Fan for extracting fumes

[Billgluckman]

I know it’s been beat to death and the consensus is to use only a brushless motor fan, my question is does anyone have any recommendations on a fan? I’ve got a small 16x22 shop that I weld in and occasionally paint in. I’m not sure how many cfm I need or how to tell which fans are actually brushless.

I’ve read about using bathroom fans but I haven’t seen any concrete info on if they’re actually brushless. Hoping to find something that isn’t stupid expensive

 

[Bretny]

Bathroom fan wont flow enough. Whats wrong with opening your door and useing a barrel fan?

 

[rlitman]

All the bath fans I've seen are shaded pole motors. They're VERY limited in flow though. It might work for welding fume extraction if you have the inlet ducted inches from your work, but is pretty nearly useless for any painting.

 

[dogdog]

I think it dependents on your area.... for welding you don't want too much CFM that it ***** off the gas before it can protect your welds, for paint, you are suppose to use an explosion proof motor... for some weird reasons... There is a youtube guy that build one out of those squirrel fans from hvac blowers... I think it was a nice design... have to find that link again...

found it...
this one..

maybe OP can make a down draft table for his welding thing... and use the same ducts and blower for both... I think Jody weldingtipsandtricks have a good video on that one...



I have a ducting and axle fan from HF that I used to place near where I am welding and exhaust the fume out to the windows... it's sealed motor.. but they don't sell the ducting any more ....

https://www.harborfreight.com/8-inch-portable-ventilator-97762.html

 

[dogdog]

All the bath fans I've seen are shaded pole motors. They're VERY limited in flow though. It might work for welding fume extraction if you have the inlet ducted inches from your work, but is pretty nearly useless for any painting.

The newer Panasonic ones have a 270CFM rating and it's a DC brushless motor...

https://www.build.com/panasonic-fv-...MIwInw5tnj3gIVFsDICh0-Ygk4EAQYBSABEgJv_PD_BwE

Costco used to sell a generic copy of that for $50... not sure what happened to it, it seems like it's a seasonal item or discontinued... but it looked exactly like the Panasonic one... permanent magnetic brushless DC motor...




you can still see the link but some reason product is not listing in their site any more.


http://costcocouple.com/delta-breez-humidity-sensing-bath-ventilation-fan/

 

[Negen]

Bathroom fans are not a good idea due to plastic impeller. You want a squirrel cage fan. Metal if you can find one.


Some heavy gauge sheet metal and a furnace blower fan. Make box. Some 6 or 8" flex tube to your work station. Connect that to a forced air vent like this. Add metal vent cover. In the Hood above your work station you should put a metal metal filter to act as spark arrestor. Total fab cost should be about 200$ I would think.

https://www.zoro.com/dayton-blower-146-cfm-115v-075a-3100-rpm-1tdp7/i/G2445581/

 

[Billgluckman]

Bathroom fan wont flow enough. Whats wrong with opening your door and useing a barrel fan?

Opening a door when painting is an invenation for bugs and it lets all my good warm air out in the winter if I’m welding(but I guess s fan will do the same). I do normally open the door when welding though, mostly concerned with paint fumes.

To everyone else-good info and thanks. I’m checking the links when I get home.

 

[bullnerd]

Scroll down to post 12.

https://www.garagejournal.com/forum/showthread.php?t=225559

 

[Billgluckman]

I think it dependents on your area.... for welding you don't want too much CFM that it ***** off the gas before it can protect your welds, for paint, you are suppose to use an explosion proof motor... for some weird reasons... There is a youtube guy that build one out of those squirrel fans from hvac blowers... I think it was a nice design... have to find that link again...

found it...
this one..

maybe OP can make a down draft table for his welding thing... and use the same ducts and blower for both... I think Jody weldingtipsandtricks have a good video on that one...



I have a ducting and axle fan from HF that I used to place near where I am welding and exhaust the fume out to the windows... it's sealed motor.. but they don't sell the ducting any more ....

https://www.harborfreight.com/8-inch-portable-ventilator-97762.html

That harbor freight fan looks like a good buy. In the description it says it can be used for painting but spraying paint with an hvlp is different than painting with a brush/roller so I’m wondering if it is suitable?

 

[Billgluckman]

Scroll down to post 12.

https://www.garagejournal.com/forum/showthread.php?t=225559

I’m watching classifieds for that style fan but I’m not coming up with much yet. Looks perfect though

 

[gunguy]

Placement is important as well as some fumes/vapors are lighter or heavier than air. Also, try to avoid pulling the fumes past your breathing zone.

Jim

 

[LS6 Tommy]

The reasons for using an explosion proof motor for painting are not "weird", they're common sense. Paint fumes can be very combustible. Paint overspray can be even when it's dry. Dust explosions are not fun.

Tommy

 

[dogdog]

That harbor freight fan looks like a good buy. In the description it says it can be used for painting but spraying paint with an hvlp is different than painting with a brush/roller so I’m wondering if it is suitable?

I don't know what the differences is between spray paint and hvlp automotive two stage paint or single stage or Urethane v. Acrylic....

But I think it is either a sealed motor for explosion proof or not situations for any chance the combustible fumes or right combination of dust to air ration to ignite (granted it's a HF item).... I have the HF ones , but mostly used for dust extraction when I needed to ventilate a room from dust. And it's been great so far... a bit louder than when it was new... but hey... it's a HF item and it's been few years going through a lot of dust.


Anyways there are few very old threads here that have plenty of "DIY fume extractors" people build using this unit around a small size cabinet the size of a roll around cart on this, with the Home HVAC filters(more than 2).... just search here if that is something smaller mobile scale that you wanted.

Larger scale for home is that Squirrel cage video...

I think there was a thread of a custom paint booth here.. or was it on a different site.... on commercial scale. Not sure what they use... but definitely know the motor is explosion proof ones... supposedly...

 

[dogdog]

The reasons for using an explosion proof motor for painting are not "weird", they're common sense. Paint fumes can be very combustible. Paint overspray can be even when it's dry. Dust explosions are not fun.

Tommy

yes only if the fumes travels over the motor, like an in-line fan, like that HF unit needs.... but if it is separate outside of the housing like a hvac squirrel cage, it shouldn't cause problems... you'll have to have a very dense over spray with the correct air ration... and the fuel leaked outside of the ducts into the motor some how conditions.... so ...YMMV on the situation is what I mean.

as far as brushless, brushed, or most AC motors don't have a brush... so not even sure what OP is asking either... but definitely a sealed motor would have prevent those dust / paint over spray from accumulating and destroying the motor faster than normal...

BTW, OP, that HF is just an example, there are plenty of people that sells those unit better ones, just at a higher price...

 

[LS6 Tommy]

yes only if the fumes travels over the motor, like an in-line fan, like that HF unit needs.... but if it is separate outside of the housing like a hvac squirrel cage, it shouldn't cause problems... you'll have to have a very dense over spray with the correct air ration... and the fuel leaked outside of the ducts into the motor some how conditions.... so ...YMMV on the situation is what I mean.

as far as brushless, brushed, or most AC motors don't have a brush... so not even sure what OP is asking either... but definitely a sealed motor would have prevent those dust / paint over spray from accumulating and destroying the motor faster than normal...

I forgot to mention all that. Thanks for pointing it out. I will add that most residential HVAC squirrel cage blower motors are direct drive, air over, open motors and they're inside the blower wheel housing, they haven't been belt drive in decades.

Tommy

 

[Sureshot]

Where are you located?

Talk to an HVAC company and let them know. Those fans should be easy to come by.

 

[dogdog]

I forgot to mention all that. Thanks for pointing it out. I will add that most residential HVAC squirrel cage blower motors are direct drive, air over, open motors and they're inside the blower wheel housing, they haven't been belt drive in decades.

Tommy

Yea I don't work on HVAC stuff much, only when my things break...


the one I had in mind are these.

https://www.zoro.com/dayton-blower-965-cfm-115v-350a-1020-rpm-1tdt5/i/G1996635/


I am guessing you are referring to
https://www.zoro.com/dayton-blower-465-cfm-115v-290370a-1530-rpm-70635176/i/G0939976/

 

[Billgluckman]

Bathroom fans are not a good idea due to plastic impeller. You want a squirrel cage fan. Metal if you can find one.


Some heavy gauge sheet metal and a furnace blower fan. Make box. Some 6 or 8" flex tube to your work station. Connect that to a forced air vent like this. Add metal vent cover. In the Hood above your work station you should put a metal metal filter to act as spark arrestor. Total fab cost should be about 200$ I would think.

https://www.zoro.com/dayton-blower-146-cfm-115v-075a-3100-rpm-1tdp7/i/G2445581/

The motor on these are completely sealed from the inside right? These aren’t as expensive as I thought they were

Another concern if cfm. I just looked up the cfm on a cheapo box fan I have that apparently flows around 2k cfm. I didn’t think it moved that much air. I guess I could start with 500cfm and see how well it works.

 

[BruceMc]

Somebody can correct me if I'm misremembering, but CFM ratings are best-case estimates and the real world flow can go down quickly once you start adding in duct work, grating, etc.

 

[sberry]

Small twin box fan with furnace filter in front of it. Make a variable intake on the building to be able to tune the draw. A small rubberband on the walk door is a good start. Uou have to let some air in. Not so much it doesnt create negative pressure. Draw is what moves air.

 

[cattflight]

This is an explosion-proof fan designed for exhausting fuel vapor from the bilge of a boat. I bought 4 of these and installed them through holes in a board on the back of a 6'x6'x7' paint booth. Then I ran short flex hoses out to another board inserted in the lower part of a double-hung window (it's removable so I only rig it up when I need it).

I don't even smell the fumes when spraying and I know it's working because I can see the color of the paint on the mesh screen on the window board vent openings.

 

[xman_charl]

use this contraption

below it is a lexus i bought for my wifey.

fan is from hf

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Charl

 

[Billgluckman]

I’m all in on the furnace fan. Thanks everyone.