0.5-0.7 % Zn in alloy, is that a problem?

[hunter74]

I bought some roof lead and som mystery lead from my local dealer today.

Earlier I've used a lot of roofing lead without problems. Since he had a 200 # chunk of mystery lead, I got him to "shoot it" with his XRF gun, at it showed about 0.7 % of Zink.

I also got him to test the roofing lead plates and it showed about 0.5 % Zink. This surprised me because I have been under the impression that this was pure and some of the best lead you could get for boolit casting at the scrap yard.

So.... My question is simply, is these small amounts of Zn a reason for consern or should I just melt flux and "alloy up" to feed my hungry Bullet Master with it? I've used a lot of this kind of lead in the past but I've alwas thought the gray stuff on the top was Sb and Sn. The boolits have always been good, but with this new information on hand I would like to have some expert opinions from you guys!

Thanks!

Sent fra min SM-G930F via Tapatalk

[rancher1913]

did he shoot a cleaned off spot with the gun? those guns only read what is on the surface so if the surface has been against zinc and some rubbed off it will show zinc on the read out. find it really hard to believe the flashing has zinc in it.

[hunter74]

Rancher 1913, the flashing he just shot, and it was not clean, so you may be right.

The chunk with mystery alloy he grinded off a small flat surface and tested it there so this reading would be more accurate. According to the scrap yard man this was remelted from balance weights used in boats, I think.

I hate to throw away 200 lbs of 0.7 Zn lead. Would you used it and alloy it with printers lead or would you "water it out" with more pure to get the Zn percentage down before alloying?

Sent fra min SM-G930F via Tapatalk

[BK7saum]

I think runfiverun has commented that up to a certain percentage, Zn adds hardness. You might have to cast a bit hotter or add a bit more tin to get it flow like it needs to. I don't think 0.7% is a problem, but I really don't know. I think the 1.5-2% was the cutoff where it started to affect castability.

Brad

[fecmech]

I screwed up a smelt some years back with zinc. I have no idea what percentage but I'm sure way more than .7. I added tin to the mix and was able to make good quality pistol bullets.

[JonB_in_Glencoe]

I did a test with precisely 1% zinc in a boolit alloy, as I wondered about hardness. I was able to cast with it, but I did have an issue with dross.
see post #6 and beyond.
http://www.artfulbullet.com/index.ph...let-alloy.589/

[Oklahoma Rebel]

i think below 1% should be fine

[popper]

If you can cast good boolits with it, use it. Depending on what else is in it, it may cast small. Sn will make fillout better and you may need a little more heat. I shot some 0.7% Zn/pure in 40SW, got tumbling at the target. Had to beagle the mold to get proper size and I think I swaged the soft alloy down when I used the taper crimp die.

[runfiverun]

a bit more heat will help.

there used to be this crazy guy that run around Africa with powder in his right side pockets and round balls in another one.
he would re-load by grabbing a handful of black powder and dropping it in the barrel then ram home a 3% zinc-pure lead ball.
the extra BHN increased penetration, which I could see being useful when something is trying to come eat you through a cloud of smoke.

[hunter74]

I usually use 1 part monotype to 4 parts of pure. I'll try that with this lead also and see how it turns out. For my smallest boolits like 32 WCs and 38-105 SWCs I usually add a little Sn to get better fillout in addition to run the moulds a bit hotter than I normally do.

Maybe I can skim off some of the Zn when making ingots of the big chunk if I don't get the melt over 700 F?

I've heard horror storys about Zn in the pots and difficult clean out processes so I appreciate the inout before using this lead in my bullet master.

Sent fra min SM-G930F via Tapatalk

[BNE]

It's interesting that the gun read the same amount in both samples.
It maybe reads 0.7% of anything you test is Zinc. The XrF guns are not perfect.

Try Roy putting some muriatic acid on the lead. If it bubbles, then you do have some Zinc. If not, then you don't.

[6622729]

You already own the stuff, I'd cast it. If it casts ok, weigh the boolits and work up a load for that alloy at that hardness and enjoy your 200lbs. I wouldnt get worried about the composition if it casts and shoots well.

Rancher 1913, the flashing he just shot, and it was not clean, so you may be right.

The chunk with mystery alloy he grinded off a small flat surface and tested it there so this reading would be more accurate. According to the scrap yard man this was remelted from balance weights used in boats, I think.

I hate to throw away 200 lbs of 0.7 Zn lead. Would you used it and alloy it with printers lead or would you "water it out" with more pure to get the Zn percentage down before alloying?

Sent fra min SM-G930F via Tapatalk

[JonB_in_Glencoe]

I usually use 1 part monotype to 4 parts of pure. I'll try that with this lead also and see how it turns out. For my smallest boolits like 32 WCs and 38-105 SWCs I usually add a little Sn to get better fillout in addition to run the moulds a bit hotter than I normally do.

Maybe I can skim off some of the Zn when making ingots of the big chunk if I don't get the melt over 700 F?

I've heard horror storys about Zn in the pots and difficult clean out processes so I appreciate the inout before using this lead in my bullet master.

Sent fra min SM-G930F via Tapatalk

As I understand it, Zinc and Tin have a special relationship...I would bet that having plenty of Tin in a lead alloy with 0.7% Zinc will help it cast better. So blending an alloy with Monotype and/or adding Tin, as you mention, should help you avoid casting problems. But if you read about my test, and the oatmeal dross that developed when the pot's alloy level got low...if that would be a problem with your bulletmaster, than maybe that alloy won't be the ideal thing to use. On the other hand, when I dealt with the dross issue, it only took about 4 pot fulls of alloy to clear out the problem.