[mcoe]

I have a quick question about the effects of a fume extractor on the shielding gas of Mig and Tig. I know they are both wind sensitive and since stick and flux core produce a form of slag covering instead of gas cloud I was wondering if a fume extractor would effect the gas shielding? I don't have one or the money to get one to try it but at school I have used them and personally I think my welds at home are better than the ones at school, the machines are different but I have also ran the same machine at work without an extractor and feel they are better. Just a theory/question wanted to see what your opinions are.

[Arizona SA200]

With flux core and SMAW there is a shielding gas created when the flux is melted and this can be affected by wind because most of the puddle is covered with slag. It is hard to affect it but it happens. With MIG and TIG you will need to keep the extractor far back from the pieces being welded. If you can hold a cigarette lighter where you are welding that is usually a good indication the you will get adequate shielding gas coverage.

[Arizona SA200]

The same test can be done the opposite for purge. IF the flame goes out due to lack of oxygen purge should be adequate.

[mcoe]

Thanks I was just wondering about it and like I said, I never use a fume extractor I just know I have been told Mig and Tig is wind sensitive and it made me think. I thought I would ask everyone. Thanks for the info I never heard of the lighter test.

[Superiorwelding]

Here is a video by Mr. TIG using a downdraft table. He covers a lot of different things, including sucking your shielding gas away.
http://www.youtube.com/watch?v=Rxo5SLrnFF0

[mcoe]

Thanks for the video. I watch a lot of his videos but have never seen that one. Up here at college, again I am not at welding school, they have us put the fume extractor right on the table as close to the weld as possible. I am an education major and they are teaching us to teach our students this. I never used a fume extractor until I came here. I always used an exhaust fan that wasn't close to the table. I just thought that something didn't add up.

[AKweldshop]

Mig(gas shielded bare wire) and Tig put off very little fumes.
Stick and FCAW put off a considerable amount.
I wouldn't think you would need/use a fume extractor for a gas shielded process.
2 cents,
~John

[mcoe]

That was my thought exactly. I learned to weld in high school on old Lincoln tombstones and we had an exhaust fan in the wall above the welders and duct work up to it from each booth and I never had trouble. I came to college and they have a bunch of fume extractors and they use them for every little project. Again this is not a welding based major but they cover basic welding and I think they are going about it the wrong way but when I said something to the professor he said I didn't know what I was talking about. I just wanted your opinions. Thanks for all the input everyone. I really appreciate it.

[newschoppafowah]

Mig(gas shielded bare wire) and Tig put off very little fumes.
Stick and FCAW put off a considerable amount.
I wouldn't think you would need/use a fume extractor for a gas shielded process.
2 cents,
~John

That's always been the way I've played it. I did a project where I was using Flux Cored Wire on galvanized tubing and built a fume extractor out of some stuff I had on hand. That was a definite good move.

I've never worried about fumes on bare wire MIG or TIG, but from time to time you pick up some burning paint, or mineral oil if you didn't clean the inside of some square tube, for example, etc. Some satellite contaminants, if you will, burning off and up into your helemt, but I've always figured a fume extracting system would compromise the shielding gas (especially with TIG) so I've just rode with the occasional unpleasant burnoff.

Just like the fella I quoted, this is my 2 cents. I'm no scholar on it.

[mcoe]

I am the type who wears a welding respirator so I really don't worry about fumes.

[Superiorwelding]

When stick or self shield welding, there is nothing wrong with the fume extractor being right in your face. If you could put smoke coming out of your TIG cup and hold it down near the extractor, they would be able to see how much gas is getting sucked away. They might have a reason they want you to do that. I know our LWS puts their extractor right down to the gun when I test new equipment in their store. They have a separate room set up for testing but want absolutely no smoke or smells wandering into the showroom, and I cant blame them.
MIG will put a lot of smoke out as well. Within a hour we start the fan to start getting the smoke out.
Story; I once argued with someone who always wanted the fan on to get the smoke out of the shop. His theory was he wouldn't breath smoke in with the overhead fans on. I pointed out that the same smoke is going past his head with or without the fan on, the only difference is how long the smoke lingers to breath. I would love to get downdraft tables for the shop, but most of our weldments are to big for a table. Maybe I could build one like Jody did. Hmmm...

[Braehill]

I used to work with a guy who seldom if ever struck an arc without one of those little black cigars in his mouth, he needed a fume extractor for his helmet. Once a safety guy told him he couldn't smoke because of the fire hazard as he was lighting his torch off his cigar, ironic and a litle funny. I told him that smoking cigars was going to kill him, and little did I know, two days later he would be burnt to death in a refinery fire and he was neither smoking or welding at the time.

Wearing a respirator isn't a bad idea, but it doesn't exclude you from the need for fume extraction, as they don't filter all harmful chemicals out of the fumes, unless you're using a fullface supplied air mask.

Len

[jumpinjackflash]

Anyone ever thought of getting some stuff at the Lowes store and making a small unit for shop table use on the cheap? I was thinking along the lines of a small fan in the wall for a louvered vent outlet and dryer duct mated to it down to the weld area. Most things I weld are small and will be sit down at the table and get to it type work. My weld table top is 1/4" steel and I could use an old dial indicator magnet base to hold the duct tube in place. Or would a down draft unit made up from grating be better for TIG? A long time ago when I worked in a cabinet shop there was a duct at each saw or shaper. You would just slide the valve open and cut away while all dust/chips were sucked away to the great outdoors. It was a nice vacuum system....I remember the carbon arc guys welding up the pipe. Haven't messed with stainless yet...but I know I will soon. Better safe than sorry knowing of material hazards in different metals when welded.

[Superiorwelding]

I think the vent idea would work. Give it a try and let us know how well it works, who knows you may be on to a great idea.
When I can get some projects caught up, I think I will make a downdraft table like the one Jody made. I would especially like it for plasma cutting.

[Arizona SA200]

Hey superior what about having a funnel type set up with a fan set up on one side of the table for fume extraction and a removable tray on the other side for clean out??? May have an idea for a good little cutting table here.

[Superiorwelding]

That's a good idea. I think it would work well. I will have to let this brew and come up with some plans. I will start a new thread and see what ideas are out there.
-Jonathan

[mcoe]

I stumbled across this today while making a wish list. It also offers duct work.
http://www.harborfreight.com/garage-sho ... 97762.html
http://www.harborfreight.com/garage-sho ... 97763.html

[Superiorwelding]

Matt,
That seems like a very cost effective alternative. That should work very well.
-Jonathan

[mcoe]

That's what I was thinking. I'm not sure what the duct work is made of but if it was me I would probably put it up high where it will be out of the way and sparks shouldn't get to it.

[Arizona SA200]

That looks like a manhole blower for confined space ventilation. They draw a lot of air i know that but maybe you could build a restriction plate set up for it so that it would be adjustable.

[mcoe]

That's not a bad idea. I looked it over a little bit today when I stumbled across it but never gave it much thought. Now I'm thinking about getting the thing once I finish reworking our shop.

[Arizona SA200]

And BTW the duct work on those is on the discharge side of the blower.

[mcoe]

Oh I just read the reviews on it and this one guy said he used it when he did a welding demo at his local fair and loved it. I just read another one that said he put the duct on the suction side and it lost suction but still worked but wouldn't recommend it. I guess if I would have read a little I would have saw that.

[RichardH]

I stumbled across this today while making a wish list. It also offers duct work.
http://www.harborfreight.com/garage-sho ... 97762.html
http://www.harborfreight.com/garage-sho ... 97763.html

I went to a welding demo at an art joint where they used something like this with the unit sitting on the welding table and the exhaust duct run elsewhere. It seemed to work just fine, though a bit noisy.

I've been noodling something like this in the attic, wired to a dimmer for speed control. Rigid duct to a vent outside, and flexible aluminum dryer duct down to the work top. They have a ton of sizes, speeds, with/without cords, etc. I understand their CFM is on par with a bathroom exhaust fan.
http://www.homedepot.com/p/Suncourt-Ind ... /100073963

Cheers,
Richard

[450dualsport]

I would like to have a small fume extractor as well.

The Harbor Freight unit that Matt posted the link to looks good as it would be portable. However, at 1400 - 1575 CFM I would think it would need to be dialed down quite a bit for MIG or TIG work.

This small unit is 113 - 226 CFM

http://store.cyberweld.com/acewefuex.html

so Richard's idea of somehow using the inline duct fan may be better provided it could be made portable.