Results 1 to 7 of 7

Thread: Question for bullet casters

  1. #1
    Join Date
    Aug 2008
    Location
    Ashford
    Posts
    1,222

    Question Question for bullet casters

    Can anyone tell me how you know if your lead melt is contaminated?

    I just picked up some lee casting gear and 12Kg of what i was told were lead ingots from flashing scrap.

    First melt was fine and poured a couple of hundred pretty good rounds.
    Today on the second attempt the bullets started coming out with a bright blue tint in places and hints of a blue crystalline substance in them. Also the melt developed a huge quantity of bright golden dross.

    I was using a wooden stick to stir it so the charcoal from that should have served as flux.

    I'm casting for muzzle load so i want the lead as pure as possible.

    I'm hoping someone can explain what's going on?


  2. #2
    Join Date
    Nov 2007
    Location
    nottingham
    Posts
    512
    Sounds normal, maybe casting temperature is a bit hot. The colour is just through refraction through the oxide layer. Without using assayed pure lead, with a certificate of purity or an electron microscope you will not be able to determine what you have. Watch for the metal going through a "mushy" stage between turning from solid to liquid and vice versa. A pure alloy will undergo a clear cut phase transition between solid and liquid phases, though some specific alloys, called eutectic, will do this too but these are very specific alloys. If you are loading for a revolver then anything harder than pure lead, roughly 8 BHN, will be a very hard to load. If for Minie bullets then simply try them, also pure lead will cast smaller; a .577 Minie cast for WW alloy comes out at .582" as opposed to .576" from the same mould.

    The discolouring will have no impact on how the bullets shoot. The crystalline appearance is from the fact that, like all solid metals, lead is crystalline.

  3. #3
    Join Date
    Aug 2008
    Location
    Ashford
    Posts
    1,222
    Thanks Andrew.

    I'll have another go next week and see if i can get a better pour. Sounds encouraging though.
    Currently I'm only trying .457 balls for a Ruger Old Army I'lll hand some over to the folks at the club and see what they make of them.

  4. #4
    Join Date
    Feb 2008
    Location
    Huntingdon
    Posts
    9,253
    I'd be interested to know how much the ball you are casting actually weigh. Pure lead - as pure as we can get here without buying lab samples - SHOULD cast a .457" ball about 145/6gr.

    Some of the ball I've cast using 'lead' flashing offcuts have weighed around 125gr or so.

    Plainly, what we are looking at here, as far as flashing lead is concerned, is not lead as we know it, Jim.

    The best stuff I've ever had came out of our old house in Chester - the pre-WW1 plumbing. That stuff was pure gold to a caster, if you'll forgive me mixing metaphors.

    You might get better results fluxing with a small piece of beeswax, or maybe borax powder.

    tac

  5. #5
    Join Date
    Jun 2010
    Location
    Manchester
    Posts
    8,331
    If it is cooling with a blue tint it would indicate that it is lead a pure as we can get it. If it hardens with a frosty appearance then I would suspect there is a small amount of tin in there.

    You do not need to flux pure lead. That is only done when using a tin/alloy mix and the tin separates out.
    Anything that floats to the top of the melt with unalloyed lead is dross and needs to be skimmed off.

  6. #6
    Join Date
    Jun 2005
    Location
    leeds, west yorkshire
    Posts
    12,946
    i flux with sawdust.
    everytime i cut wood i save the dust and keep it for casting.
    i sometimes get a blue tinge so dont worry about it.....my lead came from old houses

  7. #7
    Join Date
    Dec 2008
    Location
    Warminster, Wilts
    Posts
    726
    If the lead flashing is good quality and to the relevant BS then it should be 99.8% pure lead or better.

    As others have pointed out small amounts (1-3%) of other metals, typically tin or antimony, in the mix will change things quite a bit - and some of the changes can occur over time or even vary over time. The older wheel weights also had Arsenic in them which allowed heat treatment of lead alloys so you can quickly get into issues if you do not know the real source of your casting materials.

    Keeping the mix at a constant temperature helps using something like a PID (but not sure how much with pure lead, I only use 'alloys').

    Regardless of the mix I would flux, stirring with a dry hardwood stick seems to work for me, do whatever you're happy with, as there's always crap in there of one form or another.

    Do you have access to the hardness gauge of any kind, found these indispensable in the long run?

    Brgds Terry

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •