Ventilation

[kdavis]

I have been using a mig welder in my shop which has little ventilation, I was wondering if anyone has any inexpensive ideas that I could try, to make some type of ventilation system?

[Jeepnford]

I haven't actually installed it yet so I'm not sure how well it will work but I'm going to put an attic fan up near the ceiling. The main downside I see is with winter coming along it'll suck out the heat also.

[Fishy Jim]

What kind of access to exterior walls do you have?

In my shop, I used a 24" "whole house fan" which is hard wired into an automatic attic power vent. When welding or cutting, I turn the fan on, which sucks the fumes into the attic and then the vent pulls it out the roof.

With the 11' ceiling, sparks making it that far is not a concern as long as I watch where they're going with heavy grinding ops. Regular spatter isn't an issue.

The pair combined was less than 300 bucks. I over sized their capacity by 200% to ensure that they have sufficient flow to move enough air for my purpose.

If you don't have the option of going "up" you could implement any number of exhaust fans. I'd put a filter on the inside of anything being discharged out the side of the house, as you'd end up with streaking over time otherwise.

[Goodhand]

Years ago, whenever I was doing quite a bit of stick in my little shop, the smoke cloud got to be more than I could tolerate. I grabbed a squirrel cage blower out of a discarded clothes dryer, some flexible dryer hose, a garbage can lid, some light nylon rope, a couple of pulleys, and rigged an exhaust system. Cut a hole in the lid for the hose connection. I suspended the can lid over my project area on the rope and strung it through the pulleys with a counterweight on the other end. Now, I could just reach up and pull the vent hood (lid) over the work piece to suck up the fumes. Problem solved; exhausted the fumes without taking a lot of room heat, too.

[SignWave]

heres an idea for you.

look up th elocal furnace guy in the phone book. Find one of the bigger guys and find out where his base is. Since winter is fast approaching, may old gas fired furnaces will be throwing in the towel. If you go by their yard you might just see an old furnace standing there. I got one that had two fans in it. A small circulation fan (sortof resembles a snail) and a blower fan and housing (sortof resembles a wide, fat snail) the larger of the two usually sits at the bottom of the furnace enclosure and have a 1/4 or 1/3 hp electric motor in them and they push ALOT of air. you could rig one of these up if your lucky enough to find an old furnace.
some have two speed motors too, so you could have varied levels of extraction.

Check it out. its worth it. Ive used mine to vent paint fumes, sandblasting dust, and smoke. it works like a charm. the draw back is the shape. its a little hard to mount, but with a welder and some sheet metal... I'll leave it at that. Good luck.

[Fishy Jim]

I actually have a 5 speed squirrel cage fan like those used in furnaces. Picked it up surplus for 20 bucks (cheaper than curbside supply roving around here).

I'm using that in the paint booth.

You can use them in a duct just like the Jet and Grizzly air cleaners. Pretty easy to mount that way. Make a box with a baffle for the fan to mount to, filter in, filter out - done.

The issue with the high flow fans and point of use exhaust and welding can be inducing drafts across your arc. I went with the slower velocity ceiling exhaust option for that reason alone. I also made my windows well above working height so that drafts have a greater likelihood of blowing over my bench than across it. Cross ventilation was a big design consideration with where my doors and windows are located.

So far, it's all working great too. I can stand in my shop and feel the breeze with the windows and doors open, but loose reciepts and light papers won't flutter on a table.

[SignWave]

I actually have a 5 speed squirrel cage fan like those used in furnaces. Picked it up surplus for 20 bucks (cheaper than curbside supply roving around here).

I'm using that in the paint booth.

You can use them in a duct just like the Jet and Grizzly air cleaners. Pretty easy to mount that way. Make a box with a baffle for the fan to mount to, filter in, filter out - done.

The issue with the high flow fans and point of use exhaust and welding can be inducing drafts across your arc. I went with the slower velocity ceiling exhaust option for that reason alone. I also made my windows well above working height so that drafts have a greater likelihood of blowing over my bench than across it. Cross ventilation was a big design consideration with where my doors and windows are located.

So far, it's all working great too. I can stand in my shop and feel the breeze with the windows and doors open, but loose reciepts and light papers won't flutter on a table.

I hear ya on that draft thing. I found an old house fan in the garbage. The guy threw it out because it cut out when it oscilated. The fan gets jammed in an open window an the other window gets opened. this works really well and i can evacuate the shop in about ten minutes. Mind you im only clearing the air from about 300 sqft (2400 cubic ft?) so this is a good balance. the draft is mild and it does move enough air that im not getting stoned on flux smoke or paint fumes... And the stand, well the stand got turned into a perch for our cockatoo. She likes to take big craps from it....and they dont hit the floor! (thats the part i like..) nothing like bird sh t to clean up. stuffs' worse than battery acid.

[Fishy Jim]

Yeah, I have two speeds on the whole house fan and on high it'll really make some air move. I'm glad I can turn it up, but I'm really glad I can turn it down.

Fresh air is very important in a shop. All that stink isn't doing your lungs any favors. Might seem obvious, but you need somewhere for the air to get in if you're gonna blow any of that crap out.

Heat loss is a necessary evil of saving your health. I made sure my shop heater was big enough to recover from when I was pumping my warmth out the roof. A couple bucks in extra nat gas is well worth not getting sick from fumes.

[kdavis]

Thanks for the info-I will put it to use