This topic contains 3 replies, has 3 voices, and was last updated by  Artful 9 months ago.

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  • #49504
     Glenn 
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    It used to be that you buy a bucket of wheel weights, throw them in the smelter, skim off the clips and you were left with a pot full of wonderful stuff.

    Now I throw them in the smelter and there is some fluffy stuff that floats on top of the melt with the clips.  I think the wheel weight manufacturers are adding some kind of cheap metal to use as a filler to make them cheaper.

    Here’s my pot at 750F with wheel weights in it after fluxing and all of the fluff scraped to one side.

    Spoon it out and this is what’s left.

    Here’s the pile of Fluff that I’ve been collecting.

    I took one spoon sized piece, set it on an ingot mold and heated with a propane torch until it glowed red.

    So, what do you think?  What kind of Mystery Metal is this Fluff?  It is not attracted to a magnet and is lighter than a similar sized piece of lead.

  • #49512
     Artful 
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    Looks like Zinc to me, Zinc is nonferrous.

    Zincs melting point is 419°C (786°F). Zincs density is 7.14 g/cm3

    Zinc is naturally dull grey and is very hard to polish

    Put a drop of copper sulfate solution on it. If it’s zinc, it will turn dark while aluminum will show no color change.

  • #49514
     Goodsteel 
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    Yep. You got zinced. Throw it in your pond and don’t mess with it. Any random batch of wheel weights made in the past ten years will be 30% zinc and steel or more. They all have to be carefully seperated before smelting, or you have to keep your smelting pot temperature very carefully set at 700 degrees so the zink doesn’t melt into the good alloy and floats with the steel.

    There’s no way to get the zink out once it’s been melted into the lead. I’ve lost two 50+ pound batches of lead this way over the past decade, and it always makes for a very unforgettable occurrence.

  • #49516
     Artful 
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    Flux it with fine saw dust (and a lot of it) – it can remove zinc.

    also

    http://castboolits.gunloads.com/showthread.php?62957-A-possible-way-to-remove-zinc-from-molten-lead

    http://chestofbooks.com/home-improvement/construction/plumbing/Practical-Plumbing/How-To-Make-Solder.html

    Burning the solder must be carefully avoided. A pot of solder after it has been red-hot has always a quantity of dross or dirt collected on the top. This is principally oxide of tin and oxide of lead, the tin and lead having united with the oxygen in the atmosphere to form oxides of these metals. Lead being roughly 50 per cent heavier than tin, the tendency is for the tin in the molten mixture to form the upper layer of the solder – the part most exposed to the action of the atmosphere. When the solder becomes red-hot, there is therefore more tin burned than lead. Hence the solder becomes too coarse, and more tin must be added. Zinc is the greatest trouble to the solder pot. Great care has to be taken to exclude it, or to get it out. It may get into the solder from a piece of zinc, having been put into the pot by mistake for lead, but more commonly brass, which is an alloy of copper and zinc, is the source of the zinc that poisons the pot, into which brass filings find their way whilst brass is being prepared for tinning. If the filing is done at the same bench as the wiping, splashes of metal may fall on the filings, which will adhere, and thus get into the pot. Solder that is poisoned by arsenic or antimony is beyond the plumber’s skill to clean, but zinc can be extracted by stirring in powdered sulphur when the solder is in a semi-molten condition, and then melting the whole, when the combined sulphur and zinc will rise to the surface, and can be taken off in the form of a cake, the solder being left in good condition for use.
     

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