Please check my math (alloy)

[daschnoz]

1# of WW + 1oz. Sn = about Lyman #2

By my math, I end up with 90% Pb, 4.7% An, 5.3% Sn.

Does this look correct?

[Wireman134]

Total wt of alloy is 17oz. Based on a WW's having 95.5%Pb/.5%Sn/4%Sb. I brake the components down to oz.'s. Multiply the percentages of elements X total weight, in this case 16oz. 95.5%Pbx16oz=15.28oz.PB, .5%Snx16oz.=.08oz.Sn, 4%Sbx16oz.=.64oz.Sb. Then add the other amount of Sn (1oz.) to the existing amount in the WW's for total Sn of 1.08oz. Divide the total elements into the total, in this case 17oz. You get 89.88%Pb/3.76%Sb/5.88%Sn.

[sagacious]

No, does not look correct. Would clarify considerably if you listed your math, and not just the answer. The chemical symbol for antimony is Sb.

The short(er) answer is that ww's likely do not have any where near that much Sb. WW's may have had that much Sb back in the 70's when Lyman came up with the fuzzy math for ww's + 50/50 = #2.


You get 89.88%Pb/3.76%Sb/5.88%Sn.
Those sums total to 99.52%.

4% antimony is probably optimistic these days. Half that percentage of Sb is likely closer to the actual amount. Just depends on of one wishes to guesstimate conservatively or lavishly.

If your ww alloy is 1%Sn, and 2%Sb, and 97%Pb (disregarding the As),
Adding 1oz of Sn to 16ozs "ww alloy" equals
6.82%Sn
1.88%Sb
91.3%Pb

Now someone needs to check my math lol! :)

[cbrick]

Well, 1 pound of WW = 7000 gr
1 ounce of tin = 437.5 gr or 6.2% of the full 1 pound, the lead, the Sb and about one half of one percent tin already in the WW (35 gr).

If An is antimony you've got some great wheel weights there, best to figure Sb at 2% (welcome to the 21st century).

6387.5 gr of lead (91%), 140 gr of Sb (2%) and 472.5 gr of Sn (6.8%). Sb and Sn rounded off to the nearest tenth.

If it were me I would pull back on the Sn, no need or benefit to nearly 7% tin, wasteful and expensive.

Rick

[daschnoz]

I'm trying to get an alloy around 15 BHN or better (for the FAL).

Using the numbers in the Lyman 48 on page 81 as a ref., they show that WWs have a BHN of 9. Here http://www.lasc.us/CastBulletNotes.htm , they show that WWs have a BHN of 12.

Someone needs to check their numbers.

I have about 60# of WW ingots, but no way to measure their BHN. It sounds to me like I need a BHN tester kit. Is the LEE tester any good? Midway has it for $51. If someone has one for sale, drop me a PM.

[cbrick]

If clip-on weights and stick-on weights are blended together the BHN would be about 9, perhaps this is what Lyman did. All of the many hundreds of pounds of CWW I've checked since the early 90's run 11-12 BHN.

Rick

[daschnoz]

I have a mix as well, but a large portion of the bulk is clip-ons. I actually pulled the stick-ons when I realized that they were pure, and used them for the front stuffer. That said, there still are a few # of stick-ons in the alloy. I need a tester; plain and simple.

[Wireman134]

A tenth of a % means nothing in real world. If you try for Bhn 15, I do it with Approx. 96.5%Pb/1.7%Sn/1.8%Sb water dropped tested this method.

http://castboolits.gunloads.com/showpost.php?p=795603&postcount=35

[cbrick]

A tenth of a % means nothing in real world.

Exactly.

I only put in my post that it was rounded off because someone would post that it didn't add up. Ballistically even 1% is statistically irrelevant much less tenths.

Rick

[Wireman134]

Well, 1 pound of WW = 7000 gr
1 ounce of tin = 437.5 gr or 6.2% of the full 1 pound, the lead, the Sb and about one half of one percent tin already in the WW (35 gr).

If An is antimony you've got some great wheel weights there, best to figure Sb at 2% (welcome to the 21st century).

6387.5 gr of lead (91%), 140 gr of Sb (2%) and 472.5 gr of Sn (6.8%). Sb and Sn rounded off to the nearest tenth.

If it were me I would pull back on the Sn, no need or benefit to nearly 7% tin, wasteful and expensive.

Rick

1 pound of WW's + 1oz.Sn=17oz. or 7437.5gr. 7437.5gr. total/437.5gr. Sn (disregarding the minute amount of Sn in the WW's)= 5.88%
Does it really matter what the actual mix is as long as you can duplicate the BHN you want. Use the known to be percentages as a guide and adjust accordingly to suite. :-)

[HeavyMetal]

Clip on WW content varies by manufacturer and the geographic location they are at.

Seprerating stick on's from clip on's has always been a good idea but if you want a consistant alloy with a consistant BHN then a hardness tester is the only way to accomplish this.

My thought on this is as long as the BHN stays close and the weight stays close to each individual batch cast then you will be in the "Ball Park".

The only way to better this is to actually order a custom alloy in 100 pound lots. This way you get what you want and get documentation to prove it.

[sagacious]

A tenth of a % means nothing in real world. If you try for Bhn 15, I do it with Approx. 96.5%Pb/1.7%Sn/1.8%Sb
Wireman,
Please do not take this as criticism, but if 1/10% means nothing, why do your own recommended percentages above show 1/10% resolution? 96.5% is ninety-six and five tenth's of a percent. In the real world, five tenth's of a percent is nearly two ounces of tin in a 20lb pot.


1 pound of WW's + 1oz.Sn=17oz. or 7437.5gr. 7437.5gr. total/437.5gr.
If 1/10% doesn't matter, then 1/7000th of a pound seems even less relevant. Giving figures to half a grain is showing resolution to one-fourteen-thousandth of a pound.

Again, not taking anyone to task, just checking the math. Sometimes the math and reasoning is as important as the answer.

Regards to all, and good shooting. :drinks:

[StarMetal]

Do what a lot of us do and that is mix 50/50 WW/lead. You will get that past that hardness if you water quench and very close to it just air cooled. I've been shooting it for years in a variety of rifles and even pushing HV in many of them.

[sagacious]

I only put in my post that it was rounded off because someone would post that it didn't add up. Ballistically even 1% is statistically irrelevant much less tenths.
Rick,
The OP gave his figures in 1/10% resolution. If one is going to check the math, then corresponding resolution is certainly relevant. Each response here lists tenth-percent resolution.

I just check the math. It's not meant as anything personal, nor any sort of reflection on anyone's character. I hold you guys in the highest regard.

Cheers, and good shooting. :drinks:

[leadman]

I would use only clip on wheel-weights, add 1% tin if fill out was a problem until fill out is good.
Water dropping will give you a boolit that will age harden to what will work just fine for most applications.
What are you going to be casting for and the expected velocity?

If you need a harder alloy than the water quenched WW you could heat treat or add some of Rotometals 30% antimony alloy.

I have found the exact percentages of components in the alloy are not as critical as some think, especially if you are not trying for full jacketed velocities in rifles.

[lwknight]

I mix stuff in it till the ingots ring and I cant dent it with a fingernail. We good to go.

[Wireman134]

Wireman,
Please do not take this as criticism, but if 1/10% means nothing, why do your own recommended percentages above show 1/10% resolution? 96.5% is ninety-six and five tenth's of a percent. In the real world, five tenth's of a percent is nearly two ounces of tin in a 20lb pot.


If 1/10% doesn't matter, then 1/7000th of a pound seems even less relevant. Giving figures to half a grain is showing resolution to one-fourteen-thousandth of a pound.

Again, not taking anyone to task, just checking the math. Sometimes the math and reasoning is as important as the answer.

Regards to all, and good shooting. :drinks:

Clarifying the tenth of % variation is of little consequence.:takinWiz:

[sagacious]

Yes, it may be of little consequence. I reckon the OP can make up his mind on that.

I was just indicating that your math and alloy estimation were both wrong, that's all. More than a little humorous in a "please check my math (and alloy)" thread. :-o