Alloy mixture

[rlb]

So I have around 300 lbs of pretty good lead. I would like to get it up to around 13-15 bhn. Super Hard from Rotometals seems to be the way to go from what I have read.

Could you guys give me some ratios, not percentages, to give a try to get close to the bhn I am looking for?

Thanks in advance.

[randyrat]

I'll give it a go and see if this will work.Lets do a 100 lb batch

Lyman #2 you need= 90 lbs of soft lead + 5 lbs of Sb(Antimony) + 5 lbs of Sn(Tin) to equal BHN of 13-15
The problem is 5 lbs of Linotype is not equal to 5 lbs of Antimony so your gonna have to fudge it a bit.
I would lower your lead and up your Linotype a bit

One question; Are you starting out with dead soft lead or is there some hardness to it?

[randyrat]

One more thing; Can you get by with Wheel weight hardness? If yes, use 3 lbs of Lino and about 1% or less of Tin to 90 lbs of lead.
Remember this- your new alloy won't have any Arsenic in it so it may not water drop harden if you choose to do that..

I prefer to water drop Wheel weight lead: Less brittle, much tougher and less cost. I think you can water drop WWs to about 18 BHN

[303Guy]

You could add a little copper for toughness. The percentages are around 0.5% up to maybe 2% but I'm not sure about cast-ability at higher levels. They say to cut back the antimony and substitute the amount with copper. Check the threads on it.

[rlb]

Well thanks Randy for the input. I thought maybe there might be more responses than what I got.

[Okie73]

Download the lead alloy calculator from the stickies section. A very valuable tool.

[rlb]

All I have is an iPad for Internet and it won't let me download it on this thing or I would have it already.

[Defcon-One]

So I have around 300 lbs of pretty good lead.....

You probably would get more responses if you told us what you are starting with? "Pretty good lead" doesn't really tell me much. What type of lead or what does it contain or at least what is the current hardness of you 300 lbs. of lead?

All things that you would need to know to make a plan to alloy up or down to 13 to 15 BHN. If we know what you have, we can help get you there!

[randyrat]

Take a piece of your "pretty good lead" and drop it on some concrete and tell me, does it go;
Thud, dong, ding Ring, Ting. The higher the pitch the harder the lead.....Same as testing an Anvil for hardness, of course, different pitch.
If your "good lead' goes thud you know it is soft lead, if it has some "tone" to it then we know it is not pure soft...

Now for adding copper, you can buy some pewter and add to your lead and it will harden it up real nice also. (pewter has a number of hard alloys in it including a high percent of Tin(Sn) in it to help with casting.
Do a search for Pewter on this site and you will have a weeks worth of reading....

Another option; buy some Wheel weight alloy and mix it 50/50% and then you can "Water Drop" to harden--More reading....

What ever you decide on mixture make sure you document and make smaller batches, your alloy needs may change down the road..

[rlb]

Ok, about 290 lbs is dead soft lead and the other approximately 10 lbs is wadcutter bullets with no lube grooves but rather knurling for the lube. My best guess is they are pretty close to pure. I have 30 lbs of x ray room lead from sheets, another block approximately 60 lbs that is soft enough you can almost peal it just by looking at it, and another that is just under 200 lbs which is just as soft as the other.

[Brenden]

http://www.lasc.us/SuperHard.htm this page lists several recipes for adding superhard rotometals alloy to different lead mixtures, hope it helps.

[Brenden]

I guess its worth noting that on rotometals website it says superhard alloy doesn't have any tin in it and the recipes in the above link show tin. I guess you will have to add that in as well.

[GlocksareGood]

From my calculator 100lbs of Soft + 16lbs SuperHard + 2.37lbs Tin = 118.4lbs of a 12.9BHN. Would give you ~ 94%PB, 2% SN and 4% Sb

[el34]

I melt my wheel weights and make ingots, then measure the hardness of a couple with a Lee tester (~$55 if you can find one available).

Rotometals Superhard has a hardness of 36BHN.

The equation below will let you calculate how much Superhard you need to get your softer stuff up to whatever BHN hardness you want, where x represents pounds of Superhard you'll need-

(x*36) + (pounds of softer lead*its BHN) = (x+pounds of soft)*desired BHN

Example- you determine you have 300 pounds of wheel weight lead ingots that measure 7.2 BHN (realistic for a mix of COWW and SOWW).

You want to know how much Superhard to mix with it to get a result of 14BHN.

(36x) + (7.2*300) = (x+300)*14
36x + 2160 = 14x + 4200
22x = 2040
x = 92.7
So you need 92.7 pounds of Superhard ($430!!) to bring your 300 pounds of BHN 7.2 lead up to BHN 14.

You can use this equation with any high-antimony lead if you know its hardness. If you have linotype and know its hardness is 22 (typical), use 22 instead of the Superhard value of 36.

That means melting twice, once to get ingots out of whatever lead you have and measuring the batch hardness, then a second melt to mix in high-antimony (Superhard) and tin. I've made 100's of lbs of 'casting alloy' this way with dead-on BHN results.

I put this in a simple to use Excel thing that also computes how much tin you need to get whatever % you want, typically 2%. There's a sister version that starts off with your telling it how much Superhard you have and it'll tell you how much wheel weight ingots it'll treat. If you plop in your costs for the ingredients it'll tell you resulting cost per pound, and number of boolits/cost per boolit if you tell it boolit weight in grains. If you're interested, PM me with your email and I'll send it as an attachment.

Bill

[rlb]

Cool guys. This was just what I was looking for. Thanks for everyone's input.

[Defcon-One]

Sometimes it is best to trade dead soft Pure Lead for COWW or similar Lead with Antimonial content around 3%. You can usually trade 1:1 or better and you avoid the cost of Superhard.

With all that you have, that is what I would do. A couple large trades, maybe with a muzzle loader enthusiast would solve your problem!

[AABEN]

Yes I use a log spiter to cut my large blocks of lead.