Home made fume hood / paint booth

AlamOso · September 15th, 2004

Check out some pictures of a fume hood that I threw together - it works pretty well.

http://www.rivercitylures.50megs.com/mach/fume/fume.htm

ckarren · September 15th, 2004

That is what I need for my sander!! Add two holes and attach two gloves so the whole thing is enclosed.

Thanks

AlamOso

-Corey

Hwy-Apostle · September 15th, 2004

Um not to be a stick in the mud but isnt haveing a vacume (ie electric motor) pull flamable fumes threw it a bad idea

. not trying to nock the concept just pointing out a safety thing here.

Tally · September 15th, 2004

AlamOso
I am sure you know what your doing, but make sure your lights are sealed from the fumes. When everything is inclosed the risk of explosion is greater. Just be safe, we don't want to read about you in the obit's. If all is safe, great idea.
Tally

AlamOso · September 16th, 2004

I think that you guys have some valid concerns. I only claim to "know enough to be dangerous".

Hmmm...now where can I find a volunteer to test it out with pure paint thinner and acetone?...Maybe my brother-in-law!

Seriously, I do think that the shop vac could be of concern. I believe the air goes into the tank before it is exhausted. One spark in that compartment and the lid blows off for sure. As far as the light, I guess any potential spark source is a risk.

You guys sure know how to take the fun out of being a mad scientist! If you know of any suggestions on how to make it a safer operation, please follow up.

Thanks.

Coley · September 16th, 2004

As far as the light goes you are safe as long as it is turned on
before you start. The switch is where you will get your spark.
You could use a squirrel cage fan set up outside. Get a fan
that has the motor outside the fan housing. Attach a piece
of 4" flexable sewage hose to the inlet and seal around the
motor shaft leaving about 1/4" clearance. This will allow fumes
to be pulled into the fan through the inlet hose and fresh air
pulled in around the shaft, No fumes can build up in the area of the motor.

Coley

Hwy-Apostle · September 16th, 2004

Coley I agree a hundred percent with one mod use a plastic fan incloser ie. one from a car heater setup. but run it from an external motor that has a pully on it and a pully on the impeler fan. that way there is not only no fume buildup but also no fumes near a spark. Also turn this on b4 you start to spray.

Tally · September 18th, 2004

AlamOso
Brother n laws are good testers, especially the one's that always want to borrow the boat. Nothing wrong with being a mad scientist, just stay a couple steps behind crazy. :P
Tally

Finneous Fogg · July 11th, 2005

Quote:

Originally Posted by AlamOso

I think that you guys have some valid concerns. I only claim to "know enough to be dangerous".

Hmmm...now where can I find a volunteer to test it out with pure paint thinner and acetone?...Maybe my brother-in-law!

Seriously, I do think that the shop vac could be of concern. I believe the air goes into the tank before it is exhausted. One spark in that compartment and the lid blows off for sure. As far as the light, I guess any potential spark source is a risk.

You guys sure know how to take the fun out of being a mad scientist! If you know of any suggestions on how to make it a safer operation, please follow up.

Thanks.

Anybody ever see the TV show "Mythbusters"?
They test urban legends to see if they are truth or myth.
The exploding shop-vac thing is a myth. They tried to turn a shop-vac into a jet engine using the theoretical myth. They tried everything they could to get that shop-vac to burn. It never did.

jm · July 20th, 2005

Any contained flammable gas is a concern. an open drum with a little paint thinner and a spark goes whoosh. a closed drum and a spark causes death. It has to do with the dynamics of combustion under pressure. I don't care what the myth-busters say, if you want me to destroy your shop vac with 1 oz of lacquer thinner, it would be an easy thing to do.

A shop vac has a series wound motor ( with sparking brushes) that is cooled by the air (supposed to be) going through the machine.

A squirrel cage fan.blower with an external motor, either belt or direct driven should work just fine and be safe. It would also be a lot quieter and use much less power. W. W. Grainger has a 60CFM blower that we use for air supply to a small wood furnace, and many other uses that should be easily adaptable to something like this. In the north, greenhouses use a small, inexpensive blower to keep the layers of plastic separated. Possibly a source.

The fume level while you are working wouldn't be enough to 'blow', but if you forgot and let a bunch of solvent evaporate in the hood, then turned on the vac, it could get more exciting than you want to deal with. I guess it depends on how much risk you or your brother in law want to take.

Lights are the same. The best way to light a paint booth is by lights that shine through gasketed (fume proof) tough (Plexiglas) windows from outside the actual booth. The light switch is either explosion proof or in another room entirely.

Be a safe mad scientist.

jm