Paint booth

[trapper]

Hello all, this is probably going to sound like a stupid question but here goes. Has anyone used the exhaust fan above your stove for a makeshift paint booth? Any help would be appreciated.

[Fat Brian]

I don't think that fan would be ok. If the motor is in the air stream it needs to be intrinsically safe because paint fumes are usually flammable. You can use a squirrel-cage fan because the motor is separated from the air being moved. I've also seen recently someone using a Shop-Vac. The motor is out of the air stream so it's safe, you just need one where the exhaust side allows you to connect a tube that you can vent safely. 

[peteski]

56 minutes ago, Fat Brian said:

I've also seen recently someone using a Shop-Vac. The motor is out of the air stream so it's safe, you just need one where the exhaust side allows you to connect a tube that you can vent safely. 

That is not true at all.  Some of the air stream in vacuum cleaners is actually passed through the motor for cooling it.  Plus, making it even more dangerous, vacuum cleaner motors are motors with brushes which spark while running.  Never use any vacuum cleaner for extraction of flammable fumes!!  BAD IDEA!

The kitchen or bathroom exhaust fan, while not quite appropriate, would be safer than a vacuum cleaner motor because exhaust fans use shaded-pole AC induction motors which do not have sparking brushes.

[Sandboarder]

4 hours ago, peteski said:

Never use any vacuum cleaner for extraction of flammable fumes!!  BAD IDEA!

It’s funny how I just read this thread. Opened up YouTube and saw this video. I think I’m being watched.

 

 

Edited May 3, 2022 by Sandboarder

[peteski]

55 minutes ago, Sandboarder said:

It’s funny how I just read this thread. Opened up YouTube and saw this video. I think I’m being watched.

LOL, of course you are.  All our internet activity is being tracked by AI.

[Fat Brian]

10 hours ago, peteski said:

That is not true at all.  Some of the air stream in vacuum cleaners is actually passed through the motor for cooling it.  Plus, making it even more dangerous, vacuum cleaner motors are motors with brushes which spark while running.  Never use any vacuum cleaner for extraction of flammable fumes!!  BAD IDEA!

The kitchen or bathroom exhaust fan, while not quite appropriate, would be safer than a vacuum cleaner motor because exhaust fans use shaded-pole AC induction motors which do not have sparking brushes.

Shop-Vacs are wet/dry, they can't pass potentially water containing air through the electric motor. The motor does have a separate fan for cooling but it's not using air from the vacuum side for that. Here's a picture of a Shop-Vac motor, you can see the motor cooling fan on top and the on the bottom is the enclosed vacuum impeller. 

[cheyenne93]

I had built one several years ago using  a 30'' range hood mounted on top of a steel cabinet, so it also served as paint storage cabinet. Ducted outside with a 4'' dryer hose. Worked well. Sorry no pics. Yes most range hood are brushless motors. 

[espo]

Using a shop vac is something I never have considered. Maybe I should say I just never thought of it. 

15 hours ago, trapper said:

Hello all, this is probably going to sound like a stupid question but here goes. Has anyone used the exhaust fan above your stove for a makeshift paint booth? Any help would be appreciated.

Now what I have done is to use the exhaust fan from a bathroom to sort of boost the air flow. We just downsized this year, and the daylight style basement had a bathroom with an exhaust fan that exited at ground level to the outside of the house. The exhaust fan tubing is exposed in an unfinished area on its route to the outside. I partially finished the storage area and added a work bench where I can do spray painting and such. I placed my spray booth on the bench and ran the exhaust tube up to the bathroom exhaust tube and joined them with some Home Depot type metal fittings.  The bathroom exhaust has a little more volume and is a slightly larger diameter than the paint booth exhaust. I use the bathroom exhaust fan plus the fan in the spray booth when painting. My thought is that the larger volume of the bathroom fan helps pull the exhaust from the spray booth when in use. So far I have had zero odor issues and no sign of paint residue so it seems to be working even if it is a little Rube Goldburg of a setup.  

[peteski]

13 hours ago, Fat Brian said:

Shop-Vacs are wet/dry, they can't pass potentially water containing air through the electric motor. The motor does have a separate fan for cooling but it's not using air from the vacuum side for that. Here's a picture of a Shop-Vac motor, you can see the motor cooling fan on top and the on the bottom is the enclosed vacuum impeller. 

Ok, fair enough.  Still, I would be leery of using the brushed motors (which always generate sparks), in a exhaust system for flammable gasses, unless the motor was totally sealed off.  Shaded pole AC induction motors are safer (and lower rpms much quieter than any shop vac).

Edited May 4, 2022 by peteski

[ksnow]

Here's the spray "booth" I just built in my shop, in a basement. I used a marine bilge blower. Designed to move gasoline and other fuel vapors. Runs off a 12v DC power supply. The blower cost about 35 bucks, same with the power supply. A little wiring and ducting. No smell at all in the shop. Not noisy enough to bother the wife upstairs.

[bobthehobbyguy]

The one thing that has to be considered is the potential for fire and explosion if the improper fan type is used. You may get away with using an improper fan but it only takes one time when the air fuel mixture is right and you're in trouble if there is a spark.

If I was building a paint both I'd use the bilge pump as used in the previous post. 

[BuilderX]

I did that home made paint booth for a while (used computer fans and a plastic tub). Then I broke down and bought the the mini 24" booth from Pace.

[Fat Brian]

2 hours ago, peteski said:

Ok, fair enough.  Still, I would be leery of using the brushed motors (which always generate sparks), in a exhaust system for flammable gasses, unless the motor was totally sealed off.  Shaded pole AC induction motors are safer (and lower rpms much quieter than any shop vac).

It's not the way I would or am planning on doing it but after looking at it there are worse ways.