Iso core lead questions / alloy identification

[loadmak]

I picked up a few iso cores a while back and smelted some today.

The iso core looked like this:
72067

It produced ingots that look like this:
72068

Compare that to a typical COWW ingot.
72070

I melted another iso core; this one is a little different looking. It's smoother and has sharper edges. It had a couple embedded steel clips. (I almost forgot to take a pic before it melted)
72071

It created a nice looking ingot similar to the COWW ingots. The surface looks a little more crystalline than most. The iso ingot #2 is on the right.
72072

I smelt my lead at 650-700 degrees. Has anyone ever seen the bluish/purplish color and the strange flow lines in an alloy? Any idea what that alloy is?

[Defcon-One]

Your first batch is probably near pure lead and you may have run it a bit too hot. The blue is just lead oxides caused by the extra heat which accelerates oxidation. The wrinkles are more common on pure lead without Tin as it does not flow as well. Probably cast it in a cold mold, which would cause more wrinkles due to the quick set up.

The second batch is gonna be the typical large Isotope Core and will be about 1% Tin, 3% Antimony, 96% Lead. It will act just like COWW with 1% Tin. This one is better for most bullet casting.

I do not know why your two cores were different, but clearly they were.

[383]

I have smelted several of the isotope cores like the one in the first pic. I smelt at about 700 deg if my Tel Tru is correct. I haven't noticed the rainbow pattern shown. Iso cores are reputedly 96/3/1 in composition.

[Ole]

Does the core in the first picture weigh 31.5 lbs?

It looks a little bit different than the cores I've bought. It almost looks like the angle on the bottom of the core is steeper than the ones I have seen.

Might be just from the picture. If your cores weigh 31.5 lbs then disregard.

[Ole]

loadmak here is what the cores I have all look like:

http://i258.photobucket.com/albums/hh280/Ole1830/IMG_5853_zps3f1b8a96.jpg (http://s258.photobucket.com/user/Ole1830/media/IMG_5853_zps3f1b8a96.jpg.html)

Similar, but slightly different on the bottom.

[Defcon-One]

That is exactly what his second core would have looked like before the pot melted it! You can still see some of the details in the pic.

All of mine look like yours Ole and they do weigh 31.5 lbs. plus or minus a few ounces.

The one in the first pic is the different one. I have not seen that one before? Clearly softer lead.

[B.C.Jay]

I've got some like the first pic and they seem to be near pure. They are definatly too soft to be 3/1/96.

[loadmak]

Ole, my second one was exactly like yours, including the label which you see burnt in the picture. Both types were in the 31 lb. range. I have four of the first type and one of the second type. My first iso core acquisition. I'll pick the second type from now on if I have a choice :) .

Should I re-smelt this batch with some added tin, or use them as-is and blend it in the casting pot?

[el34]

Loadmak- where'd you get them? What was their price?

[383]

Ole, my second one was exactly like yours, including the label which you see burnt in the picture. Both types were in the 31 lb. range. I have four of the first type and one of the second type. My first iso core acquisition. I'll pick the second type from now on if I have a choice :) .

Should I re-smelt this batch with some added tin, or use them as-is and blend it in the casting pot?

Actually these are what I smelt, label and all. My bad.

[loadmak]

Loadmak- where'd you get them? What was their price?

I got them from a nuclear pharmacy after reading about them on a forum. I did an internet search, but there are none of those in my area. I was out of town once on business in a city that I remember had one of these places. I called and talked to the manager, asking if he had any lead he could part with. Turns out he did. He normally waits until he collects a bunch and then calls a recycler to come pick it up. He said he would sell it to me for the same price he sells it to the other guy - fifty cents a pound. I drove right over and he asked me if .40/lb was ok. :) I picked up 5 cores - 4 of the first type (pure lead?) and 1 of the second type.

[383]

Good score. FWIW pay .60/lb for mine.

[Andrew Mason]

i have some iso cores, and i use them for casting my .38/357 boolits,

talk about a great alloy to cast with.

i get my iso cores from a member on here, i trade him lb-lb pure lead for iso cores.