Booster fan for spray booth - looking for suggestions

[nickelplate759]

I have an Artograph 1520 spray booth with a built-in fan.  I've used it with no hose for years, and it's worked fine, but I really want to vent it outside ('cause fumes).  I hooked it up to a 4" diameter vent house, about 4' long, with a 90-degree elbow in it,  that goes outside through a little slotted door - and it can barely move any air now.   Assume it's because of the added resistance  .

So, I'm thinking of adding a (hopefully inexpensive) 4" diameter booster-fan in-line in the hose.    Looking on-line, they seem to range in price from about $20 to $200.

I'm not looking for anything fancy - it will only run when the booth is on, so it doesn't have to be particularly quiet, nor have a speed control.

Anyone have any experience to share?

[MK]

Look for 4" box fans, typically from computer equipment from 10-20 years ago.  The 4" (120mm) fans used in PC's now a days are a bit fragile.

[ednadolski]

I am not at all sure whether multiple serialized blowers would have any cumulative effect, or it would just be limited by the lowest-rated unit.   At that point, why not just upgrade the original blower?

IDK if a larger diameter duct is an option, but 4" sounds small-ish, esp. if not rigid metal.  6-inch ducting would probably be way better.   (Mine is 8", but otoh my centrifugal blower is 1250 CFM and can extinguish a lit candle.) (There is nothing quiet about it, lol)

HTH,
Ed

[nickelplate759]

I am not at all sure whether multiple serialized blowers would have any cumulative effect, or it would just be limited by the lowest-rated unit.   At that point, why not just upgrade the original blower?

IDK if a larger diameter duct is an option, but 4" sounds small-ish, esp. if not rigid metal.  6-inch ducting would probably be way better.   (Mine is 8", but otoh my centrifugal blower is 1250 CFM and can extinguish a lit candle.) (There is nothing quiet about it, lol)

HTH,
Ed

Fans in series can indeed help - that's not in question.  I'm just trying to find a decent fan to use.   

Regarding another suggestion in this thread, in fact, some of the cheap-o kits for doing this are indeed just computer-style box fans with a housing.   As you note, quality is variable - that's always been the case with computer case fans.   

Changning the fan in the spray booth is non-trivial, and I'd prefer just to put a booster in-line.

[Maletrain]

Because you are talking about venting solvent fume don't you need to have a fan that is rated "ignition proof"?  That usually just means that nothing sparks where the air flows while the motor runs.  With only a double-action air brush, the fume concentration would probably stay below the flammability concentration, but maybe not with some rattle cans.

[Lemosteam]

Search or grow fans on Facebook marketplace. I have a 8” and it’s quiet and powerful that I bought used for $40. Saw some much less too.

[ednadolski]

Fans in series can indeed help

Interesting, tho I am wondering how much.  Surely, something like say 100 CFM in series w/ 100 CFM would not come out anywhere close to 200 CFM?  (or even 150, esp. with no change in ducting capacity).  So maybe you could pick up say 10%?  20%?  But I have no idea how one might compute that sort of thing. It may be interesting to see if you could measure the before/after airflow with one of those small hand-held anemometers  ($10-$20 on Amazon).

Ed

[garethashenden]

I have an Artograph 1520 spray booth with a built-in fan.  I've used it with no hose for years, and it's worked fine, but I really want to vent it outside ('cause fumes).  I hooked it up to a 4" diameter vent house, about 4' long, with a 90-degree elbow in it,  that goes outside through a little slotted door - and it can barely move any air now.   Assume it's because of the added resistance  .

So, I'm thinking of adding a (hopefully inexpensive) 4" diameter booster-fan in-line in the hose.    Looking on-line, they seem to range in price from about $20 to $200.

I'm not looking for anything fancy - it will only run when the booth is on, so it doesn't have to be particularly quiet, nor have a speed control.

Anyone have any experience to share?

I basically did the same thing six months ago, its been a huge improvement. I can't remember exactly why I settled on this one, it may have been price, but its working better than the original setup. The paint no longer bounces back at me.
https://www.amazon.com/dp/B01M7S46YZ?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1&th=1

[Maletrain]

Interesting, tho I am wondering how much.  Surely, something like say 100 CFM in series w/ 100 CFM would not come out anywhere close to 200 CFM?  (or even 150, esp. with no change in ducting capacity).  So maybe you could pick up say 10%?  20%?  But I have no idea how one might compute that sort of thing. It may be interesting to see if you could measure the before/after airflow with one of those small hand-held anemometers  ($10-$20 on Amazon).

Ed

Probably substantially less than 40% increase, based on simple physics speculation.  (Details: power transmitted to the air motion is "Q" times some coefficient, and Q= 1/2 x air density x air velocity squared.  So doubling the power put into the air should produce the square root of 2 = 1.41 times the air speed.  But, there is also the additional drag of the air from the first fan going through the structure of the second fan, so something less. And the drag losses of the air going through the duct is also proportional to Q, so more loss due to higher speed of the air.)

[nickelplate759]

I basically did the same thing six months ago, its been a huge improvement. I can't remember exactly why I settled on this one, it may have been price, but its working better than the original setup. The paint no longer bounces back at me.
https://www.amazon.com/dp/B01M7S46YZ?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1&th=1

OK, just ordered one - for $30.00 it's worth an experiment.    Thanks for the link.

[ednadolski]

TMI alert: Some further info about performance of multiple fans in series or in parallel:

https://forum.digikey.com/t/does-stacking-fans-double-the-cfm/10553

https://www.ecooling.com/wp-content/uploads/2020/01/ATM-2017_WagnerPresentation.pdf

Ed