[markha]

OK... Let me start be giving a little background. I have been working on a '32 3-Window for a while. Completely dissembled for paint. This last weekend I took it to a rental paint booth to spray on some etch and high build primer. I thought painting in a booth would be fun. It was a major PITA. It was too much work to get everything there, setup and then back home. OK... now on to my question.

I have two car attached garage that I use as my shop. Not going to use that because of it being attached, but I also have a one car detached that might work perfect as a booth. It is 9' 10" wide by 20' 9" long. The previous person finished this garage with semi gloss paint and it has 4 small long windows. My thought was to use the garage door windows (the little pop out ones at the top of the garage doors) put plywood with fans and filters mounted in it. Then replace one of the windows on the opposite side of the garage with plywood again with fans and filters to create a side draft booth. There are no flame sources in this space. I guess I only have a couple of concerns.

1. Is it wide enough to paint a '32 coupe body? Remember that the coupe is only 43.5" wide at it's widest point.

2. Will I be able to use enough filter material and fans to keep from pissing off my neighbors without breaking the bank?

3. I have read mixed things on here about box fans. Some say they do not generate sparks and are safe to use but then I do not remember who brought up the point about switches etc. Any thoughts on cheap fans that are safe to use?

[66 Restomod]

I used box fans to blow air IN and give it a positive pressure. That way no VOC's were passing through the fans.
I made an outdoor paint booth and did a little write up if you are interested. Might find some helpful information here:
http://chris66dad.tripod.com/id24.html

Good Luck and Be Safe
Ron

[markha]

I saw your write up before from another post. Very nice. Looks like is worked out well for you also.

My plan was to use more fans on the intake than the exhaust to create a slight positive pressure. Your point about using them only on the intake so that fumes are not passing through them is a good one though.

[cboy]

Guys on here have used all sorts of permanent and temporary structures to paint in, so I would guess you can make this work. I think you will have enough space but here are a couple more questions to consider in deciding to use the building. Can you get your air supply to the building (and to your gun)? Does it have really good lighting...or can you import portable lighting. Does it have enough fuse capacity to run really strong lights plus the fans etc.? Can you create a clean environment inside? Are the ceilings finished and able to be cleaned so no dust falls on the fresh paint? Will you be able to keep the temperature at 65 or above?

[Irelands child]

This is (was ) my plastic sheeted booth for painting my '31 which is the same width as a '32. While I didn't paint with the car sitting sideways like that, the booth did allow me total walk around with enough space to kneel plus "swing" the gun. I did the fenders separately as they are big but everything else was painted when the body was done. Approximate booth size was 12'x20'. I would not want it much narrower as it wouldn't allow sufficient space for me in my 'bunny suit', the gun swing, my fresh air hose, my gun air hose. As far as ambient air, IMHO suck in through high mounted filters is normally the best way in a home built booth as it will not bring in dirt as easily. In my case, I probably had no more then 8-10 tiny dust chunks on everything and all but one was in the clear and wet sanded out. The remaining piece - only I can find it and probably got there when I went out of the booth to refill the gun.



The filters - high efficiency furnace from Home Depot/Lowes:

The fan and ducting - an explosion proof 1050cfm from a hot house supplier:



There is a baffle that stands about 4" from the inlet to force air over the top and around the edges instead of directly across the fresh paint.

And one more:



The ceiling and overhead door were also covered but removed a day or so later for better light.
Dave W

[markha]

Great info guys. So to answer some of cboy's questions... This single garage is about 30 feet from my shop. Getting air supply to it will not be a problem. It is completely finished with finished ceilings and the entire thing is painted with semi-gloss paint. It has 2 x 15 amp circuits and one 20 amp circuit in it today. The compressor will be on a circuit in my shop. So I think there will be enough electrical to run the lights and fans. It has some lights today but I will be hanging florescent lights on the walls vertically and then on the ceiling. The temp should not be a problem. I live in So Cal and it rarely drops below 65 during the day.

Irelands child, great info also. You are making me a little nervous about the width of the space I have though. The body is on rollers. I guess I could paint one side and quickly roll it over and do the other side, but it would be a bit of a pain. Any more info on the fan you used?

[Irelands child]

http://www.greenhousemegastore.com/T...ctinfo/FA-VFT/

This is the fan, 12" @ $141 (it went up $22!!!) - no weather hood needed. You do need the $37.50 variable speed control (http://www.greenhousemegastore.com/V.../CT-VFT130144/ )as 1050cfm in a small space is really too much for spraying but 'full throttle' while venting afterwards. I ran mine at maybe 2/3's speed during painting then turned it up to clear the air - though very little overspray with my Iwata gun.

Dave W

[markha]

Irelands child,

This fan setup looks good, but forgive me for saying this... but I can not find anywhere on their web site our on the mfg web site where is says that the fan is explosion proof. Am I missing something?

[Irelands child]

Originally Posted by markha

Irelands child,

This fan setup looks good, but forgive me for saying this... but I can not find anywhere on their web site our on the mfg web site where is says that the fan is explosion proof. Am I missing something?

I probably should call it explosion resistant rather then proof as it is a TEFC motor (Totally Enclosed Fan Cooled) which is many steps better then the "standard" open cooled fans (Chinese box fans from WalMart?) - which a lot of folks doing home/amateur paint jobs tend to use stuck in their shop window.

Dave W

[markha]

Got it. Thanks. Still looks like a good deal.

[FreeRider]

Originally Posted by Irelands child

I probably should call it explosion resistant rather then proof as it is a TEFC motor (Totally Enclosed Fan Cooled) which is many steps better then the "standard" open cooled fans (Chinese box fans from WalMart?) - which a lot of folks doing home/amateur paint jobs tend to use stuck in their shop window.
Dave W

__________________________________________________ ________________

I used to use a 4 car pole building that had a stone floor & 3 of the bays had stuff in it, yes I'm a professional bodyman that did overal paint jobs cheap at home(no buffing). I put one of those Chinese box fans at the bottom of the garage door & enclosed the top & bottom with cardboard, lightly wet the stone floor, wipe the car down & spray.
I'd go outside for a cigarette break between coats & I turned out better paint jobs then Macco or Earl Scheib.

[001mustang]

Why worry about explosion proof fans if the lights are not explosion proof. Let the fans draw fresh air thru fans and push fumes out of non-fanned over-spray filters to minimize explosion hazard. Do not let paint fumes get sucked thru fan. Positive pressure booths blows dust out of cracks not into booth. Use the good sense to stop spraying if your whole booth is filling up with flamable paint mist.

Fans: I use 8 (4 fans two deep) 20"x20" cheap ($5.00 winter closeout) window box fans rated at 2000scfm each (0 dP free flow). This gives you 8000 SCFM (0 dP free flow). The fans produce adequate flow in spite of the filter pressure drop. Fans are exposed to fresh air not paint fumes. Much better to have 4 cheap fans than one good fan, to minimize air velocity concentrations and to better distribute air flow. Of course, 8 window fans operated in parallel would be a dream come true!

Filters: I use paint booth over-spray filters for exhaust windows, and approx 10 micron paint booth sticky filters down stream of fans. The 20" x 20" filters are dirt cheap on e-bay and they work spectacularly.

Plenum: I built 20x20 plywood sided boxes to serve as plenum's and to mount the 20x20 sticky filters. I mount two 20x20 filters per 20x20 plenum box. The more filters/plenum the higher the flow. Stategic placement of filters in plenum will assure a better air flow pattern.

Fresh air intake: I cut 20x20 holes in ceiling and mounted fans in attic blowing air downward. I built an intake plenum in the attic and removed the soffit to serve as an air intake.

Exhaust: I cut 20x20 holes in wall as near to the floor as possible. I install cheap e-bay over-spray filters in exhaust ports.

Air supply: run air supply line downhill toward compressor so condensed water goes away from paint gun. Desiccant filters are overkill providing it is not a wet day and your compressor and lines are designed properly.

Lighting: I installed 16 4' 4 bulb (free, T12 throwaways) light fixtures . I thought the light would be awesome but I found I must bring in portable lighting to properly see paint at different angles. Use clear lenses on your florescent lights (as I say not as I did) so you can see bulb reflection in paint to verify body is straight.

Dust Control: After sanding, blow booth out with leaf blower and rinse booth with water where possible. Put water in a pump-up sprayer and mist walls and WET floor before final coats. Ground car to minimize dust attraction. Start fans several minutes pre final coats and dont turn off fans till all painting is done for the day (fan startup may kick up dust).

Both width: If your booth is too narrow then buy the cheap dollies that go under your car wheels so you can push car side to side. In your case, you have about 3ft per side in tightest area so I would say you are good to go on your 32 coupe.

DIY Supplied Air respirator: Buy two second hand nebulizers (run in parallel to maximize flow) and 1/4-3/8" clear tubing to pump fresh air into your respirator.

Entire spray booth was very cheap since I used leftover paint, wood, thrown out lights (buisiness upgraded to new T8 "green" lol bulbs), bought window fans in fall clearance...

[bobjob]

sounds like you should be fine ...as far as the booth goes......neighbors,,,i see your in corona area..hopefully not in a tract home with with dues and a lot of rules ,, if not,, you should be fine....

[markha]

wow... all great information. Thank you everyone. The box fan is an interesting and temping solution. The cheapest I can find box fans are about $15 each. So I could get 9 of them for the cost of the other true ventilation fan mentioned. The CFM rating on the standard box fans is 2000 - 2500 at 0 pressure. I am curious how this performance really compairs to a true ventalation fan like the one recommended once filters are installed.

Does anyone know of any fan performance tests that have ever been done.

[001mustang]

A "true" ventilation fan must have a large plenum to distribute the flow.
If you run one high velocity fan then you will have a concentrated zone of high velocity air and most of the paint booth will have near zero air flow.

The 2000-2500scfm/fan rating will be reduced with the filters but with the correct setup you will have significant air flow.

Ways to maximize airflow using 20x20 window fans:

1. use two of more 20x20 filters (in parallel) downstream of each fan to minimize filter pressure drop.
2. if necessary, you can run fans stacked in series to increase fan power to overcome filter pressure drop.

For a one car sized paint booth, four 20x20 fan ducts produces decent flow (good enough for me).
I guesstimate eight 20x20 fan ducts could produce flow in excess of 10,000 scfm through the filter system.
I did not run dP calculations; I based my comments on real world data.