Going to start on my booth,

J

jtfx6552

Member
I think I read every post in this forum. Been scouring crags list for a "real" fan or fans with no luck. Seems to be a weird break where you can buy box fans for just about nothing, while real fans are $100s if not a $1000 dollars.

Pretty clear to me that real HP is needed and box fans don't have that. I have seen some flow rating on box fans and it's in the 2000 to 3000 cu. ft/min range, but based on the low cost and of course low HP, that must be against no static pressure and I'm sure with any pressure against them the flow drops dramatically.

I have hanging around my place 5 box fans. My plan is to make a plastic sheet wall to cut my garage in two, line the 5 box fans on this plastic wall blowing in through filters, and leave the 3 windows open on the far wall. I'm thinking that 5 of these fans on high should move enough air through the filters and out the windows. Not as much as a real booth, but hopefully enough that the fog doesn't lay back on the top.

Is the consensus that that might work? Or do I need even more box fans, or do I punt and keep scouring craig's list?

Edit: And how sophisticated do I need to get on the filters? Do I get really boot filters from the local jobber, or would something like this work? http://www.homedepot.com/p/Rheem-20...old-Pleated-Air-Filter-64100-012024/203140810
 
Here's some information that should help. Also, tractor supply places generally sell high CFM fans. These will need to be pushing fresh air into the booth since the motors are not explosion proof. You should have your intake filter bank sized according to the air mass you want to move and the exhaust filter bank sized equal to or just under the intake filter bank size.

Paint Booth Airflow Calculations

Scenario #1 - Air moving from ceiling at back of booth to the exhaust filters at far end of booth.
Based on these assumptions:
Surface area (ft2) = 4.4m (wide) x 2.2 m (high) x 10.76 (m2/ft2)
= 102.4 ft2
Air velocity = 102.4 ft2 x 100 ft/min

= 10,240 ft3/min
Scenario #2: Air entering at ceiling and moving downward toward the filters immediately above the floor along the sides of the booth.
Based on these assumptions:
Surface area (ft2) = 6.6m (long) x 4.4m (wide) x 10.76 (m2/ft2)
= 312.5 ft2
Air velocity = 312.5 ft2 x 50 ft/min

= 15,625 ft3/min
If you want uniform air distribution throughout the booth you should size the air intake filters accordingly. If you make the filter section too small, you can expect turbulence in the booth and this will cause paint overspray to settle on the walls, ceiling, lamps, etc. In addition, turbulence lowers transfer efficiency.
 
I have used filter paper intended for a industrial oil&water filter with great success. ( I think it was rated at 20 micron )

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I put covered the full opening of a 16w x 7h garage door opening . At the other end of the room I had 2 half horse wall fans with shutters mounted in a piece of plywood and hung on hinges in place of a screen door on the far wall. I salvaged the fans from a shower room remodel at work.

Check around where you live if you are interested in the flat bed filter media. It is a very common type filter anywhere they use coolant in a manufacturing process. We tossed out the last inch or so on a roll and put in a new roll so it wouldnt run out while unattended.

btw, those things are a real mess to work on after they have been in service for a while and are all slimey and grimey , lol.
 
http://m.ebay.com/itm/291142543291?_mwBanner=1

I bought this fan. It is alum. and is infinitely variable speed, from a creepie crawl to full speed. It also has a sealed motor. While it is not rated explosion proof unless you are going to spray on a daily basis I don't think you have anything to worry about.
I tried the ones from Tractor Supply and if used at full speed it will work great but full speed is too much. I put a 5a (I believe) ceiling fan speed control switch (the seller sells them too) from a Handyman Hardware store. That will let you tailor the exhaust pull to exactly what you need and if just working and need to cool the shop down turn up to full speed and you get a nice breeze for shure.
 
Also if you use a fan on a veri. speed switch it will go into thermo overload and shut off until it cools. That's what happened with the one from Tractor supply. This one has been a real nice addition to the home shop when painting and just working.
 
DATEC;n74891 said:
http://m.ebay.com/itm/291142543291?_mwBanner=1

I bought this fan. It is alum. and is infinitely variable speed, from a creepie crawl to full speed. It also has a sealed motor. While it is not rated explosion proof unless you are going to spray on a daily basis I don't think you have anything to worry about.
I tried the ones from Tractor Supply and if used at full speed it will work great but full speed is too much. I put a 5a (I believe) ceiling fan speed control switch (the seller sells them too) from a Handyman Hardware store. That will let you tailor the exhaust pull to exactly what you need and if just working and need to cool the shop down turn up to full speed and you get a nice breeze for shure.
Click to expand...

That is very similiar to my 2 salvaged fans. Mine were 20" if I remember correctly. (lost them in a garage fire - from sharpening a lawn mover blade)
 
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