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  • Grinding wheel explosion ?

    Have read the following and considering the contents strange (though had to cosider the source as very serious indeed) am asking if you know anything about it.

    George.

    Aviation Electronics
    Technician - Basic
    NAVEDTRA 14028

    • Jun 1991: Original edition released.
    • Mar 2003: Minor revision released.

    NEVER use the grinding wheel on
    nonferrous metals. When used with this
    type of material, the grinding wheel could,
    in effect, explode.
    . This could result in a
    serious injury to or death of personnel.

    Published by
    NAVAL EDUCATION AND TRAINING
    PROFESSIONAL DEVELOPMENT
    AND TECHNOLOGY CENTER

    Page 7-10
    Last edited by GeorgePapa; 12-24-2009, 05:50 PM.

  • #2
    Well, they CAN load up to the point where they can blow up on you. The trick is to dress the wheel often to avoid loading it up. I've ground non-ferrous material numerous times over the years with standard grinding wheel with no problems other than excessive heat build-up. Dress the wheel often,use coolant, and oh, did I say? Dress the wheel often.

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    • #3
      I don't know if they explode, they do become unbalanced and have a catastrophic failure while rotating at high speeds. The use of ferrous grinding wheels for non ferrous materials is a non brainer as the become clogged and destroy themselves sooner or later. The aluminum becomes wedged in between the openings of the grit et all
      more than most would want to know
      Glen
      Been there, probably broke it, doing that!
      I am not a lawyer, and never played one on TV!
      All the usual and standard disclaimers apply. Do not try this at home, use only as directed, No warranties express or implied, for the intended use or the suggested uses, Wear safety glasses, closed course, professionals only

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      • #4
        When I was in high school in the '80s , we had a individual try to shortcut on a foundry project by finishing a aluminum part on the grinder , when the teacher stepped out for a moment,( we were told to file the part to finish it)Just as the teacher returned, the wheel let go , missing the student and knocked a big chunk out of the cinderblock wall... needles to say that was a new saftey talk at the beginning of every simester.....

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        • #5
          Intresting, I have heard of this before..
          And iv also seen my (usally more intelligent) brothers grinder completely and utterly loaded with aluminum.. and another time with wood... you could hardly SEE the wheel anymore it was so badly loaded.. I think he blamed the wood on his wife, but I think the aluminum was him -_-;
          I even GAVE him a diamond wheel dresser.. and asked him every time I saw him for 4 months if he had used it... Never did get a 'yes' -_-;
          Hes a 'professional' welder too.. And has allready had a 4.5" angle grinder wheel blow up in his face when he was new on a job.. (Don't trust your coworkers NOT to put a 10,000rpm wheel on a 20,000rpm high speed sander to give to the new guy!)

          Also heard of aluminum dust + corroded iron dust (iron oxide) + grinder sparks = thermite going KABOOM.
          Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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          • #6
            I saw a wheel on a toolpost grinder let go. It took big chunks out of a wooden door.

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            • #7
              I've ground aluminum plate on a surface grinder.
              I used WD-40 for lube, and dressed the wheel after every 3rd pass across the part.
              No problems.

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              • #8
                Yes, you can grind Aluminum with the PROPER wheel. Anybody seen Blanchard ground Aluminum tooling plate?
                Norton wheel:
                http://www.northerntool.com/webapp/w...2113_200332113

                But they are hard to find.

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                • #9
                  I'd want to know more about what kind of wheel they are talking about. What abrasive? What bond?

                  Norton says to use their black silicon carbide wheels on Aluminum.

                  Originally posted by Jack772
                  I saw a wheel on a toolpost grinder let go. It took big chunks out of a wooden door.
                  I saw a toolpost grinder wheel explode, and part of it took out a window behind the lathe, part of it bounced off the lathe carriage and went up and took out a flourescent light, and part of the wheel hit my friend just below the belt and knocked him onto his a$$. Of course, we didn't report the injury...he was working on a home project for me at the time.

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                  • #10
                    One of the best things I put in the shop was a big belt grinder.

                    Safe for aluminum.

                    Takes the strange grinding projects away from the well dressed conventional grinding wheels on the bench grinders, and reduces the grinding wheel dressing!

                    Belts run pretty clean, and I use a big rubber belt cleaner when they get a little clogged from aluminum.

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                    • #11
                      To SC or not to SC - that is the question.

                      Originally posted by john hobdeclipe
                      I'd want to know more about what kind of wheel they are talking about. What abrasive? What bond?

                      Norton says to use their black silicon carbide wheels on Aluminum. ,................................................

                      .
                      Yep that's so. Same does/goes for pretty well most non-ferrous stuff that needs to be ground.

                      Same applies to TC tips/inserts too if you don't have a diamond or cubic boron wheel or the Norton "Hard" ("blue") wheel as silicon carbide wheels will do it at a pinch.

                      The most likely cause is abuse such as when a wheel will not "ring" properly.

                      Clogging (-up) and poor balance and poor dressing don't help much either.

                      There is far too much "urban myth" and "boogie-man" stuff about as regards grinding wheels.

                      More faults can be traced back to the operator than to the machine or the wheel.

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                      • #12
                        There is a lot of "it depends" in this question. In particular it depends on what sort of aluminum you want to grind. Aluminum and it's alloys go all the way from 6000 psi to over 100,000 psi in ultimate yield strength and from soft-as-warm-butter-dent-it-with-your-teeth to harder than mild steel.

                        Pure dead soft electrical aluminum will clog up any wheel faster than a Big Mac clogs your arteries. 7075 T-6 grinds more like steel and the swarf can make tiny needles. If you do need to grind aluminum on a regular wheel touch the wheel with a wax stick first. It will help to prevent loading. Don't use oil though. While it won't hurt a vitrified wheel it can cause failure of some resin bonded wheels depending on the resin type.

                        As far as making a wheel explode just because it was touched with aluminum, no.

                        Also heard of aluminum dust + corroded iron dust (iron oxide) + grinder sparks = thermite going KABOOM.
                        While the apocryphal Thermite Reaction does exist it is a lot harder to make it happen in practice than some urban legends would have you believe. I tested this particular "almost myth" and there is no way I could get any sort of response from aluminum dust from my belt sander mixed with oxidised steel from the wheel grinder. It made no difference what ratio I used or how hot I made it. No thermite, none. To make thermite you need aluminum powder and FeO3. FeO3 is Hematite while the result of burning iron in air makes a combination of unburned iron, FeO and FeO2 fume. There isn't enough oxygen in the dust from grinding iron to promote a thermite reaction.
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                        • #13
                          I thought the hazard increased if the iron rusted. That is, rusted iron powder intermingled with ally powder could produce a hell fire inferno that you can't put out. I haven't looked at the chemical makeup - just one of the things you hear in the rumor mill.

                          I know that in my yoot I could energize a number of exotic combustibles with various powdered metals - copper being a rather colorful one. The chemlab at BHS had some fun stuff

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                          • #14
                            One of the biggest problems is the aluminum. It's flammable even in air but only if enough surface area is exposed. I tried that experiment too. I collected a large bag of aluminum fines from my belt sander and tried tossing handfuls in a bonfire. It barely even sparkled just slightly. Mostly nothing at all happened, the powder wan't fine enough.

                            IF you could make it fine enough AND the iron fines had formed FeO3 from exposure to water after grinding THEN you might be able to produce a thermite reaction.

                            What I have seen happen is fine iron powder catch fire in a very controlled manner. It glows red hot and the combustion is slow and stable, very easy to douse with some water. This is about the same as you will have if you light a wad of fine steel wool with a match.
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                            • #15
                              What makes everyone beleive they are discussing Surface Grinding Wheels or even Bench Grinding wheels in this article ?

                              Being the advisory was directed to "Aviation Electronics Technician" I would have thought they were discussing 4.5" peanut grinder cut off wheels

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