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chopsaw discs for Alumin(i)um ??

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  • chopsaw discs for Alumin(i)um ??

    Hey Folks, wondering what kind of "bad things" will happen to me if i use a regular steel cutting disc to cut Al on the chopsaw?? I know they make discs specifically for non-ferrous metals but they're about 6x the price of the regular makita ferrous types....i've used these things on worksites for both and never given it much thought....now i'm kind of curious....thanks!

    Chris

  • #2
    Careful what you do there Chris.

    <font face="Verdana, Arial" size="2">
    Do not mix aluminum grinding dust and iron or steel grinding dust. Such a mixture
    can, under special conditions, explode. Finely divided aluminum mixed with
    finely divided ferrous oxide forms thermite, a compound that burns at greater than
    3000C.</font>
    http://www.jlab.org/ehs/manual/PDF/6...ngGrinding.pdf

    http://www.hanford.gov/lessons/sitell/ll01/2001-36.htm
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    • #3
      An abrasive type saw won't work on aluminum. The aluminum will just smear. You might have better luck with a carbide tipped wood or non-ferrous metal saw, but you have to watch the diameter of the material being cut. I ruined a brand new $50.00 non-ferrous carbide saw blade on the first cut when I tried to use my miter saw to cut through a peice of 4" wide 6061 T6. If you do try it, make sure the peice is in a vise, don't try it by hand. I've heard that a table saw is better for cutting aluminum, but I won't chance ruining my table saw. Personally, I'm going to get one of those little metal cutting band saws from Harbor Freight.

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      • #4
        I use an 80 tooth, 12", carbide, "non-ferrous cutting" blade in a chop saw that I purchased from DeWalt. If I remember? It wasn't too awfully expensive.
        If you have a lot of cutting to do or in production, this is the way to go... fast with very nice cuts (Protect your ears! it screams). Using a vice to hold the material is an absolute must.

        For a home shop with an occasional cut, it's hard to beat a bandsaw. Start the cut and go have a beer.

        There is a Yahoo group, "4x6bandsaw" where the guys like to modify and fine tune their saws.

        I often have to cut aluminum bar 1/8" x 4". I do these on my table saw, using my regular Carbide wood cutting blade. This works really nice also. The chips can be hot.

        Tom M.

        [This message has been edited by mayfieldtm (edited 06-01-2005).]

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        • #5

          I have two table saws, both rickety old Craftsmans. One was given to me by the guy next door. The other I bought real cheap. One is loaded with and abrasive disk, and I use it to cut ferrous stuff. The other has a carbide-tipped blade with fairly fine pitched teeth. I use the carbide to cut aluminum. I use the guide so I cut in a straight line - otherwise, I'm afraid it would kick or bind. It makes a hell of a noise, and chips fly everywhere. I wear a welding helmet with the tinted glass tilted up, and good ear protection. Later I use a shop vac to get all the chips up.

          I've cut aluminum 2-3" thick this way. The cuts are not perfect and I have to comb chips out of my hair, but it works. I normally use this method to cut off a bit of aluminum to work on the mill.

          I know about thermite, and I'm careful where the chips go. Other than that, it seems to work. If there's anything dangerous about this, someone please let me know. (Other than the normal dangers of a table saw).

          -M
          The curse of having precise measuring tools is being able to actually see how imperfect everything is.

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          • #6
            The 12-14" carbide blade idea works good,SO LONG AS you get one with many teeth,80 or better as mentioned above.
            Do not use a blade with less teeth,don't use any without a little lube or coolmist.
            I found out the hard way,I used a 25 tooth in my chopsaw to cut some 2x2x1/4 aluminum angle,on the third cut one tooth gullet loaded up and the whole tooth came out with a bang and bent three more over next to it.
            Nothing but the blade got hurt thank God,but it could have been worse.
            I just need one more tool,just one!

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            • #7
              "Do not mix aluminum grinding dust and iron or steel grinding dust. Such a mixture
              can, under special conditions, explode. Finely divided aluminum mixed with
              finely divided ferrous oxide forms thermite, a compound that burns at greater than
              3000C."

              Is this something to consider when using a small - 4 x 6" - bandsaw?

              The bandsaw is run dry, no cutting fluid used, but I do alternate cold/hot rolled and aluminum cutting with a piece of brass occasionally thrown in.

              [This message has been edited by C9 (edited 06-02-2005).]
              C9

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              • #8
                I use Forrest blades on my cabinet saw. I once asked the guy about cutting aluminum and he said they have a special 80tooth blade with a differant rake angle just for aluminum.

                they are at http://www.forrestblades.com/ and list a 1-800 number on the site. I have about 6 of their wood blades and they make a great product, quiet running and very good carbide.
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                • #9
                  C9,

                  I wouldn't worry about bandsaw filings. They aren't fine enough. I have experimented with igniting them (aluminum) and it doesn't happen even if you throw a handful in a bonfire. But, the dust from grinding and especially sanding is a different matter. It can cause a thermite reaction with iron oxide. This also isn't a problem on the band saw since the iron chips aren't oxidised. The iron powder that comes off a grinder or cutoff saw is oxidised and when mixed with the really fine aluminum powder can possibly result in a thermite fire.
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                  • #10
                    Thanks Evan.

                    Seems like it's the stuff you don't know that gets you.

                    C9

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                    • #11
                      We've had this 'thermite discussion' here numerous times. And I don't remember any of us, who have tried to intentionally create the proper mix, did so successfully. I know I haven't, and I've tried many times.

                      I think the problem is that it needs, not powdered aluminum dust, such as would come off a saw, but rather finely powdered aluminum oxide.

                      [This message has been edited by lynnl (edited 06-03-2005).]

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                      • #12
                        Nope, it requires powdered aluminum and iron oxide, not aluminum oxide. The aluminum is the fuel, the iron oxide is the oxidizer.

                        From a MSDS for aluminum flakes:

                        <font face="Verdana, Arial" size="2">

                        CONDITIONS TO AVOID

                        ...
                        Iron Oxide (rust) and other metal oxides (e.g. copper and lead oxides): A
                        violent thermite reaction generating considerable heat can occur. Reaction with
                        aluminum fines and dusts requires only very weak ignition sources for initiation.
                        Molten aluminum can react violently with iron oxide without external ignition
                        source.

                        </font>
                        http://www.transmet.com/PDF%20Files/EuropeanMSDS.pdf
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                        • #13
                          thanks for all the advice guys !! appreciate it !

                          Chris

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