do as you suggest and just have supply ducts no fans and see if this makes any differance . one thing i cant find is filter media or filter plates so any help here also would be good , seems theres a lot more to this than i thought lol , oh what about the overall design shape etc , do you think this is ok
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Post by popeye on Feb 18, 2008 16:44:51 GMT
after seeing my post - I think I should make my remark clearer:
do not fit the fans into the back or bottom of your both - make a suction box > filter pack - airtight box - fans (accross the filter) to get a straight flow-through.
Rolf
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Post by merlin on Feb 18, 2008 16:49:14 GMT
just doing that now rolf , i get what your saying i think but let me clarify . what you want me to do is remove filters from the booth and have a filter there , then make ductwork go to a seperate fan area lets say a box unit at the end of a 4 foot duct pipe . this way i achieve suction but the fans are away from the fumes/paint overspray does that sound right
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Post by popeye on Feb 18, 2008 17:01:34 GMT
Merlin, just dropped out from login -
I shall get back with some remarks to your and my last post in due time,
let me look for some data first,
Cheers, Rolf
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Post by merlin on Feb 18, 2008 17:03:54 GMT
greatfully appreciated mate ta very much
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Post by popeye on Feb 18, 2008 20:59:50 GMT
Merlin, first - pls have a look at www.mcschueler.de/group_view,Werkzeug,F930E2DBF7D9402A86878EFECBD8082D,de.html Even if in German, you will be able to see what's available and get an idea to surf for same or like units available in GB. I use the same equipment myself and can recommend it. You can also see what I tried to explain - if you want continue. You first need to fashion your box with filter and fans, front will be the filter, in the back you install your fans. Distance between filter and back depending on yr design and construction. More distance means better distributed negative pressure in the filter - i.e. more even airflow through filter mat. 10 centimeters distance will suffice for size you described. Filter mats - look where household items are sold, you can use mats for kitchen extractors. otherwise see yellow pages Fans - 10 to 12 centimeters diameter of fan is the model I was describing. Using three in a row (side by side) would move enough air at medium revs. smaller computer fans - you would probably have to install several more - keep safety in mind - just the wiring for many fans might pose a higher risk. You will also need a grid or stiff steel netting to sandwich the filter mat to prevent the mat from collapsing. As you described - you could start experimenting with just a stiff cardboard box - filter in the front, fan in the back WARNING - don't use EXCEPT for experiments and use just water in yr airbrush ! Your booth should comply with safety regs and should pose no fire hazard !!! Sorry I cannot give better advice where to look for material - am not acquainted enough with the situation in GB - living not just around the corner hope to have been of some help - good luck. Rolf
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