Exhaust Fan For Welding

[MadeByMiller]

My shop is a small single car detached garage. I run my welding and fabrication business from it, and I spend every day welding and grinding inside. I wear a respirator at all times, but I would like a way of extracting the fumes still. When it's nice I always have the doors open to ventilate the shop, but I'm planning on soon insulating and climate controlling the building and obviously still need some ventilation. I've seen people use a simple exhaust fan in the wall to pull out the fumes, but I'm concerned it will pull out my warm air in the winter and cool air in the summer. Is there a better solution? I'm aware of the stand alone fume extractors made just for welding, but they are quite large, and every inch of space counts in my little shop. I'll attach a picture of the style of exhaust fan I've seen people use, in much larger shops than mine.

 

[bdbecker]

Have you considered a ceiling mount air cleaner that filters and recirculates the air? Something similar to this:
https://www.grizzly.com/products/Shop-Fox-3-Speed-Air-Filter/W1690

Not "weld specific" but would do a pretty decent job of helping to clean up the ambient air without pumping it outside.

 

[MadeByMiller]

Have you considered a ceiling mount air cleaner that filters and recirculates the air? Something similar to this:
https://www.grizzly.com/products/Shop-Fox-3-Speed-Air-Filter/W1690

Not "weld specific" but would do a pretty decent job of helping to clean up the ambient air without pumping it outside.

Thank you for bringing those up! I have thought about them, it seems like a lot of woodworkers like them. I would love to hear from other welders/metalworkers to see how effective they are in this environment. I'm also aware that welding, especially certain metals, produces chemicals in the air that are generally not removed by most filtration systems. My thought was that exhausting the air from the shop would potentially remove these chemicals from the confined shop.

 

[maxpat82]

Any air exhausted will be replaced by outside air ...so yes you will loose heat and cooling.
But it's still way better then working in a fumed out shop!

 

[strutaeng]

I don't think those woodworking air cleaners would work for welding fumes. Welding fumes are mostly smoke, so tiny, tiny particles, I bet much smaller than wood dust.

At my old house I had a 2 car garage and installed a similar fan. It didn't work too well, as smoke from welding always lingered for about 5-10 minutes after I stopped welding. It was this unit: https://www.rewci.com/10-inch-shutter-fan-with-cord.html

Maybe go with a larger fan unit, but if you are running a business why not invest in a fume extractor actually made for this purpose? Maybe cost?

Another thing to consider is ventless kitchen exhaust hood with those activated charcoal filters. In theory it would eliminate smoke, but don't know how well.

 

[MadeByMiller]

Any air exhausted will be replaced by outside air ...so yes you will loose heat and cooling.
But it's still way better then working in a fumed out shop!

In theory I guess I knew that, I thought maybe some options for ventilation would be better than others.

I don't think those woodworking air cleaners would work for welding fumes. Welding fumes are mostly smoke, so tiny, tiny particles, I bet much smaller than wood dust.

At my old house I had a 2 car garage and installed a similar fan. It didn't work too well, as smoke from welding always lingered for about 5-10 minutes after I stopped welding. It was this unit: https://www.rewci.com/10-inch-shutter-fan-with-cord.html

Maybe go with a larger fan unit, but if you are running a business why not invest in a fume extractor actually made for this purpose? Maybe cost?

Another thing to consider is ventless kitchen exhaust hood with those activated charcoal filters. In theory it would eliminate smoke, but don't know how well.

Glad to have your input. I think you're right on the air cleaner bit. On the welding fume extractors, I mentioned in the initial post that I have a really small shop, and those fume extractors are pretty massive. I don't want to have to sacrifice that much floor space. Interesting idea with the kitchen hood, I'll look into it.

 

[maxpat82]

I have a fan that look like an HVAC fan(squirrel cage) with a 10" exit and is capable of 1200cfm....it work great.

I have made an adapter for a 6" hose and place it near my welding table on the ground.......the majority of fume is quickly extracted outside

 

[sberry]

Put a box fan or even a twin insert window fan in a window on one end of the building and crack the walk door or another window in the other end and **** air out. Could even integrate some hood scheme for some of it. If you insulate this small garage wont take lots to recharge some heat, aint gotta have it going full blast all the time and can even regulate the draw with the intake some. Sealing the room up somewhat tight and controlling the intake and can gather the fumes up in an orderly fashion and **** them out.

 

[bdbecker]

I don't think those woodworking air cleaners would work for welding fumes. Welding fumes are mostly smoke, so tiny, tiny particles, I bet much smaller than wood dust...

You are correct, one of those units would not capture all of the particles found in weld fumes, but it would capture a fair amount including the grinding dust he mentioned.

Different scenarios require different solutions. If the OP is doing a multiple hours of stainless steel production welding every day, evacuating the air from his shop would probably be the best course of action because trying to filter sub-micron hexavalent chromium particles is probably not practical for a small shop like his. However, if he doing fab/fit-up/repair type work on carbon steel where the arc on time throughout the day is measured in minutes instead of hours, one of those scrubbers may be more than adequate to keeping the particulate concentration within acceptable levels. It all depends on the OP's needs - I simply suggested that filter system as an option, not necessarily the solution.

 

[MadeByMiller]

You are correct, one of those units would not capture all of the particles found in weld fumes, but it would capture a fair amount including the grinding dust he mentioned.

Different scenarios require different solutions. If the OP is doing a multiple hours of stainless steel production welding every day, evacuating the air from his shop would probably be the best course of action because trying to filter sub-micron hexavalent chromium particles is probably not practical for a small shop like his. However, if he doing fab/fit-up/repair type work on carbon steel where the arc on time throughout the day is measured in minutes instead of hours, one of those scrubbers may be more than adequate to keeping the particulate concentration within acceptable levels. It all depends on the OP's needs - I simply suggested that filter system as an option, not necessarily the solution.

Maybe it would work well in tandem with fume extraction as well, for the grinding dust like you said. I do TIG weld some stainless, but the bulk of my work is on mild steel. Most days I'm welding constantly throughout a 12-15 hour day. I'll do some digging around on the web and see if anyone has experience using one of those air scrubbers in a similar environment.

I really appreciate all of the discussion guys!

 

[bdbecker]

Assuming a 25% arc on time, that's 3-4 hours a day of fume generation - IMO you would definitely want a filtration system that's designed for welding applications at that point. Given your space constraints, I'd probably focus on extraction. Perhaps a hood or duct for your main bench area, and a whole shop unit like you have in your first post. That way if you are doing something small at your bench all day, you can pull a smaller amount of air out of your space using the hood/duct and spend less energy on heating/cooling the space. When you get crazy on a big project, turn on the big fan and **** all that air out.

Given this info, when it comes to choosing a heating system for your shop. I'd lean towards an infrared radiant heat system instead of convection (heated air) system. Heat the objects, not the air. Then you can run the big fan and still keep you (and your material) warm.

 

[MadeByMiller]

Has anyone used an HRV (Heat Recovery Ventilation) system to exchange the air in their shop? This seems like the best of both worlds, exhaust the fumes while warming up the intake air.

 

[texasprd]

Has anyone used an HRV (Heat Recovery Ventilation) system to exchange the air in their shop? This seems like the best of both worlds, exhaust the fumes while warming up the intake air.

That was going to be my suggestion too, if the OP can afford it