[delraydella]

What's the best welding fume extractor for the money? I'd like to keep it in the range of $800 to $1000, maybe up to $1200. About 90% of the fumes are from mig steel and aluminium. I'm getting too old to keep breathing this stuff.

Thanks!!

Steve

[Rbeckett]

Delray your gonna have to help us help you. What is your ceiling height, is your ceiling open or covered? How many cubic feet are in the shop? Once we get the basics then an exchange rate that will protect your lungs can be calculated. The max allowable concentrations on some stuff we use commonly is actually very low and requires a lot of excess transfer rate or CFM volume to achieve your goals. But it is all based on shop size calculations and ventilation efficiency coupled to auxillary fume extractors and ducted fans with thermostats and louvers in addition to the type of material you are working with, Galvi comes immediately to mind. Hope this helps get ya going on the basics...
Bob

[ogorir]

I think bob has the right idea, money wise. doing a custom ventilation setup would probably cost you less than a commercial 'fume extractor' if you can do the work yourself. you'd have to watch your airspeed, though, or you'll start pulling your shielding gas out with the fumes.

[delraydella]

Never thought of doing it myself, but why not? What do you mean by an "open ceiling"? If you mean can I see the roof joists from the ground, then it's open.
The ceiling height is roughly 18 feet and slopes down to 16 feet over 50 feet in length (roughly). I'm in about 2500 sq.' of the shop. The entire shop is a little over 10,000 sq. ' I don't know what that would be in cubic feet.

70% of what I do is mig mild steel and aluminium, 15% plasma cutting the same things, 10% tig mild steel and aluminium, 5% arc welding. Sometimes I do galvanized but it's rare. Stainless is rarely, too. Nothing exotic either. Sometimes I have a need to anneal some aluminium, but thats not too often.

Hope that helps.

[ogorir]

I'd really like to know how much air movement you can have before you lose your shielding. I can't find a published number and I don't have a way to measure airspeed. you might be able to get away with running an exhaust fan ducted to a plenum box overhead. that way you're not exchanging everything, and also argon is heavier than air, and I'd expect that you'll lose less shielding if you're sucking from overhead than from anywhere else for this reason.

[delraydella]

If I don't turn off the forced air heater behind me, I lose all my shielding gas, but that heater moves a lot of air. The ceiling fan above me draws up some smoke , but doesn't move enough air to affect the gas, but I have no way to measure air speed either. Suffice it to say it's somewhere between the two on the low end. I can open up the doors for fresh air, but that only works in nice weather.

One shop I worked at many years ago had something that looked like an oven range hood. It worked pretty good, but we only did stick welding there, never mig or tig.

[kermdawg]

In my garage I got my welder set up as close as reasonably possible to the garage door. I open up the side door to get an air flow goin, and I have 2 small variable speed fans I bought from wally world for like 15 bucks a piece. There small enough to reposition them wherever I need to, and I can position myself to weld upwind of the fumes. For doin tig or mig I would just shut the side door and turn the fans down lower and back them up a bit.

When I was learning tig in school, the weld booths we had could not have had much more than a fart fan's worth of exhuast comin out of em.

[Otto Nobedder]

delraydella,

If you're using 1/4 or less of a 10000 sq ft shop, for the processes you describe, you don't need fume extraction. A simple circulating fan to draw the bulk of fumes away from you while welding is adequate; Dilution will do the rest (unless the other 3/4 of the shop is welding stainless without ventilation!)

An open-ceiling shop of this size has adequate general ventilation. Just use a cheap Wal-Mart fan in your immediate work area and you'll be better protected than most production welders.

Steve

[Rbeckett]

Otto hit it on the head. You can get an anemometer at Radio Shack, but why waste the money. If you feel a breeze the shielding gas is generally gone. With a shop that big you just need movement, like Otto said dilution will do the rest. Have a great and happy day!!!
Bob

[delraydella]

I'll give that a try. Thanks!