Booth air intake

the reality in my shop is that the fan is so big it creates a negative pressure in the whole building. this is why i cant burn the wood stove with it on, it will reverse the chimney draft. i initially set it up for welding fumes, and it works very well for that. of course it expels paint fumes too..........i highly suspect it is the reason i get so many nibs also. too much air movement. in any case, its what i have to work with. if i was to build a real booth, or as close as i could come, i can now see a benefit to a low exhaust.
When I run my booth fan I open the shop man door. You don’t want to create negative pressure in your whole shop imo.
 
When I run my booth fan I open the shop man door. You don’t want to create negative pressure in your whole shop imo.
yes i do that some times...........it does drastically increase flow though, like wind blowing through. its really too much fan but it works good to cool the shop on hot days. obviously i cant do that when heating, it would cool off in minutes.
i got so i dont run it much if just shooting a panel or like shooting a frame section. i just shoot it, turn the fan a minute or two to clear the air and back off.
i may consider a smaller fan in future. not getting rid of the big one though, just to have options.
 
yes i do that some times...........it does drastically increase flow though, like wind blowing through. its really too much fan but it works good to cool the shop on hot days. obviously i cant do that when heating, it would cool off in minutes.
i got so i dont run it much if just shooting a panel or like shooting a frame section. i just shoot it, turn the fan a minute or two to clear the air and back off.
i may consider a smaller fan in future. not getting rid of the big one though, just to have options.
You can put a variable speed switch on some of the fans.
 
had a usi spray booth move a lot of air we got cleaner jobs when filters were used seem to slow air movement
 
Filters do cause some restriction, but multiple filters also offer more square inch delivery than what comes out of the intake fan without filters, or only one filter.
 
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the reality in my shop is that the fan is so big it creates a negative pressure in the whole building. this is why i cant burn the wood stove with it on, it will reverse the chimney draft. i initially set it up for welding fumes, and it works very well for that. of course it expels paint fumes too..........i highly suspect it is the reason i get so many nibs also. too much air movement. in any case, its what i have to work with. if i was to build a real booth, or as close as i could come, i can now see a benefit to a low exhaust.
What I wrote above was in relation to a fan mounted in the ductwork. It really makes no difference IMO where it's mounted in the ducting. Most of the booths I have used over the years usually place it behind the exhaust manifold (obviously) and about 6 feet or more off the ground. I have seen booths with fans right near the top of the stack on the roof as well. Or mounted in the stack at the top of the booth roof, then ducting through the ceiling.

Air flow, yes high (intake area) to low (exhaust manifold/outlet) but that doesn't mean the exhaust fan has to be mounted low (in the context of a ducted system). Most (all?) booth fans are tubeaxial anyway so they have to be mounted in the ductwork. Now if you are using something other than a tubeaxial fan I have no clue. Especially If they are underpowered it probably would help mounting them as close to your exhaust filters as you can. I have no experience in that area. I only really know what proper spray booths do.
 
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had a usi spray booth move a lot of air we got cleaner jobs when filters were used seem to slow air movement
Last Shop I was at when they hired me, they were having big issues with dirty jobs. Paint booth was running wide open. Pulling really hard. I installed a VFD (variable frequency drive) to the booth fan, and that made it so you could adjust the speed of the fan. Ended up running it at about 32-35%. Night and day difference in the amount of trash in jobs. And the intake filters lasted longer as well.
 
intake filters:



I have a semi-downdraft booth, intake filters at the top and exhaust at the floor. Helps to persuade any dust particles that get past the tacky filters towards the floor.
 
i have used all variations of intake filters and have settled on the better R1 type. they are usually white with a fine fabric on the outlet side which acts as a final filter. the difference between those and the green and blue tacky ones is night and day. they are more expensive however but the dust they filter out is way better. they do restrict more airflow and clog faster though but that is because they are filtering the air better. i highly recommend you go with those. i cant even use the green and blue ones. the crap that gets through those is crazy. pollen and shop dust goes right through.

my booth is crossflow and like chris was saying, its just a wall of exhaust filters with the fan about 6' above the floor. as the booth gets used the filters closest to the floor will clog first then you will gradually see them get dirtier higher and higher as they clog. that tells you right there where they are most effective.

intake filters are in the doors at the other end and start at about 1.5' off the floor and go to the top of the door. there are 16 of them. 8 in each door. i wish there were more on the intake side. there is a bit of neg psi in the booth with a 5hp 34" fan using the r1 filters. if you could do 20-24- 20" filters that would be good. keep in mind your fan size as well. a proper booth will move air in a column at 75-125 feet per min.

 
i have used all variations of intake filters and have settled on the better R1 type. they are usually white with a fine fabric on the outlet side which acts as a final filter. the difference between those and the green and blue tacky ones is night and day. they are more expensive however but the dust they filter out is way better. they do restrict more airflow and clog faster though but that is because they are filtering the air better. i highly recommend you go with those. i cant even use the green and blue ones. the crap that gets through those is crazy. pollen and shop dust goes right through.

my booth is crossflow and like chris was saying, its just a wall of exhaust filters with the fan about 6' above the floor. as the booth gets used the filters closest to the floor will clog first then you will gradually see them get dirtier higher and higher as they clog. that tells you right there where they are most effective.

intake filters are in the doors at the other end and start at about 1.5' off the floor and go to the top of the door. there are 16 of them. 8 in each door. i wish there were more on the intake side. there is a bit of neg psi in the booth with a 5hp 34" fan using the r1 filters. if you could do 20-24- 20" filters that would be good. keep in mind your fan size as well. a proper booth will move air in a column at 75-125 feet per min.

Thanks Jim! My booth has two passes of intake filters. I am going to try these on the second pass filters.
 
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My jobber has Viscon-air and the 20X20 intake sticky are $211 a box of 20. I am looking on line now to see what is out there.
 
My jobber has Viscon-air and the 20X20 intake sticky are $211 a box of 20. I am looking on line now to see what is out there.
that link i posted above has really good pricing. you'll get the better filters for the same price as the tacky ones locally
 
I really like the R1 intake filters, have you checked out the exhaust filters to find the best type also? My neighbors are close by.
Look for exhaust filters that meet the EPA requirement which is 98% efficiency IIRC. That doesn't mean though that your neighbors won't smell something. The 98% refers to capturing solids. The higher your exhaust stack exit is the less your neighbors will smell. Much like with a conventional chimney. You could rig up something with activated charcoal filters but using and replacing them would be expensive.
 
Look for exhaust filters that meet the EPA requirement which is 98% efficiency IIRC. That doesn't mean though that your neighbors won't smell something. The 98% refers to capturing solids. The higher your exhaust stack exit is the less your neighbors will smell. Much like with a conventional chimney. You could rig up something with activated charcoal filters but using and replacing them would be expensive.
I'm trying to find something productive for charcoal for filtering my shop air and even that I am finding to be very expensive.
 
yeah i just use regular cheap fiberglass paint arrestor pads. nothing special. your really pissing in the wind to try and remove the fumes. get a high powered fan and blow that $hit straight up and paint when the wind is blowing away from the neighbors. thats about all i can recommend
 
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