have been looking into getting a filter box for our spray booth
the dealer quoted me several models, varying in width and height, but the depth on all of them is 4ft, this seems kind of crazy to take 4ft of depth out of the entire 20 ft spray booth.

while the lacquer is drying I put all the racks in the booth and turn up the heat
often quite a few big odd ball pieces etc. etc., at that moment I want as much room as possible

has anyone ever build or bought a filter box with less depth? lets say 16" deep for example?
does that affect the filter or fan performance?
can't seem to get an answer out of the salesman on whether a shallow filter box is available, getting tired of bugging uninterested sales people.

if anyone has some good advice on this, don't hesitate to post it here.

here is ur answer, the reason filter boxes are not one or two feet is the velocity at the face of the spraybooth, especially filters,.. the depth creates a "quiet zone" for the velocity to slow down. if you didnt have that face velocity at the filters would a create so much fpm that the filters would load up very quickly and ur transfer effeciency would drop dramatically,. building them please not out of wood , is not hard. if you have a friend who is a sheet metal contractor might be able to help you. also, remote mount the fan on ur roof top.then put a disconnect on it. a. fan noise less and a smoother airflow. also get a vfd then you can adjust the fan speed. if you need more info just let me know, have sold booths and spray eqpt for almost 40 yrs, damm i m old.....

good luck , herb j

That's great info!!
What would be the downside to building the filter bank out of wood?

Putting the fan on the roof doesn't work in my shop because the spray booth is under a mezzanine, which has an office above it lol

But your point is to mount the fan outside the building, and run ducting to to the filterbank?

Is there a reason that all booths have the fan mounted on the top rather than the back wall? Given that my spray booth is 10'-6" high, I'm going to run out of room quickly

if i were to put a 30" dia. elbow at the top of the filterbank
I'm not sure how big those elbows are, but I'm guessing about 5ft tall, which leaves me with only 5' high filterbank(probably need some clearance by the ceiling to mount the fan properly)

first off how did you determine you need a 30''fan?

ut your point is to mount the fan outside the building, and run ducting to to the filterbank?
that works, what size duct and how long of a ductrun

how are you going to terminate the end of the duct. i would hope a gravity style damper

why on earth build a booth out of wood. and don't tell me it is waterbased material

on standard booths the top exhaust panel it very typically interchangable with the back wall of the spray booth. whether you mount the fan depends on ur building, how u r going to exhaust the fan etc.

the advantage of putting the booth outside is noise and effectivness. downside, weathertite disconnect and wiring cost, freeze proof sprinkler head

good luck

herb j

i forgot, i get u want to save room, space is always at a premium , fwiw, just check out any standard not the brand name three sided booth.

they range if made properly from 30'' or more. there is a multiple reasons. i think i listed them above. especially if one or two man shops economics and space are front and center. from there you have to make decisions based on ur circumstances. i am only giving u as much as i can pro's and con's, i don't want u to get the feeling i am bustings b...z.

good luck herbj

sorry one other thing, many times i have seen small shops go with explosion proof motors, typically by the time you get filled wiring and xp switches, etc. unless ur fire marshall or inspector wants it, u might choose to go with a tefc motor and remote mount it. also depends if u r going with single or three phase. i have seem some shops go with a vfd to buy a threephase motor and double the size of the vfd. all this depends on ur situation, electrical needs, panel, inspectors etc. also take into account ur neighbors or business's located near you, are they going to bitch about the fumes. all this stuff among many others is that part of ur decision making process. a lot of things and info need to be gathered as you move forward, i don't have any idea where u live, codes, inspectors, etc and not asking u to divulge . if u live out in the middle of 90 acres or in the city

Who puts a spray booth in a building that has offices above it? Am I the crazy one?

the fan size I determined from the info I got from a dealer that recommended that I get a 30-34" fan 5hp, 12000 cfm
thinking to do a 12-16ft filter wall x 6 or 7 ft high
would you recommend a different size fan?

my original idea was to put the fan in the building, but since you pointed out the noise reduction, I figured go out of the back of the filter bank through the wall, with a round duct, and then mount the fan.

would it matter whether the fan is facing forward or up?
is there a need for a damper?
if I'm facing it up, then I'll obviously need a rain cap

in regards to building the filter bank out of wood, why not? what's the advantage in using metal?
no I'm not spraying water based

i was thinking to use an explosion proof motor, 3phase, I don't need to worry about all the codes, I'm out in the sticks(gladly)

currently have a 5000 cfm fan with a filterbox in front that's about 20-24" deep, its about 35 sqft of filters
probably not enough eh?

if I go with a bigger fan I probably will put get a VFD put on there, i'm a bit concerned that i'm going to hate the 12000 cfm

@JeffA
I'm a one man cabinet shop
nobody working in the office when I'm spraying, and not until all the fumes are out of the shop
but what I'm trying to achieve here is to get rid of the fumes + overspray quicker and better than the setup I have now.

wood burns metal doesn't

i know about saving money but no way in hell would i building a booth out of wood..

10 wide 6 high even at 125 is no were near 12k cfm

dump that dealer

if u are worried about safety, build it out of something other than would

why an xp motor? why not tefc,?
also it isn't xp if you don't have a xp filled and sealed wiring, an xp motor starter, i could go on.... that will cost you a fortune for an electrician and parts to make it a true xp system

if you don't have side walls and just an exhaust chamber, the codes if you are concerned about them no disrespect cause the entire area for electrical code restrictions. , i.e. an xp area., see nfpa chapter 33 fwiw side walls improve airflow directly over the parts you are spraying, without side walls, air =enters from side tops etc. side walls direct the air over the parts u r spraying, it is sometimes called laminar air flow. the air enters from ur butt side and comes across. it also improves transfer effeciency because typicall air and fluid ;move direectly over the part and does not get whipped around from side currents

i do truly get a one man shop operations it is tuff as hell, just one mans opinion and certainly far from an expert, just trying to give you some general info, ymmv, just opinions , no i am not a paid consultant etc, god forbid you build a booth out of wood, honestly, and solvent or even water based products, make every damm effort to make sure you have everything grounded to the max, use a meter to verify.

best of luck

herb j

sorry one other point, as far as filter area goes, look up an good mfg, look for the of the booth u r building, in the spec it will say home many , typically 20-20 filters,, multiply 2.77 that is sq ft of that filter times, x, the number of filters in the exhaust chamber, and their u have it the recommended filter area whether 20 2o 20 25 or roll media the sq ft that booth mfg recommend