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Building Tips and technical articles. => Paint and finishing => Topic started by: Willie Johnson on August 17, 2011, 08:53:25 AM

Title: Exhaust Fan Type?
Post by: Willie Johnson on August 17, 2011, 08:53:25 AM
I am in the middle of organizing and upgrading my workshop.  I can't get anything done in the previous setup.  I want to do some dope spraying and with fall and winter coming up, I will need to do this inside.  I noticed some of you are using exhaust fans.  I have been pricing explosion proof fans at $500+.  Before I save up and made that investment I thought I would ask what type of fan everyone else was using?

Thanks,

Willie
Title: Re: Exhaust Fan Type?
Post by: Mark Scarborough on August 17, 2011, 09:43:07 AM
Willie,
I have used a squirrel cage fan with reasonable success in the past. You want one that is belt drive preferably, then you can isolate the motor from the airstream of volatile vapors.
I have used standard old box fans, but BUT BUT that puts the motor directly in line with the flow of explosive materials and isnt a good idea.
Title: Re: Exhaust Fan Type?
Post by: Will Hinton on August 17, 2011, 10:25:43 AM
I ran across a full-house attic exhaust fan for fifty bucks years ago that I installed in the wall of my "dirty" shop.  It really does the job.  However, it isn't explosion proof as far as I know.  I mainly use it for dust removal while routing, sawing, etc., but must confess I also use it for painting.  (Fingers crossed!)
I had a furnace fan before, and it worked quite well, and is explosion proof.
Title: Re: Exhaust Fan Type?
Post by: Randy Powell on August 17, 2011, 10:48:12 AM
I use a set of two attic fans mounted in a frame that fits in the window of my shop. I open the door, turn on the fan and air is drawn from the door and out the window. I do have to clean the fans after painting, but it seems to work pretty well.
Title: Re: Exhaust Fan Type?
Post by: Peter Nevai on August 22, 2011, 02:00:16 PM
Just about any brushless AC motor is good. Nothing inside to cause a electrical spark so nothing to go Boom. Make sure it does not use a mechanical start although most use a starting CAP nowadays.
Title: Re: Exhaust Fan Type?
Post by: john e. holliday on August 25, 2011, 05:25:12 PM
I think in my opinion if the paint vapors get dense enough to explode you would not be breathing.   I usually spray outside the shop now.  Before I would set up a box fan pulling the air out of the basement.   The stuff I was painting was between me and the fan.  Get the air circulating before starting to paint. H^^
Title: Re: Exhaust Fan Type?
Post by: Crist Rigotti on August 30, 2011, 02:43:59 PM
I use a fan that has a shaded pole motor on it.
Title: Re: Exhaust Fan Type?
Post by: Steve Helmick on August 30, 2011, 07:04:44 PM
Wouldn't it be safer to have the fan pulling fresh air into the shop, so no fume/spark (or fan cleaning) issues?  ??? Steve
Title: Re: Exhaust Fan Type?
Post by: wwwarbird on August 31, 2011, 09:44:23 PM
 A few years ago, after much searching, I bought an exhaust fan already mounted in a sturdy frame with louvers that open and close automatically with the fans operation. I found it at a Mills Fleet Farm store and it's intended for farm building use. I simply made a 3/4" plywood adapter panel to mount it on so that fits right into the removed window of my basement shop. It's considered a 15" if I remember correctly, and they had bigger sizes too.
 While shopping for one I really focused on the cubic feet per minute of air the fans are supposed to move. I had it all figured out at the time, but theoretically it moves enough air that it exchanges the air in my shop at a rate of something like every three minutes. It's fairly quiet too considering all the air it's moving. With it running I can paint away like mad and you can't tell it anywhere in the rest of the house, in fact you barely even notice it in the shop.

 I have absolutely no idea whether or not it's "explosion proof", but is anything really? ;D