I'm considering getting a fume extractor. I've been doing a lot of stick welding recently (using 6011, 6012 and 6013 electrodes) and I'm concerned about inhaling the fumes, especially when it's cold and I don't want to work with the door open.
I saw this fume extractor on eBay:
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I know the auction has ended, but the seller says it's still available. So I'm just wondering if a machine like this with a paper filter is suitable if the air output remains indoors, rather than being piped outside?
I can't comment on that model, nor am I in England. But a fume extractor is a really good thing to have if you're stick welding indoors!
I have a little fan with a 1/2hp motor and sheet metal shrouding such that it has 2 3" inputs and one 6" output. I have a little 8 foot piece of 6" flex duct I use to run it under my garage door, and I have one of the input ducts taped off (this is what duct tape is MADE for!) and have a piece of 3" flexible stainless ducting I clamp near my welding area. I was using it today even though I was MIG welding - I don't like working in really smoky areas.
I don't know if setups like mine are common, they used to be very common in US West Coast shipyards.
Welding in a closed space with a stick welder is NOT a good idea, glad you are looking at fume extractors.
Hard to tell when I'm 4000 miles away but I don't think this one will be your best option. The tube going into the filter area looks to be about
2" /50mm in diameter. Couple that with the size of the motor and it looks like this will be a medium volume high suction (measured in water column) perhaps something on the order of 300 cfm at 100 inches of water (I quit, I'm NOT going to do all the metric conversions!!) You would want a high volume, medium suction, something on the order of 600 cfm and 30 to 50 inches. You need a 6" or so suction hose that will gather the fumes from an 18" diameter space for best effect.
The paper filter will get dirty fairly quickly, they usually clean up with some serious knock> Hi all,
I have a salvaged blower unit off a forced air furnace for the purpose of venting the shop. It's not hooked up as yet, so how well might this work for welding fume extraction?
Does it need to be vented outdoors or is there a filter that would allow circulation and keep from loosing the heated air in the winter? Is just one hose sufficient to remove the fumes, or is a large hood required Tnks
Venting outside is clearly the best way to do it. Short of a HEPA filter, even the best filters won't clean out all the fumes. But most of the paper based filters or the mid level felt mat funace filters will do an decent to excellent job on the smoke particles.
A furnace blower is usually a high volume, low static pressure device. It will move large quantities of air but any kind of serious filter will block it and possibly overheat the motor (cooled by air over) This would be great for general fume removal from the room to outdoors but would need lots of air filters to keep it working right.
When you use a tube to suck fumes, the usual effective sucking distance is around 2 to 3 times the diameter of the tube. The "Smog Hog" units come with 6" or 8" tubes, workd nicely with the inlet about 12" form the weld.
Another thing to consider is the fume hood style. Enclose your welding bench on 3 sides plus the top, add some edges to the front to narrow the width a bit. With the exhaust fan on the back, even a small fan (200cfm to 300cfm) will give positive air flow from the room, past your body, and out the fan. Properly built with metal sides and top, this is a great way to deal with the fire hazards of the spatter.
The filter for a (proper) welding fume extractor is very special. E.g., a Torit filters something like 99% of 0.2 micron particles. Filters run $100 new, $50 on ebay. Venting to outside is certainly preferable if possible.
Thanks for all the thoughts. On the whole I'm inclined to think that this isn't the best machine for the job. It looks more suitable for dust extraction now I think about it. I'll try to get some kind of system which vents to the outdoors instead. Or maybe just get a fan to place in the doorway. Or build a bench on wheels and weld outside. I'll figure something out.
Roy, thanks very much for that useful advice. You're right that the machine does have a narrow tube and a big motor, so I imagine that using it for welding fume extraction might be similar to using a vacuum cleaner for the purpose. And it doesn't seem to be suitable for venting the fumes outside, either. Probably not the best solution.
I think you hit it on the head. Think about a fume hood sort of affair. As long as the opening is fairly constricted, you can use low volume fan and vent it outdoors. Properly constructed, you can keep the sparks under control as well.
I built a similar setup for a friend who was spraying heavy metal glazes on exotic ceramic artwork. 3'D x 4'W x 3'H work space with some edges,
150 cfm kitchen exhaust fan was enough to totally elim> RoyJ wrote:
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