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  • Dust collection?

    I have been thinking that it would be nice to add some decent dust collection to my shop. I'm not necessarily looking to build a big central system like some wood shops use, but something beyond throwing the stuff on the floor then shop-vacuuming it would be good. My shop is not tiny, but it's not that big either. When I do much grinding the dust gets around.

    I currently have a 2X72 belt grinder, a Darex, a typical bench grinder, and a T&C/surface grinder to service. None would be used at the same time and they are close together, so a moveable snorkel hose would be OK.

    The real issue is how does one avoid dust explosions from grinders in these sort of systems? It would seem there must be a way. Any thoughts? What do you guys do?

  • #2
    If you are grinding dry and producing dust you should have local extraction for the sake of your other machines if not your own lungs. Surface grinder is far better wet imho, belt grinder certainly a snorkel or hood, and bench grinder depends - if it's just touching up the odd drill point then the odd hoovering out with the shop vac. However if you are V grinding 1/2" plate for full penetration welding then something a bit more substantial is called for !

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    • #3
      What would be the source for the dust explosion? I've read of flour mill and granaries, sugar and cement plants having dust explosions, but never machine shops. A small Torrit system like a #64? would be good, fully isolated vacuum and collections areas, explosion proof motor, small enough to move around on wheels. I wouldn't trust a shop vac to last very long or be very safe with it's open universal motor.

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      • #4
        You could have a dust explosion from any flammable dust, the most likely in this situation would be wood dust from the belt grinder. I suppose that I could just avoid using it on wood, but it is just so darn handy that it seems a matter of time before someone does it.

        I suppose fine aluminum dust could be a problem as well, but I really have no feel how likely that is. It is entirely possible that I am over thinking this and overstating the danger. But as this is in my garage shop, I'd hate to find out by actually causing such an event(!).

        I am not thinking a grain elevator scale event that levels the shop, but maybe more a fire, etc.

        I have a decent industrial shop vacuum that does not mix the motor cooling air with the stuff it sucks up, so that helps a bit for general use. My understanding is that problems generally arise from sparks from grinding igniting stuff in the collection system.

        Just curious what's out there, this is no doubt a "problem" that has already been solved by many.

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        • #5
          "IN GENERAL", the dust concentration that poses an explosion hazard will be "visible".... You will be likely to say "gosh it sure is dusty in here".

          There may be dusts that are invisible in explosive concentration, but there needs to be enough dust that the burning of one particle ignites another several particles, and that requires them to be close enough together for that to happen.
          1601

          Keep eye on ball.
          Hashim Khan

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          • #6
            I use one of these: http://www.oneida-air.com/category.a...FSZo7Aodty4Adw

            I have a Ridgid shop vac as a vacuum source with a simple pipe system to the Dust Deputy. It will keep up with my 6 inch jointer, 12" bandsaw, and 10" radial arm saw. I have a wand for cleaning the floor up after using the 12" thickness planer.

            Pros use these for dustless floor sanding or drywalling- the ability of the DD to trap fine dusts is impressive: my shop vac is at least 5 years old and has never needed a filter- the inside is clean as the day it was new! I fill lawn and leaf bags with sawdust.

            Disclaimer: my nephew works for Oneida Air Systems.[IMG][/IMG]
            Last edited by CarlByrns; 11-02-2014, 03:27 PM.

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            • #7
              Never mix metal and wood dust and never use a wood dust collector for metal. Bad things can happen. Metal dust extractors are completely different beasts. I have seen chunks of built up steel dust cake catch and slowly smolder for a long period.

              Wood dust explosions can happen too. That is why most places use metal ducting and when plastic is used there is a bare copper wire running down the tube. In dry weather all it takes with high velocity air passing over plastic to build up a significant static charge. One unlucky discharge and it is all over with.

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              • #8
                Originally posted by macona View Post
                Never mix metal and wood dust and never use a wood dust collector for metal. Bad things can happen. Metal dust extractors are completely different beasts. I have seen chunks of built up steel dust cake catch and slowly smolder for a long period.

                Wood dust explosions can happen too. That is why most places use metal ducting and when plastic is used there is a bare copper wire running down the tube. In dry weather all it takes with high velocity air passing over plastic to build up a significant static charge. One unlucky discharge and it is all over with.
                For metal collection :http://www.oneida-air.com/inventory....-CAF1BB570002}

                The plastic Dust Deputy (and the vacuum hoses to the tool) is made from anti-static material and -here's the important part- there is no dust in the piping past the Dust Deputy- it's all clean air from the top of the cyclone. It really is that effective. No dust, no static, no boom.

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                • #9
                  When it comes to grinding and metal dust collection, my all-time favorite
                  solution is Gary Hart's "Grinding cart on wheels" as featured in post #374
                  of the "Shop Made Tools" thread.

                  Mr Hart's cart features a cyclone that draws from all the machines mounted
                  on the cart.

                  Originally posted by gary hart
                  There is a wealth of information about cyclone design/construction at
                  BillPentz.com
                  .

                  Alternatively, cyclone components can be purchased to make units like
                  that shown above by CarlByrns that mounts on top of a paint pail or this
                  unit of mine below (that is intended for a 45 gal drum)



                  Although, I have not adapted it to pull a draft on grinding equipment, this
                  Tepco unit intended for welding smoke could serve that purpose. The bottom
                  has a tray where gravity causes the heavy particles to separate. The mid
                  section has an electrostatic filter that captures the smaller particles, there
                  is provision above the e-filter for a 'paper' filter element. The upper section
                  of the cabinet houses the blower & motor. Air exhausts out the top.



                  Machines like these come up at auction from time to time and sell for very
                  little money. One MUCH nicer than mine looks in these photos sold here
                  two weeks ago for $150.

                  Another approach is to use units like these Single Inlet, Forward Curve,
                  Direct Drive Blowers from Dayton. The smaller one has a 1 HP turning
                  a 9" fan to produce 1390 CFM @ 1.5" static. The larger one has a
                  1-1/2 HP motor driving a 10-5/8 fan to produce 1850 CFM @ 1.5" static.



                  The fans pictured are from an automotive shop where they were fitted
                  with duct legs leading from several work stations: cyl head surfacing,
                  valve grinding and so on. These pulled from some distance and then
                  flung up their exhaust up and out vents in the roof. No provision for
                  collecting particles.

                  .

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                  • #10
                    I second the warning to not use a shop vac for a lot of dust pickup. Some cycle the air past the motor for cooling, and though that's after the filter I still wouldn't trust it. But I've never heard of any problem with fire or explosion, so -

                    Personally, my choice would be a typical motor powered impeller fan system with bags above and below, common in the woodworking industry. A 1 horse will go a long way although the more powerful ones do suck a lot more air through- and make more noise. They are bulky and take up floor space, so If I was to buy one for my own use in my home hobby shop, I'd be building it into a cabinet base somehow, so I could open a door in the base to remove the collections, yet still have the ability to filter the air leaving the system. Basically, I'd want just the motor/impeller/housing unit, and I'd build the rest of the system. The cabinet would do double duty as a stand for a workbench or maybe a machine.

                    At one time I did make a room air filter by wrapping a sheet around a sort of tall framework with a fan at one end. I used a relatively small fan- it was one of those stand fans that you buy to blow air around in the summer. I just got rid of all the parts that didn't suit the application, using just the motor and the fan basically. I would leave that run, and it would clean the air in my shop very noticeably. Now and then I'd bang it around a bit and dust would fall off the sheet onto the floor, from where I'd just sweep it up. This unit was about one foot square and maybe 4 feet high or so, but still it seemed to take up more floor space than I was willing to give. If there's any way you could, or would be willing to build a cabinet specifically to house a collection system, and where you'd be using the top for a workbench or whatever- I think that's probably going to be about the least intrusive in regards to using up floor space. Just my opinion.
                    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                    • #11
                      Originally posted by darryl View Post
                      I second the warning to not use a shop vac for a lot of dust pickup. Some cycle the air past the motor for cooling
                      No true shop vac uses intake air for motor cooling- they all have separate air circuits for vacuuming and motor cooling.

                      Cyclones are so much better at dust separation than filter media that it's not even arguable- they're the go-to in any industry where dust is an issue. Caterpillar uses them on their giant mine trucks- you can watch dirt and sand pour out of the bottom of the cyclone.

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                      • #12
                        I must investigate cyclone separation more thoroughly- I will need another system at work soon.
                        I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                        • #13
                          Just put a home-made Cyclone in the middle of the shop, and a shopvac outside.
                          Hardly any noise ( suction sounds mostly) , and very clean.
                          The shop vac filter (Sears in my case) goes 6 months before cleaning, as almost all dirt stays in the 20 gallon drum.
                          Solder a piece of 2 inch tube tangentially to the drum at the top.
                          On the center suction ( goes to the shop vac) attach a coffee can with no ends. This prevents dirt from entering suction pipe
                          and only air, as the refuse spins along the wall . add a metal flag below the coffee can to slow the dirt, which then drops to the bottom
                          When doing wet chips, pour sawdust on them first and let set for a few minutes before sucking up.
                          When sucking metal strings (chips w/o chip-breaker) have some 1 x 1 x 1 woodblocks and toss a few into the hose to break snares.
                          When my floor was poured, I buried a 2 "inch PVC pipe to supply the vacuum from the outside.
                          When you hear chips flying around, it means they are above the flag...time to empty the drum
                          System has been in operation 23 years and no plugs (!)
                          My previous shop had the suction pipe go to the ceiling and then outside ... That works too.

                          Rich
                          PS, The PVC can be slip fit and no glue needed



                          Last edited by Rich Carlstedt; 11-02-2014, 10:00 PM.

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