Venting for welding station

[Mike99]

I do a lot of welding in my shop which creates mucho smoke. In the past ive just left the 2 garage doors open and turned on a fan but thats not fun in the winter. Im looking at rigging up a vent hood to a 4 inch duct and run it out the side of the shop. Does anyone know how many cfms the fan would need to be to **** out all the smoke? Thanks.

 

[R5P7Duster]

Following this.

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[sberry]

I made a booth for welding and welder training in cold weather, I also used it to evacuate a piece of galvanized a while back. Almost every piece was salvaged from washer and dryer, including the cabinet door and hinges.

 

[6768rogues]

Commercially they use a hood and exhaust fan, not a lot different from a commercial kitchen exhaust hood. You could fabricate a hood (considering that you weld your skills should handle that) or perhaps find a restaurant that is closing and make them an offer.

 

[TractorJeff]

Kitchen Exhaust Fan as I am not a production welder but a "Hobbiest".

 

[gorilla]

Commercially they use a hood and exhaust fan, not a lot different from a commercial kitchen exhaust hood. You could fabricate a hood (considering that you weld your skills should handle that) or perhaps find a restaurant that is closing and make them an offer.

This is not considered the best practice any longer. It's now considered best practice to extract fumes below the breathing zone with a smoke sucker of some sort. This is most important if you weld SST because of the hexevalient chromium given off when welding

 

[ssdave]

This is not considered the best practice any longer. It's now considered best practice to extract fumes below the breathing zone with a smoke sucker of some sort. This is most important if you weld SST because of the hexevalient chromium given off when welding

Agree. Extract the fumes at the work surface level, towards the back or downwards, away from the person welding. Baffle the work area so that the fresh air drawn in passes by the person, cooling them and drawing away fumes. An overhead hood draws the fumes upwards, past the person welding.

These are the type that are state of the art and used now instead of overhead hoods:

https://www.sentryair.com/weldingapp.htm

 

[Robby321]

I got a simple kitchen exhaust fan vented outside and works fine.

 

[lis2323]

I have the entry level Miller fume extractor and it works well.



Terry


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[6768rogues]

This is not considered the best practice any longer. It's now considered best practice to extract fumes below the breathing zone with a smoke sucker of some sort. This is most important if you weld SST because of the hexevalient chromium given off when welding

That could be correct. When I worked for the county they put in a welding instruction room at the local community college and had welding stations with steel benches, walls and hoods with exhaust fans. Perhaps the technology has changed since then.
Take a look at OSHA: https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10699
It essentially says that if you have a mechanical system it should be as close to the work as possible and that it will provide enough air changes to limit contaminates in the breathing zone to a safe level.
It seems that an exhaust hood that is suspended and connected to a flexible duct that could be moved near the work would be sufficient, as would ventilation through the side or back wall, or through the work surface. It is a performance spec, not a construction spec.

 

[Jbullfrog]

I have a drop from my shop's Harvey exhaust system over my welding bench.

 

[Lelandwelds]

Wow. Fume extraction in a home shop.

I suggest a diameter larger than 4" for your hose. I guess youre not using any filters? I suppose you are working only with small parts and are bringing all the work to one spot.

I like to heat the concrete where I am standing with an infrared propane heater. My usual problem is staying cool and drinking enough water.

 

[matt_i]

I worked once in a place that had a beautiful welding bench built of copper slats forming a table, which had the downdraft built into it. Nothing stuck to the copper plus it was all connected to be an excellent ground path. I don't know how you setup the actual draft other than to use a VFD or simple throttling valve, because I would think at some point you are sucking away the shielding gas. In a cold climate you'd also need to consider the makeup air, and I don't remember how that was handled, but you wouldn't want the booth to get super cold.

 

[kbs2244]

I have seen over the stove hoods used for bench style stations.

Some downdraft ideas may be gotten from kitchen BBQ grills.
They **** the BBQ smoke down and route it threw the basement to an outside wall.

 

[Lelandwelds]

An intake on the bigger side wont affect your shield much. Are you guys running stick or self shielded mig? S-6( or dual shield) doesnt smoke much. Tig or sub arc doesnt smoke at all. (Just kidding. I dont plan on 3 phase)

It would be pretty easy to weld up a straight tubing and shell heat exchanger for your make up air. https://www.comsol.com/blogs/how-model-shell-and-tube-heat-exchanger/

I wouldnt go crazy. Chain link top rail or EMT conduit and some single wall black stovepipe would work. No steam or HP here.

 

[Hot Rod Grampa]

If the space is heated or under air consider an air to air heat exchanger. A little more involved than a kitchen hood but it would scrub the heat/cool outgoing air and condition the incoming. The fan on the flexible duct to a filter system should be variable speed so you could dial it in just right instead of welding in a wind tunnel. Yes it's more work and $ but you only have one pair of lungs. Hope this helps.

 

[Thumper68]

I had made up plans for a nice smoke/fume/dust extractor for my welding table quite a few years ago then I realized that only about 50% of my welding was done in that locaton so I held off.

Then a few years later I moved my welding area, and again a few years after that I moved stuff around again.

Boy am I glad I never built it, now I am searching for a portable unit that I can take to the weld vs taking the weld to the unit.

 

[Thumper68]

Well I just got a portable fume extractor.

Lincoln Electric 120/240v in a online auction.

 

[apollo11]

I'd say just about anything is better than nothing

 

[Lelandwelds]

Its been a while but I used to rent the bigger extractors. We built a filter change each month into the rental rate. Expensive buggers.

I cant get over fume extractors in a home shop.

 

[Thumper68]

Its been a while but I used to rent the bigger extractors. We built a filter change each month into the rental rate. Expensive buggers.

I cant get over fume extractors in a home shop.

I don't know why this would be surprising to you?

A lot of the shops here are very well equipped.

I know my "Home shop is better equipped than many of the commercial shops I have seen or worked in.

 

[Lelandwelds]

In my former career, selling fume extractors was tough. Landing gas or consummable contracts was easy. Selling shiny new pulsed inverters or a shop full of plattens and the tooling for them was easy.

Fume extraction was the big push for a few years. Management was convinced metal fumes were the next tobacco or asbestos. I had a filler metal mfg pull out of the entire US market solely due to that fear. That cost me almost $400k in sales. I guess I still think about it on some level.

I had a few dozen customers with full air conditioned welding areas. I had customers with fume levels so high it was like an old school bar. I had black boogers after only spending 30 minutes on the shop floor. And, I had exactly two with full fume extractors . Tough sell.

Even tougher
Try selling disposable respirator to a maquiladora when each one costs more than the users wages.

 

[phy6]

If you need a portable unit, how about a shop vac rigged to a larger duct for intake, and route the output to corrugated drainage pipe/pvc/dryer vent tube out the door?

This made me consider installing a dryer vent in the exterior wall and having a more dedicated area for welding. An old bathroom squirrel cage fan or attic fan might work for a more permanent setup.

 

[Thumper68]

All the ones I have used over the years are high volume low flow, in other words they move a lot of air at slow speed so as to not pull the shielding gas away.

Shooting the fumes etc outside is great but you need to have make up air as well and in conditioned spaces this can add $$$ to the heating and cooling bills.

You could use a air to air heat exchanger to limit the cost but that adds more to the initial set up costs.

 

[bad_idea]

I work in ship repair. Fume extraction on a ship is fun. The best method is to **** it at the source. My preferred method is a smoke eater. Plugs into 110v, basically a shop vac with really good filters.

For use in the garage though, I plan to rig up a fan with a suction hose. Use the flexible ducting for a dryer for the hose. Put a filter across the outlet of the fan for catching dust (to keep it out of the yard). It's not rocket science, should be able to cobble something together cheap and effective. Just need to move the dirty air outside. Make up air? It's a home garage, not a production shop. Fab the whole works up on a cart w/ 20' of hose or so. Roll the fan outside, crack the garage door, and slide the hose under the door into the garage.

 

[bullnerd]

I plan on having a small system that exhausts outside and covers a few different locations in my shop.(bench/car work area) But I'm going have it remote to turn it on and off, and keep the remote on the mig machine. Turn it on until the air clears and then turn it off.

I don't understand the logic behind not be able to sell fume extractors therefore its not worth it to have one in a "Home" shop and protect our health the best we can.

 

[lis2323]

I don't know why this would be surprising to you?



A lot of the shops here are very well equipped.



I know my "Home shop is better equipped than many of the commercial shops I have seen or worked in.

I agree. I'm retired, but I'd like to live a little longer to enjoy puttering in my shop.



My entry level Miller fume extractor.

Terry

 

[nes999]

In my former career, selling fume extractors was tough. Landing gas or consummable contracts was easy. Selling shiny new pulsed inverters or a shop full of plattens and the tooling for them was easy.

Fume extraction was the big push for a few years. Management was convinced metal fumes were the next tobacco or asbestos. I had a filler metal mfg pull out of the entire US market solely due to that fear. That cost me almost $400k in sales. I guess I still think about it on some level.

I had a few dozen customers with full air conditioned welding areas. I had customers with fume levels so high it was like an old school bar. I had black boogers after only spending 30 minutes on the shop floor. And, I had exactly two with full fume extractors . Tough sell.

I totally believe it, I have spent years trying to talk my boss into a fine extractor. He won't have it. While we might weld 12-16 hours a day for weeks on end during the summer "We aren't a welding company so you are safe". Its amazing when the Hiliti van comes around how we have plenty justification for another over priced drill.



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[Thumper68]

I totally believe it, I have spent years trying to talk my boss into a fine extractor. He won't have it. While we might weld 12-16 hours a day for weeks on end during the summer "We aren't a welding company so you are safe". Its amazing when the Hiliti van comes around how we have plenty justification for another over priced drill.



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Thats easy to fix call OSHA, they will send a guy out to do a air quality check, then the boss will have no choice.

 

[Lelandwelds]

Motoretro

Why two similar bandsaws? Does your parts washer double as a pommel horse? Aren't you taking a chance on that floor? Without an epoxy floor the other guys might make fun of you.

Nice shop. I am beyond jealous. My toys were not as nice and I sold everything before the move. 600 sq ft of storage fees for 27 months wasnt worth it to me.

Nes999

You get it. I used to have to hear **** like " we don't sit to pee around here". and " poor baby. Is the big bad smoke upsetting your tum tum?".

Most companys have to see the OSHA boys only if they have 25 or 100 employees.

 

[MarkG]

I'm all for safety, but I always wondered about these things. If it's strong enough to pull smoke away, aren't you pulling your shielding gas away as well?

 

[Thumper68]

I'm all for safety, but I always wondered about these things. If it's strong enough to pull smoke away, aren't you pulling your shielding gas away as well?

No because you are moving a large volume of air at slow speeds.

 

[Lelandwelds]

It can but you have to work at screwing it up. Some big systems have several intake locations and variable speeds. Some have nozzles on the end of a hose. Nearly idiot proof.

Think of a big sawdust vacuum in a wood working shop. Picture opening every gate in the shop even idle machines. Picture opening just one gate.

They engineer for the middle scenario. Smoke doesnt weigh much. Pretty easy to **** it up. Shield gas only needs to cover the puddle and electrode and it comes out right THERE. Minor re positioning of your work, the pickup, or your off hand can fix little problems.

The filters are the expensive part. There's two or three of them to change out.

 

[isb cornbinder]

https://www.google.ca/search?q=mill...GAhMTWAhUVS2MKHSLEAowQsAQIWA&biw=1094&bih=522

Do yourself and your health a big favor and use proper ventilation. I am starting to suffer from early signs of emphysema and my welder Father suffered a slow death from emphysema brought on from years of breathing dust and fumes. Dad said he felt like he was drowning. Dad went from 6 foot 6 inch, 300 pound man to just barely tipping the scale at 125 pounds.
Dad died when he was 71. He would have been 101 this year.
Craigslist can be a good source of used vent machines.

 

[Dennis Leigh Henry]

Great project.. I had the chance to get a couple of commercial ones.. and didn't act on them.. dang...

 

[Lelandwelds]

I think if you rig up a squirrel cage and exhaust it away from view of traffic you will be ok. Just dont invite regulatory scrutiny. Cold climate might want a tube and shell or counter current heat exchanger built from scrap tubing. Might put in a diverter or damper to choose between downdraft table and hose for point-of-use http://www.instructables.com/id/How-to-Make-a-Plasma-Cutting-Station-DIY/

It would be easy to draft from the funnel for your scrap wagon.

 

[thunderskunk]

This is not considered the best practice any longer. It's now considered best practice to extract fumes below the breathing zone with a smoke sucker of some sort. This is most important if you weld SST because of the hexevalient chromium given off when welding

Extract fumes below the breathing zone… very interesting, sorry to dig up an old thread. I have some research to do.