Shop ventilation

[mschrank]

How do you guys deal with ventilation in your shop? Specifically, I'm getting ready to do a bunch of finish work. I was leaning towards water-based varnish to cut down on fumes, but now I've decided I want to go with a solvent based poly or laquer.

In the past, I've rigged up a spray booth of sorts using plastic sheeting for walls. I've only sprayed latex paint, so I just had a regular exhaust fan in the window. But if I'm spraying poly or laquer, I'm a bit nervous about the explolsion hazard with a regular fan. I've seen the "explosion proof" fans, but they're pricey...hard to justify for a even few projects a year.

Spraying outside is not an option. Am I putting myself and my shop at risk if I use a basic exhaust fan while spraying solvent-based finish?

EDIT: Just thought of this....

Would it be OK to put a fan on one side blowing air in and have an open window on the opposite side? Would that eliminate the explosion hazard?

[LCHIEN]

How do you guys deal with ventilation in your shop? Specifically, I'm getting ready to do a bunch of finish work. I was leaning towards water-based varnish to cut down on fumes, but now I've decided I want to go with a solvent based poly or laquer.

In the past, I've rigged up a spray booth of sorts using plastic sheeting for walls. I've only sprayed latex paint, so I just had a regular exhaust fan in the window. But if I'm spraying poly or laquer, I'm a bit nervous about the explolsion hazard with a regular fan. I've seen the "explosion proof" fans, but they're pricey...hard to justify for a even few projects a year.

Spraying outside is not an option. Am I putting myself and my shop at risk if I use a basic exhaust fan while spraying solvent-based finish?

EDIT: Just thought of this....

Would it be OK to put a fan on one side blowing air in and have an open window on the opposite side? Would that eliminate the explosion hazard?

Maybe someone else can back me up on this, but I'm pretty sure that the fume levels coming off a painted object won't be of sufficient concentration to ignite in an explosive manner. If you pull them off with a fan then the concentration won't increase as the air is exchanged and still can't be ignited by the fan.

Only if the space is tightly enclosed and the paint allowed to sit will there be any possibility of reaching explosive levels.

[LarryG]

I would try to put the fan at the rear of the spray area, exhausting outside. That way the make-up air will be pulled into the enclosure past you, which will help limit your exposure to the fumes. Even if they're not at dangerous levels, they'll still be unpleasant, and having the fan blowing away from you will minimize this.

On the explosive issue, I'd turn the fan on before I started spraying and leave it on until after I was finished. That way any arcing that occurs when the motor starts won't hurt anything. Beyond that small and probably overly-cautious step, I wouldn't worry about it.

[mschrank]

Thanks for the replies...and from two of the most distinquished members here

I was thinking along the same lines as you guys...

I'll be spraying either varnish (poly) or laquer and wearing a respirator, so I'm not worried about what my lungs are sucking in. I've only used laquer a couple of times, but remember the fumes being nasty nasty. I'm not sure that necessarily correlates to higher flammability, but I really don't want to blow up my nearly done re-model (not too mention meself).

Larry, good point about starting the fans first...I guess I was thinking that arcing/sparking happens while the fan is on and not just at startup, but that makes sense.