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[machinist] Range Exhaust Hood for Extracting Welding Fumes--Good Idea?
- From: Lawrence London <lfljvenaura@gmail.com>
- To: machinist@lists.ibiblio.org
- Subject: [machinist] Range Exhaust Hood for Extracting Welding Fumes--Good Idea?
- Date: Sat, 30 Nov 2013 00:04:55 -0500
http://www.practicalmachinist.com/vb/general/range-exhaust-hood-extracting-welding-fumes-good-idea-275818/
Thread: Range Exhaust Hood for Extracting Welding Fumes--Good Idea?
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Range Exhaust Hood for Extracting Welding Fumes--Good Idea?
So I am setting up a small welding station in the corner of the machine shop to weld some small parts. I have this idea of putting a good quality range hood above my little welding table and venting it out of the side of the wall. Does that seem like a good idea?
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11-25-2013, 02:16 PM #5
- Join Date
- Jan 2008
- Location
- Merced, Calif
- Posts
- 804
Anything is better than nothing ---- the problem always is getting the air flow close enough for the smoke to travel to the hood without causing a cross draft that interferes with the shielding gas ------most range hoods are very low in cfm's , ---- there are recommendations online somewhere for minimum air flows --
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Oh, so now it's OK to pollute
Originally Posted by munruh
Ok.......I live in country so that shouldn't be a problem.
just kidding.
You can probably do as JMG suggested and find one on CL. There's a fine line between moving fumes and disturbing the shield gas. Mount the hood about 24-36" about the welding bench. You might have to block one side of the bench so that you only pull from the front. So much depends on what kind of welding, static pressure in the shop, etc, etc. etc.
JR -
I would think so, you may want to try it setting vertical in front of you as you weld as opposed to above to see if you can get the air to flow away from your face first then out with walls on the top and sides… just a thought.
If the air flow is too high (pulling your inert gas away) you may have raise it up some to find the sweet spot between it going in your face and pulling your gas. A diming light switch might work also to slow the fan more but I’m not sure about that. Harbor Freight had some cheap variable frequency switches, a friend bought one for his small belt sander to slow it down.
Adding to JR's comments.Last edited by scadvice; 11-25-2013 at 02:38 PM. Reason: JR beat me...posting
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11-26-2013, 07:11 AM #9
- Join Date
- Sep 2011
- Location
- Mid-Atlantic USA, South China
- Posts
- 7,986
Faber Magnum we have in one of our kitchens would probably do the job. Be sitting down when you price one. Originally Posted by munruh
Ok.......I live in country so that shouldn't be a problem. Just wondering about the concept.
Recycled kerb-mount rooftop or through-the-wall rig from a commercial kitchen / pizza place could be better.
Variable-speed essential, regardless.
Also don't forget to provide bespoke or 'hasty' make-up-air if the shop is enclosed.
Bill -
Well lets see here, the answer is no. I do design build for commercial Hood's / make-up air systems and many fume exhaust systems under my belt . Your over complicating a simple process. In general welding fumes should be captured at the source with an exhaust arm / Down Draft table. If you must put in a hood, don't forget a hood is box with an exhaust collar. A simple TYP-2 hood will work / if you must have a hood ,I would design a sheet metal hood at 150 CFM a Lineal Ft Min, Size the duct at 1,500 FPM to 1,800 FPM. Buy an inline fan with a variable speed controller to fine tune your exhaust for capture. You can find a pretty cheap fan on Ebay with speed controller. Depending on how far duct is ran, Fan Static will need to be considered.
There are many factors that can affect hood performance. Location in shop I.E Side drafts can push the exhaust plume out of hood capture zone, and might require side skirting. Make-up air can be a major factor in hood performance. If this will have light use and it's located in a big shop no worries about Make-up air. P.S. There is a wealth of info on Hoods. I think you will have better luck with google than this sight. Good Luck -
Anything is better than nothing. Settled welding and grinding particles can be very dangerous.
We scrounged up a 3ph motor and a squirrel cage with a damper we built in line. -
11-29-2013, 08:53 PM #12
- Join Date
- Jul 2011
- Location
- Navasota / Whitehall Texas
- Posts
- 73
Here is one I made for a shop in Houston
The first is a picture of a hood that is working very well... Under the Hood are a couple of flood lights. Without the lights its very dark because the hood blocks the overhead lights.
Also built a little cutting / welding table to work on...
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- [machinist] Range Exhaust Hood for Extracting Welding Fumes--Good Idea?, Lawrence London, 11/30/2013
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