Another mixing question.

[cwlongshot]

Sorry guys I just cannot wrap my head around this. When I think I have it I read something or re analyze in my head and Im questioning again!!!

Ok here goes. I have a quantity of RIMFIRE BULLET ALLOY. Calling it pure lead untill I learn different.

I was gifted some Super Hard


Id like to achieve COWW equilivent. Ill be doing this in a 20# Pot.

Whats my ratio?

CW

[454PB]

I would use 1 Super Hard to 9 "pure lead". Should end up around 3% antimony, 97% pure lead. You'll then need some tin for fluidity, WW alloy has about .5% tin. Those .22 rimfire boolits may have some tin already.

[Winger Ed.]

WW alloy is great, but you might do well to conserve the expensive 'goodies' in the hard stuff.

For slow boolits- I wouldn't add in any more hard stuff than it takes to get a good fill out in the mold.

For faster & faster, you'll probably want the alloy to be some what harder.

[bruce381]

down load alloy calculator you can even put in prices


http://castboolits.gunloads.com/showthread.php?105952-Lead-alloy-calculators

[cwlongshot]

Thats what I dont get!

Im on a iphone here...


CW

[William Yanda]

I googled Super Hard and it took me somewhere I did not want to go.
Super Hard bullet alloy shows 70/30 lead/Antimony ratio. Assuming 3% antimony for COWW, 454PB is correct at one to 9.
You didn't tell us why you want COWW. Many casters find half COWW, half lead to be a good alloy for their purposes.
Based on reading LASC articles I like to balance the Antimony and Tin but to date all my product has been by guess and by gosh.
It would make your Super Hard last twice as long and that is a good thing whatever the subject.

[ABJ]

Ditto what Bruce posted.
Then you can use the custom alloy line at the bottom to plug in what you think the rimfire alloy is. Based on exp. I would say in the range of 1 to 2.5 percent antimony and a trace of tin.
There is nothing wrong with coww alloy with tin added, its a great general purpose alloy. My own is built up to 2/4 tin/antimony.

My pure ingots weigh 2 lbs. The superhard from Rotometals is melted down in a lee pot and I use a stainless kitchen measuring spoon slightly bent and held in small locking pliers. Then I pour out wafers onto a steel table, weigh on a postal scale and convert to pounds(lbs).

My spoon yields .085 lbs of super hard, which takes 3 wafers to a 2 lb pure ingot for 3.19% antimony. I cast pure Tin in a lee 45/230 tumble lube mould. It takes two of these pure tin boolits to one 2 lb ingot. A 230 pure tin boolit weighs .020 lbs.

Sorry for the rambling, but all this to say the Alloy calculator is one of the best things ever GIVEN to us to narrow down and not waste components as well as being able to have consistent alloys from batch to batch. As long as you know or pretty close on the components the calculator will save time and money for you.
Tony

[kevin c]

454PB has the ratio right.

If you want to do it with pencil and paper, you can think of the 30% Sb in SuperHard as 30 percentage points of Sb that need to be divided equally into the total amount of alloy. In your case, you want 3% in each pound, so you "leave" 3% in each pound of SuperHard added, giving you 27% to divide into the rest of the alloy mixed with that one pound of SH. If that alloy is pure, you need a whole 3% each, meaning the pound of SuperHard has enough for 9 more pounds, so your final mix will be 9# pure for every 1# SH, a total of 10#. Another example: to end up with 6% Sb starting from 4% alloy and SuperHard, for each pound of SH, leave 6%, so 30 - 6 = 24 parts of Sb available to divide into the rest. The rest is 4%, needing two more % each pound, so the 24 parts is enough for 12 more pounds; final ratio 12# of 4% for every 1# SH (13# total final alloy).

The above is exact for binary alloys. Ternary alloys with tin are trickier. Easiest for me is to just calculate the tin needed for the main alloy first, then take that total and calculate the Sb needed. The final % tin will be slightly on the low side, but it'll be a small error that likely doesn't change much.

ETA: the calculator is much easier ;^]

[cwlongshot]

So sounds like I should melt the SH into smaller
Ingots to start.


Thats what I have done with my MONO type. So good start!

Thanks guys. Ill try much less than I was thinking!

CW

[fredj338]

I would probably go 4-1. L-Sh. I dont think 9-1 gives you anything close to COWW.

[kevin c]

My impression is that COWW is about 3% Sb, so ten pounds (160 ounces) would have 4.8 oz of antimony. SuperHard is 30% Sb, so one pound (16 oz) has 4.8 oz antimony. Add that 4.8 oz Sb and 11.2 oz of lead to 9 pounds of pure should give the same as ten pounds of COWW.

No tin or arsenic, though.