Author Topic: Crystilline brittleness in cast ingots  (Read 636 times)

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Online Land_Owner

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Crystilline brittleness in cast ingots
« on: December 22, 2010, 02:31:13 AM »
As I learn more about this hobby (which as you already know is extremely habit forming and I LIKE IT), I have cast 50-plus ingots (~3.0# each) of unknown hardness (air cooled) and unknown chemical composition by melting a known weight of lead (50#'s) and adding an approximate weight of WW's (~25#).  Two batches.

Some of the ingots are "crystalline" in the middle where I poured the lead into the ingot mould and as such is brittle there with some ingots breaking in half before they were sufficiently cooled leaving a "cast" look to the broken face and not the anticipated "putty-like" deformation of lead.

Some ingots were made with mostly the stick on type WW's while the remainder were mostly clip on type.  I can not tell which ingots are which...nor do I think it necessary.  I am not shooting for National Match accuracy.  Eventually, just handgun plinking (45 LC and 357 Mag) and 100-200 yard rifle hunting (30-30; 45 LC; and 357 Mag).

Interestingly, if warranted, I read to recast these weights together and repour ingots such that their individual constituents will be more nearly the same.  I wonder whether this really matters?

Offline D Crockett

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Re: Crystilline brittleness in cast ingots
« Reply #1 on: December 22, 2010, 03:52:24 AM »
sound like you are dumping the ingots to fast and they are breaking in1/2 if so just give the ingots a few more minutes in the ingot mould . and I think I would remelt them to get the alloy more uniform I would get some solder to add to you casting pot when casting bullets it will help in  filling out the mould you will get nice sharp edges and will make you bullets a little harder if you want to keep your clip on ww seperate from you stick on ww I will make you some small ingot moulds that way you can just look at the ingots and tell what they are . to tell the difference in hard or soft ingots hit them with a hammer and the ones that ring are hard lead and the ones that don;t are soft lead  they will make a different noise when hit with a hammer I hope this helps D Crockett ps have a marry Christmas

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Re: Crystilline brittleness in cast ingots
« Reply #2 on: December 22, 2010, 07:28:37 AM »
DC...good stuff there.  I intend to remould these ingots, combining them for a more uniform cast.  That idea about adding tin is good.  I believe I would like a final BHN in the 17-19 range.  I am going to use a towel and air dry the boolets, purchase a hardness tester, and heat treat if required.

Do you make a "VVVVV" shaped ingot mould (instead of the single "V" shaped stand alone ones)?  It would go well for me to have a four or five ingot moulds in a single setting, each flush with the adjacent mould and seam welded down the long axis of each interior "V", such that a continuous pour could occur.   I would cut a small "u" channel between the interior "V's" of the mould with a grinder so liquid lead could spill over to adjacent cavities.  Something to consider.  I don't weld...yet, but I am a cutting and grinding "madman".

Offline D Crockett

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Re: Crystilline brittleness in cast ingots
« Reply #3 on: December 22, 2010, 07:59:13 AM »
I can make up to 4 cavity moulds in any length you want that is easy with my new chop saw I made up 2- 3 cavities and 2-4 cavities moulds just to see how they would work it was a learning thing I ended up making two jigs to wield them up with so I could keep the cavities in line but after that I can make all a person could use in fact I am thinking of making a bunch up for my own use instead of all the single cavity moulds I have D Crockett

Offline Northern Flatlander

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Re: Crystilline brittleness in cast ingots
« Reply #4 on: December 26, 2010, 07:57:52 PM »
Zinc contamination!?
Check if you can cast a few good bullets with those non-conforming ingots.
I hope you can.
Dwayner