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  • Another Mystery Metal Question

    I finally put together a O/A welding/cutting rig. Tried to do a little brazing, just for practice, on a piece of metal that once was part of computer chassis. This stuff is about .070 thick and has some sort of anodized coating (gold) on it. The result could best be described as a catastophe. I had similar results a few years ago when I tried MIg'ing some of the same stuff after I bought my little Mig outfit. The logical conclusion that one would jump to of course, is that the coating is causing the problem. But it is equally repellant to brazing rod or a mig bead after grinding away the coating.
    Anybody have an idea as to what this stuff might be? It's magnetic. Grinding sparks seem to sparkle more than regular mild steel, but not quite so much as say, a file. A file will cut it ok, but it sure seems hard.
    As stated, I'm just using it for practice, so it's no major deal, but I welcome any thoughts or inputs from the collective wisdom of this group.


    Lynn (Huntsville, AL)

  • #2
    The gold stuff is either cadnium plating or yellow zinc chromate,don't breathe the fumes from either.

    The base metal is just carbon steel sheet modified with silicon and sulpher to make it easy to punch and form as I remember and is difficult to weld.

    A good cleaning to remove the plating and it will silver solder nicely. It will also resistance weld good.
    I just need one more tool,just one!

    Comment


    • #3
      Why don't you try your welding on a known metal, like some mild steel and see if you can braze that. Then work up to the more difficult (mystery) stuff????
      _____________________________________________

      I would rather have tools that I never use, than not have a tool I need.
      Oregon Coast

      Comment


      • #4
        lynnl, I was not trying to be smart but now days you never know what kind of coating or plating you'll come up against. I've been using O/A for 50 years and still find times when I can't make a good weld. play with the O to A ratio and enjoy!!
        _____________________________________________

        I would rather have tools that I never use, than not have a tool I need.
        Oregon Coast

        Comment


        • #5
          Lynn

          Avoid the ZInc Dichromate and Cadnium plating in paticular. Cadnium is consider very toxic and normal practice is to WaSH YOUR HANDS immediately after handling this hardware (common on grade 8 plated hardware) and do not eat or drink before doing so. It is a good idea if you grind metal with this crap on it to wear a mask rated for metal particulates as well. DO NOT WELD IT - Toxic fumes are BAD for you! While you are at it do not weld galvinzed (hot dipped, plated, or flashed) metal either.

          Same goes for Berillium if you come across it.

          Comment


          • #6
            lynn...I used to do a lot of gas welding. I had the same problems sometimes when welding weird stuff. I think what it all boils down to is the procees. It is so much slower and the HAZ (heat affected zone) is so much greater that impurities will migrate from a long ways away inot the weld puddle. You can find the same problem with Tig sometimes when welding at low amperage/speed. It suprised me to find out how far away I had to start cleaning the metal before the problem was solved. And..yes..watch out for that weird stuff when gas welding! I welded something one time (too dumb to quit)that ended up giving me horrible nose bleeds for a couple days. So beware! Another thing...proper gas welding rod in the lower numbers isn't "killed" as well as the higher numbers and can cause crappy looking welds. Want a crappy weld...try tigging with RG45...want to make it nicer...use RG 60. Heh heh...I used coat hangers many times! The old ones worked very well. Don't know about the newer ones!
            Russ
            I have tools I don't even know I own...

            Comment


            • #7
              Hey Thrud ! If all that stuff is as bad as they say, how come we're all still around? Den

              Comment


              • #8
                Thanks all.
                Cadmium had crossed my mind, but it didn't look exactly like the plating I've seen on cad plated nuts and bolts. At any rate I was doing it on the outside in fresh air, and I try to make a practice of not breathing fumes or smoke of any kind.
                But this does raise a question I've wondered. I know lead and mercury accumulates in the body. Is that true of all other metals, such as cadmium and chromium as well?

                Lugnut, you certainly make a valid point about learning on some known material. My problem was that all my handy sheet mild steel pieces are already covered with practice beads. I probably should toss them or grind them off, if for no other reason than to destroy all the embarassing evidence.
                Lynn (Huntsville, AL)

                Comment


                • #9
                  Any newish piece of metal should not have cad plating. IIRC, that is a no-no these days per EPA.

                  Most likely it is the chromate.

                  That said, out of china, who knows. They have no safety rules, and less enforcement.

                  We were at K-mart only a few years ago looking for Christmas toys for the nephews. I saw that they had one of those little plastic maze toys that you tilt and get the little balls to roll thru the maze.
                  Problem is, what was in there was a blob of MERCURY .
                  I hustled up to the service desk and mentioned that, where the manager assured me it was only "colored water"....right....
                  But I noticed it wasn't there when we came back........

                  Point being I suppose that it still COULD be cadmium, but I doubt it, frankly. Not that chromate is good stuff....
                  1601

                  Keep eye on ball.
                  Hashim Khan

                  Comment


                  • #10
                    JTier, how new is 'newish'?
                    This stuff I have was probably mfg'd in the early to mid 80's.
                    When tilted in the light just right it gives off a kind of phosphorescent sheen. Something like those laser images you see on such as credit cards. (..can't think of proper terminology at the moment)
                    The surface texture of the metal itself almost looks like it has been rough ground.
                    Lynn (Huntsville, AL)

                    Comment


                    • #11
                      You would have to ask.....and I don't have a date for it. I would reckon on mid 90's, but as I said, with chinese goods you have no idea what's in them.
                      1601

                      Keep eye on ball.
                      Hashim Khan

                      Comment


                      • #12
                        I used to work for several die stamping houses that did contract stampings for many of the major computer mfgs. Without knowing the exact type of steel it was always something inexpensive and easily worked that would go out for plating/coating after coming out of the press. I would agree with the others in that it's probably something that you don't want to inhale/ingest and would suggest finding something else laying around to make puddles with. Wish I had such a rig as you as that would open up many more possibilities.

                        Comment


                        • #13
                          Den
                          For the same reason I keep telling my Doctor to give me his Mercury BP meters and buy electronic ones - the cheap bastard. I am just trying to get free stuff and resell the really expensive mercury at a massive profit - but so far he ain't biting (about 50Lbs of it in his office) - the medical suppliers want him to pay them to take them back...

                          Lynn

                          All heavy metals accumulate in the body and are nearly impossible to get rid of. Cadnium was not considered toxic 5 years ago - by industry or EPA - it always was by chemists. It is important to not just toss those crappy rechargable natteries away because of the Cadnium poisoning that is happening in some ground water systems - there is a National toll free number to call for disposal of these useless batteries (Buy NiMH instead). Don't toss Lithiums out either - ground water leaking into them can eventually make them explode!

                          Because I desolder a lot of boards - I get a lead test biannually. I no longer use Lead based solder, but that crap is still out there and I keep sucking it off boards with my Hakko. If I was stilll shooting lots I would get tested more often. If you cast bullets it is important to get and wear a particulate mask while casting that coves nose and mouth. My lead levels increased without one - so be careful.

                          Comment


                          • #14
                            Thanks for the caution Thrud.
                            This is an area that should receive a lot more publicity for the public at large. Of course lead hazards have gotten a lot of publicity in the last 15 or 20 years. But I'm confident 90% of the public never give a thought to other metal hazards. While most will not likely receive a lot of exposure, one never knows.
                            Lynn (Huntsville, AL)

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