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Discussion Starter · #1 · (Edited)
OK I've done some research and can't seem to find out how to make a exhaust system for a box truck. Here's the idea..
Put one of those exhaust fans that don't explode with fumes inside the box truck to cause a "pull" or negative pressure inside the box. Then somehow filter the air going out so that it is "clean"....and might even pass EPA guidelines.
I am wondering if it is as easy as putting an approved filter through all exiting air. Any ideas?
Oh yeah, almost forgot..
Any ideas on how much negative pressure I would need to pull out exhaust from that box? Or which exhaust fan? I may even cut it in half and make a smaller room inside box just for spraying. Thanks!
 

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Discussion Starter · #3 ·
Thanks for the reply..
Not the same.....I want a pro install, like I'll be using a $600 fan. It will be a permanent fixture. I actually did do a search! Thanks again....
 

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Brian Martin,Freelance adviser
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I don't have the answers for what fan to use or anything like that but you better do a LOT of home work before you spend any money on this. I find it hard to believe that any such booth could be made that you could drive around and paint stuff in there. What do you plan to paint that is small enough to put in there?

I had this idea many years ago actually. I saw a need (don't know if it REALLY exists) for painting filing cabinets when offices do remodels. I saw a company send out a whole room full of cabinets for painting and I though hey, maybe I could go and do it at the site. Anyway, so I have thought about this before. But today with what I know after working with bodyshops and such, I can't imagine it could be done. First off the "EPA" doesn't have a darn thing to do with spray booths, that is a federal agency and WAY bigger than some guy with a spray booth. We are talking city and county agency's like the city fire dept (they usually handle stuff like this as it's a FIRE that they are concerned with) and around here the "Bay area air quality control" as it's commonly called, or BAAQMD - Home

I am just not sure you can do anything. Do lots of homework!

Brian
 

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Discussion Starter · #5 ·
Brian,
I was hoping that you'd reply...
I have actually seen it done. In two different applications. Basically there was a smaller room built in a trailer. The entry door had a filter on the window part and used as the clean air intake. Then a cabinet in the room with an exhaust fan pushing air out and filters before fan. It worked pretty good....
I guess what I am wondering is it really that easy? Create an air flow and filter it with paint filters?
 

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Particulates would be trapped by the filters. What needs researching is requirements to filter fumes. This used to be done with water, now I don't know if that is effective or acceptable.
 

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The fumes are what you need to be concerned with as previously stated; not to mention OSHA might get a little randy over the whole entrance and egress from a confined area thing. Also, you better make durn sure that your particulate filter works 100% every time. Otherwise, when the wind blows the wrong way and the audi dealership has 40 A4's with green paint specks; you'll going to contemplate 'seppuku'
 

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mobile meth labs were big business here; one blew up outside of Albany NY IIRC.

Now, with pseudo ephedrine so hard to get in quantity; theres a new method to making this poison. Essentially you make a tiny batch in a soda bottle. Pay a few homeless guys to walk around shaking soda bottles and it adds up quick.

But yeah; I think you'd need to really delve into the legalities of it; so your business plan better be REAL sound.

I do know there are 'chip repair' guys who do the PDR and then a little touch up with an airbrush; not sure how they get away with that. Maybe Brian (MartinSR) can shed some light?
 

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Discussion Starter · #10 · (Edited)
Thanks again for replies,
I currently spray outside. I'm a mobile tech. I do small repairs, and am working under the under 3 oz rule. EPA basically says you can spray outside (don't ask me how they came to this conclusion) using under 3 oz of material. That being said, I am currently not using ANY filtration for particulate (being that I shoot outdoors) and so even 50% is better than 0%. Ha ha...
So if 0% of particulate and 0% of fumes are required to be filtered under this rule, I should be in good shape. I will still be shooting under 3 oz in mobile booth. I proly shoulda given a bit more info..
The question: Is this as simple as creating an air flow, then filtering with good filters?
 

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point on positive
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Put a 12 volt radiator in the floor near the door so when your getting in and out (mostly out) your in the vacuum and the dust goes straight out of there instead of hitting what you just painted..

Find a adjustable rv roof vent that you can put a cut to size common $15 booth filter in

Put the roof vent over the fan.. the air current will roll everything down and out..

Don't put the filter at the other end like a cross flow booth the air will roll around and pull everything with surprisingly little air movement..
Add a fan if the box is bigger... start small

Have a switch for the fan on the inside as well as the outside so you can get in without the fan on until you need it..and be able to turn it off from outside without opening the door..

You can do it, hope to see it
 

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Brian Martin,Freelance adviser
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Like I said earlier I can't believe the EPA would give a crap less about what some guy was doing with his touch up gun in Heyburn Idaho. They have much bigger things to worry about. The local agencies, most likely fire dept is the one that will come in and kick your butt.

I don't remember the particulars and to tell you the truth they would likely be changed now anyway. But I had no booth at my little shop and use to keep things pretty small, the rule was something like spraying under 6 square feet was legal something like that. I had an insurance adjuster sic her dad on me who just happened to be the fire chief in town. :rolleyes:

He rolled in and told me I couldn't spray without a booth, I brought up the 6 square foot rule and he brought out his book and let me read a page, it talked about needing the air exchanged every certain period of time, I forget what it was. And I remember looking at him and saying "Come on, that's a booth, it says you don't need one but that is what it's describing" and he just smiled while keeping eye contact with me closed the book with his right hand. :evil:

He knew his daughter was a beach and he didn't give me too hard of a time. But he COULD have. The fire issue is much more an issue than the vapors that escape. We are talking about an explosive box here, that pretty much trumps some thinner evaporating into the air.

And these laws are so confusing even the people who carry around the little rule book don't have a clue. I had a fire inspector tell me I had to have an explosion proof cabinet that held a certain amount of paint (I think it was 10 gallons, but don't remember) I went out and bought this five hundred dollar cabinet only to have the next inspector a year later tell me I didn't need it and the other guy was wrong!

That was 30 years ago and I just recently brought that cabinet home from where I now work. I had sold it to this shop across town when I closed mine never imagining I would be working for him, it's not like I knew him or something. So here I am and the other day they were tossing it out so I grabbed it for my garage. :thumbup:

Anyway, honestly, not many of us can help you with this project because the laws and ordinances in our towns can be completely different than yours.

A booth is simple math, you need a fan that will exchange the air inside of a box in a certain time frame. It is a simple formula of how big that box is and how much cubic feet of air the fan moves. The air intake to that box has to be big enough that the amount of air needed can enter the box.

I worked at a truck painting place with a fan that was about three feet in diameter and sounded like a friggin 400 horse small block when it got cranking! The booth was about 25x25x50 and that fan was moving some air!

A basic old cross draft booth could be pressurized I imagine but generally it is simply sucking the air from the box and you put a hole at the other end of the box with filters for an air intake so you don't suck dirt and small birds into your booth. The air exhaust also has to be filtered so the paint particulates can't leave.

But honestly, you had better do your home work as building this thing and then being told you can't use it would suck.

Brian
 
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