my garage is 24x24. I have 2 10x10 double doored swingout barn doors on one side. I have 2 4x4 windows on each side wall, with one side wall also w/man door. nothing on back wall. I've thought of using window screen over the big doors(keep bugs out w/door open),filtered box fans pulling air in from the side windows, and putting 10 feet on each side of the truck of galvanized ductwork laying on the floor with one open end up against the door screen, and the other end with a 90 degree elbow facing up with filtered box fans laying on the open face aiming down into them. my goal is to pull the overspray and fumes down, as opposed to across the body of the truck. does this sound like it would work? the spraygun is hvlp. sorry for the long post. I've also posted this in the bodywork forum.

 

I've been considering the same sort of thing. My garage is different, but similar. Having a little hard time visualizing your proposed setup, but I think you'll need to relocate the fans. They need to pull the air into the duct. If you try to force feed the ducts, the fan will just produce a positive pressure in them and reject the rest. I don't think box fans are sealed enough to create that much pressure without 'leaking out.' I also think that with 200sf of opening is too much. The air will be going straight from the door openings to the fan/ducts with not much actual down draft (mostly horizontal draft).

My idea was to take my fan (much bigger than a box fan), and mount it on the outside of the garage door so I can take it on and off. Make one of the panels in the door right by the fan removable. Then take 20' of maybe 24x6 rectangular duct work and run it under the vehicle. The duct would have holes along the sides for intake.

 

thanks for the reply. I have a squirrel cage fan I could put on the other end of the duct work and put holes in the duct along the length of it, like you had mentioned. I thought about hanging plastic down in front of the doorways also to keep the outward air from being too much. My drawback is my doors don't go up like a normal door. they open out like barn doors, which means I can't block it very easily. each door is 5x10, with 2 pairs on the front wall.

 

In all reality here,what you both are describing is Ilegal and dangerous.
Not that I haven't done simaliar things. trying to make a downdraft booth is futile to say the least.
But use explosion proof fans. heat sparks and static cause more explosions than people think.
The easy way to keep dust down is to wash your floor area ,then wet the floor prior to painting and keep all dust collecting items out of the area.
Be careful of your neighbors if they start smelling fumes it could be the begining of the end.
Just becareful.
Sorry to step on anyones toes here but!
Painting is fun ,but can be dangerous.
Rich

 

Rich, that was very eloquently put. I've never been told I was a dumb a_ _ so nicely. Thank you, and I don't disagree. I was thinking the same two major concerns, which is at least partially why I have'nt done it - yet.

Let me side track for a moment to prove my intellegence. Once I was painting in the garage (which I do alot) one time in cold weather, got the place nice and toasty with the furnace (can you see where this is going?). I usually unplug the furnace until after the fumes have dissipated but forgot this time. It got pretty cloudy in there - and the furnace started. Saw my life flash before my eyes, and was hoping I've been a nice enough person, so that my family wouldn't be alone at a funeral. It didn't blow, and I feel lucky.

I've also painted my neighbors evergreens, um... red. The trees are fine.

The reason I was still thinking of doing this is because with the change of air that we would be talking about (with my monster fan), the fumes would be far less than that very lucky night. Also, with the fan outside, it might not kill me if it does blow (don't say it - I know).

Illegal, probably, but it's not like either of us is doing this commercially and to me it's no worse for the environment than without a ventilation system (if environmental issues is what's illegal).

So to try to keep this post from getting much longer - I agree with you, and don't mean to be argumentative. Please elaborate on "trying to make a downdraft booth is futile to say the least."

 

I was just throwing ideas around. Winter is here, and I'm bored. My shop is being built this summer, and I'm using the old garage in the meantime. After reading 26 pages of bodywork forums, I thought I'd post on the downdraft process, as opposed to the crossdraft process everyone talked about.

I should also mention that my goal was for visibility purposes, not fumes. I have a makeup air mask. (autobodytoolmart)

 

No problems guys
Just be careful ,wouldn't want anyone to get hurt!
I've painted in downdraft booths they are nice when setup correctly (proper rate of air exchange) . But if not they are a pita
Even when just painting in your garage try to use explosion proof fans and prper judgement.
Rich

 

One question i have is are you pulling all the air down or is there something to blow the air down. For a down draft booth to work well you need to blow in and suck out. The down draft booth we have at work has to fans. One fan blows the air in from the celing downward. The second is one in the floor that sucks the air out. One idea i have is to put a fan outside that blows through the duct work one the celing. Place filters over the holes to catch any dust that comes in. In the bottom put filters in the opening to filter the overspray as it goes out. Thats how most body shops with a down draft booth have.