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  • vapour, fumes and particles: shop air quality

    been reading on some of the bad stuff we put in the air in the shop and how to avoid it....

    if I'm grinding carbide, cobalt (among other things) are released in the air as small particles - like fine dust, but they're still solid. If i wear the right mask while in the shop, presumably, like the next day, these solids have fallen out of the air across the shop and no longer are an airborne risk. much like wood dust i suppose (btw, everyone knows those so call dust collectors are nothing more than vacuums and do not protect your lungs, right?)

    however what about vapours. Cadmium when silver soldering for example. This is apparently a fume or gas....how then does it get removed from the air or does it? If I silver solder one day, wearing an appropriate filter, and then return the next, where are the fumes? still airborne waiting to get me?

    one answer is to vent, but that's a problem - all the warm air disappears....when's it safe to go back into the shop after releasing fumes (of the dangerous kind)

    so who knows about this an can help set me straight?
    .

  • #2
    I find that if I don't pay attention to my diet, I have a problem with fumes, vapors and particles that affect my shop air quality.



    Uh, sorry.
    Weston Bye - Author, The Mechatronist column, Digital Machinist magazine
    ~Practitioner of the Electromechanical Arts~

    Comment


    • #3
      The smallest particles do not settle. They can stay airborne almost indefinitely. Soldering and welding smoke eaters are pretty much mandatory in any good-sized shop. I do wood and metal. Got a 1200 CFM electrostatic cleaner that does the whole shop and a 3 HP 3000 CFM commercial cyclone for the wood. Not a trivial thing to do. Takes a lot of airflow to suck dust at any distance from the inlet. Small shop, maybe you can get away with 3 HP. Most people totally undersize home shop systems. Power requirements go up exponentially with size. Small commercial shops, looking at more in the 50 HP range. Look at the Bill Pentz website. Deals with wood mostly. All kinds of issues. Fire safety, health, cost. Not supposed to use the wood system for metalwork. I have shop vacs, which is very marginal. They will not catch the micron-sized particles that are the problem. They get the bigger dust, but not all of it. For a price, you can get mini-cyclones that will work. I use the electrostatic and hope for the best.

      I just filter and recycle to save on heating. Fire codes for any decent system require the cyclone to be outside. Then you need heat exchangers and it gets complex quickly. If you're concerned, and it isn't a bad thing to be concerned about, look into one of the mini-cyclones. Oneida makes some. Not cheap.

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      • #4
        I do anything that generates nasty fumes outside.

        - Bart
        Bart Smaalders
        http://smaalders.net/barts

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        • #5
          I do anything that generates nasty fumes outside.
          says the guy from CA

          Bob, I've read alot of Bill Pentz website. He's convinced me that the average wood worker buying a cloth bag collector and thinking he's protecting himself is a real problem....one day one of the manufacturers will get sued and it'll be the end of the cloth baggers. The limited woodworking i do is with hand tools and don't think sandpaper has any place with wood so my issues are more focused on metal working and fumes. if into machining wood, the dust collector, like say a Felder, might be the most expensive piece of equipment you need to buy....either that or wear a mask and let the electrostatic cleaner do its thing over night.

          Originally posted by Just Bob Again
          The smallest particles do not settle. They can stay airborne almost indefinitely. Soldering and welding smoke eaters are pretty much mandatory in any good-sized shop. I do wood and metal. Got a 1200 CFM electrostatic cleaner that does the whole shop .
          So a electrostatic cleaner will do the job on say solvent fumes or cadmium fumes? By do the job I mean if i wear a charcoal mask while doing the work, will it be cleaned up in say 24 hours. Is this similar to the furnace cleaners? I though they zapped larger particles.....but a fume is a gas so we're talking individual atoms/molecules right? ie they have no shear strength, they are a fluid...can an electrostatic cleaner remove them?
          .

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          • #6
            Welding hood or fume extractor, vents outside ....along
            with the nice heated air drawn from the rest of the shop.
            My own contribution to global warming, which is not working
            too well, it was about -5F again this am here in Michigan.
            Hate to see the power bill this month.
            Dave P.

            Comment


            • #7
              I've been thinking of plumbing in a vapor/smoke collector network to all my benches and machines just running the exhaust outside. This won't be for solids mind you, welding and soldering fumes/smoke, cutting oil smoke and the like. What kind of cfm should I be looking at, and how large a tube? I was thinking of using 3" metal dust collector parts and a squirrel cage fan. Maybe necking down to 2" at my drops and just use commonly available shop vac hoses.
              James Kilroy

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              • #8
                I am going to watch this topic. I do a lot of carbide grinding with diamond. I have a vacuum on my grinder with a bag designed for drywall dust. The discharge goes through the wall and out side. If I blow my nose after grinding I still have black crap I have breathed in. I wear a respirator-sometimes. I am at a loss as to what to do next. I am sure there are many people in various industries with lung damage caused by inhaled toxins. Can it be totally avoided? I often think it is probably just as dangerous walking down the street inhaling auto exhaust.

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                • #9
                  I've got 6 in hose to the collectors, sorry I don't know
                  the CFMs on the blowers.
                  Keep in mind for welding you don't want a fast moving
                  draft screwing up the gas coverage. I'm thinking volumn
                  more than velocity.
                  Dave P.

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                  • #10
                    Electrostatic Dust filters

                    While working at the university, I purchased two "Smokemaster" electrostatic units for our shop. I was amazed at how much fine dust they took out of the air. I would service the units every three months by removing the cells, which were aluminum cages filled with fins and isolated tungsten wires, rinsing them in a detergent bath, and then rinsing them in the shop shower. The water that came out of them was black as truck stop coffee. We had one over the welding bench and it would suck up all the fumes and smoke and blow out clear air. The units were designed to be used in places like bowling alleys and bars, where there would be a lot of cigarette smoke. I was impressed with how much cleaner the shop was. It stopped the buildup of grey dust that accumulated in corners and around the handles of your tool box. I wish we had bought them years earlier.
                    Jim (KB4IVH)

                    Only fools abuse their tools.

                    Comment


                    • #11
                      Originally posted by Mcgyver
                      So a electrostatic cleaner will do the job on say solvent fumes or cadmium fumes? By do the job I mean if i wear a charcoal mask while doing the work, will it be cleaned up in say 24 hours. Is this similar to the furnace cleaners? I though they zapped larger particles.....but a fume is a gas so we're talking individual atoms/molecules right? ie they have no shear strength, they are a fluid...can an electrostatic cleaner remove them?
                      If you're working with cadmium-bearing silver solders or other sources of cadmium fumes, be careful. Occupational exposure limits are very low
                      (5 ug/m^3); the stuff is just plain nasty and bio-accumulates. Metal fumes go down to .5 micron particle sizes, so HEPA filters (99.97% removal at .3 microns) are needed to remove them.

                      http://www.osha.gov/Publications/313...3-English.html
                      Bart Smaalders
                      http://smaalders.net/barts

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                      • #12
                        You can always grind carbide etc WET with a slow-speed grinder. That tends not to make much airborne dust.
                        1601

                        Keep eye on ball.
                        Hashim Khan

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                        • #13
                          Originally posted by J Tiers
                          You can always grind carbide etc WET with a slow-speed grinder. That tends not to make much airborne dust.
                          Yep. But I have a customer that has done this on a production basis for over 30 years (some of the grinder control systems I built for him are nearly that old). The mist that comes off the machines has formed a film on everything in the shop. Everything feels sticky.
                          Weston Bye - Author, The Mechatronist column, Digital Machinist magazine
                          ~Practitioner of the Electromechanical Arts~

                          Comment


                          • #14
                            What about an air to air heat exchanger?A turbo intercooler off a large truck would do the job.Feed the blowers exhaust through the intercooler which would be in cased in an insulated box.Through that box would have to pass the return air from outdoors.Aluminum construction and many thousand square inches of surface area would transfer heat nicely.

                            Like this,but bigger,a heavy truck wrecking yard usually has several damaged units laying around that can be had for scrap aluminum price.

                            http://en.wikipedia.org/wiki/File:Ic-extrior.jpg
                            I just need one more tool,just one!

                            Comment


                            • #15
                              Originally posted by Just Bob Again
                              The smallest particles do not settle. They can stay airborne almost indefinitely. Soldering and welding smoke eaters are pretty much mandatory in any good-sized shop.
                              Wow, I'm going to die.

                              How much do these electrostatic filters run?
                              "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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