DIY fume extractor

rkidd · Mar 10, 2018

Looking to make a diy fume extractor for my shop to work in it during the winters here in NE Ohio with the doors closed and heat on. Just doing small welding projects with a mig welder, no flux core and paint these items. I am talking like one foot or 18" stuff. Looked on You Tube and got some ideas for a reasonable cost, as regular fume extractors are pricey! Thinking about going with a 150 or 200 cfm bathroom exhaust fan, ducted outside, and then hang a hose down close to my work area. Any experience or thoughts on this would be great. Thanks.

North Idaho Wolfman · Mar 10, 2018

Real quick and easy one, Stove hood.

Another really effective one, portable dust collector, leave the bag off and put a hose on output, VERY effective!

Yooper · Mar 10, 2018

Did exactly as you're describing before I invested in my (yes, expensive) fume filter. The trick was to position the suction hose close enough to pull away the fumes without pulling away the shielding gas. I rigged up a magnetic holder so I could position it where I was welding, which is almost a must if you want it to be effective. Be careful on the hose selection as the sparks from welding get sucked into it and will burn right through if it is thin. I had some orange colored hose that worked well, but I don't recall where I got it from. I think it was either silicone or fiberglass.

Ike · Mar 11, 2018

My dad fixed up one for jobs similar to what you are doing and it work very well. He used a furnace blower mounted on the end wall of his garage and had a hood over his welding table by the ceiling. ceiling was 8 foot. When you turned the blower on it moved just enough air to take most of the smoke and fumes out. This was using an arc welder. I don't think it would affect the gas on a wire welder but never tried it

chim · Mar 11, 2018

I'm just getting started on an extractor project. From what I've seen, something in the neighborhood of 700 - 800 CFM with an intake near the activity should do it. I ordered a Monkey Arm and a fan. I'll post something when we get it set up.

http://www.monkeyarms.com/welding-grinding

rkidd · Mar 11, 2018

Thanks every one for the replies. Still researching this. Looking at some 6", inline duct fans that have some more cfm now also as an option. Not too bad of a price on some of them.

BravoXray · Mar 12, 2018

I really like Wolfman’s portable dust collector idea, simple and reasonably priced.

Missouribound · Mar 12, 2018

rkidd said:
Thanks every one for the replies. Still researching this. Looking at some 6", inline duct fans that have some more cfm now also as an option. Not too bad of a price on some of them.

That should work just fine. The smaller fume extractors have about 100 CFM fans which isn't much more than a large bathroom exhaust fan. It just has to move the air. A 6" duct fan can be near 400 CFM....that's enough to take care of a larger hood.

North Idaho Wolfman · Mar 12, 2018

Missouribound said:
That should work just fine. The smaller fume extractors have about 100 CFM fans which isn't much more than a large bathroom exhaust fan. It just has to move the air. A 6" duct fan can be near 400 CFM....that's enough to take care of a larger hood.

I hate to disagree with you, but most commercially available smoke and fume extractors are 2000CFM+ units.

chim · Mar 13, 2018

Check the specs on this Miller unit:

https://www.millerwelds.com/safety/fume-extraction/filtair-mwx-portable-fume-extractor-m00328

Yooper · Mar 13, 2018

We are getting into the most important part of air filtration: air velocity. According to calculations, the Miller flows at 2506 fpm through the 8" duct. To get the same velocity out of a 400 cfm fan, you would want to run a 5" duct. (2933 fpm)
https://www.engineeringtoolbox.com/ductwork-equations-d_883.html

Missouribound · Mar 13, 2018

North Idaho Wolfman said:
I hate to disagree with you, but most commercially available smoke and fume extractors are 2000CFM+ units.

I don't mind constructive comments.
Miller makes one with a 135 cfm capacity for small shop use. I did see that the OP wanted one for occasional usage in his small shop in the winter. The $5000 type are overkill for his usage and yes, they do have a more powerful motor and vacuum.....just not needed.
The Miller Filtair 130 would be in the category I was suggesting. If he needs more then of course he would spend more. But even that unit is for light manufacturing. A small ventilator motor would supply similar cfm's with proper ducting and placement. But $1750 is a lot to spend for a small operation when there are other ways to achieve the same result.

North Idaho Wolfman · Mar 13, 2018

Missouribound said:
I don't mind constructive comments.
Miller makes one with a 135 cfm capacity for small shop use.

My Apologies

, I stand corrected, I did not know that they made them that small of a CFM rating.

Russell King · Mar 14, 2018

CFM is cubic feet per minute which is volume/time
FPM is feet per minute which is velocity

Both are used in fan capacity statements but are different values.

I see them both being stated as values that can be interchanged but they can not be interchanged.

Sent from my iPad using Tapatalk

rkidd · Mar 15, 2018

Thanks again everybody. I ended up going with a 440 cfm 6" inline duct fan. I found it on Amazon due nobody had anything local. I got it for $59.00. Anything with that cfm in a bath or kitchen hood fan was in the hundreds of dollars. I got it yesterday, and it even has rheostat feature that I think could be a handy feature. It had great reviews also. I plugged it in and tried it on the bench and air flow seems really good and was really quiet. I am going to go with a 6" dryer vent out through the wall, with the fan mounted to the ceiling attached right to the dryer vent. Then use an extendable dryer hose to get close to my work. This way it will be mounted permanent up out of the way. I will post pics and details after I get mounted.

Yooper · Mar 15, 2018

The other thing to keep in mind is air has to get into the shop to replace the air going out. Another inlet vent, crack a window or a door, etc.

rkidd · Mar 15, 2018

Yooper said:
The other thing to keep in mind is air has to get into the shop to replace the air going out. Another inlet vent, crack a window or a door, etc.

Hey Yooper. I have windows on opposing sides of the garage. I can crack one for makeup air. Thanks.

North Idaho Wolfman · Mar 15, 2018

rkidd said:
I am going to go with a 6" dryer vent out through the wall, with the fan mounted to the ceiling attached right to the dryer vent. Then use an extendable dryer hose to get close to my work. This way it will be mounted permanent up out of the way. I will post pics and details after I get mounted.

Dryer vent hose is only 4"
If that what you want that's fine just please use the non flammable kind.

Here is 6" aluminum duct, if you want that and can't get it locally.

http://www.ebay.com/itm/Deflecto-A0...609485&hash=item25a9edf4d6:g:blMAAOSwPcVVpp5l

rkidd · Mar 15, 2018

North Idaho Wolfman said:
Dryer vent hose is only 4"
If that what you want that's fine just please use the non flammable kind.

Here is 6" aluminum duct, if you want that and can't get it locally.

http://www.ebay.com/itm/Deflecto-A0...609485&hash=item25a9edf4d6:g:blMAAOSwPcVVpp5l

Hey NIW. At Lowes they also had 25 ft long extendable dryer vent hose to go with the 6" dryer vent I found. Not plastic, but the metallic looking stuff. I havent bought it and will have to check to see what it is made of for sure to see if it will work. What you posted looks good. When I find the link I will post it. I for sure dont want to choke it down to 4" after getting everything 6". With the extendable hose I can mount some type of collection hood out of tin from my tinner buddy. Thanks.

North Idaho Wolfman · Mar 16, 2018

rkidd said:
At Lowes they also had 25 ft long extendable dryer vent hose to go with the 6" dryer vent I found. Not plastic, but the metallic looking stuff. I havent bought it and will have to check to see what it is made of for sure to see if it will work.

Please post a link or part # when you get a chance, I'm curious about it.

DIY fume extractor

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