Alloy not coming out as it should.

[Rickf1985]

Ok, What am I doing wrong here? I am mixing .25lb. pewter and 10lb. of lead and according to the alloy calculator I "should" be getting around 11.5 hardness. I am actually getting something so low it is not on the scale. I am getting a .0850 on the Lee hardness tester. On the printed chart .079 is BHN 8.

The original mix I did the pewter I used was in raw form and marked with the scans of the composition and it was pretty close to what is in the chart. The second mix I did was using some pewter ingots I bought from a member here. Long time member I am sure I can trust to have good stuff. Both mixes came out exactly the same. I could understand if it was just one or two numbers off but what I am seeing is pure lead.
I am shooting this out of a 45 acp so I am going to use it but I want to know where I am screwing up for future use. I have plenty of linotype and wheel weights but both are short on tin. In case you are going to ask I tested many samples on the nose, base and filed sides.

[Rickf1985]

I was just playing with the calculator and found something interesting. Put in .25lbs. of pewter and 10lbs. of pure lead and you get 11.5 hardness. Now, start adding coww. I add 5, 10, 20, 30, 40, 50lbs. of clip on wheel weights and the hardness never changed! Definitely something wrong in there.

[Winger Ed.]

adding coww. I add 5, 10, 20, 30, 40, 50lbs. of clip on wheel weights and the hardness never changed!

Ya might try testing the hardness of just your wheel weights.
If they test out the same as your alloy--- you can add all of them you want and the hardness won't change.

[bangerjim]

There known and unknown glitches in the math used in the spreadsheet. But we live with it.

Bottom line........................Trust your hardness tester for ball park reads after ageing of the boolits you cast. Once you get where you want, write down the weights of each alloy added.

I use the calculator but only as a guideline. I trust my Cabine-style tester 100%, as it has been certified by a NIST tester.

And if you are trying to increase hardness, Sn is NOT the path you want to take. Sb gives you hardness. The ratio of Pb/Sn you mentioned will give you pretty much soft lead. Use your WW's and lino for hardness (Sb) and then add up to 2% Sn for mold fill improvement................if you need it. Sn does not increase the hardness very much, at least not like Sb does.

Do a search for alloy ratios on here. You will find most include some lino and/or mostly COWW's as the 2nd alloy used in the mix, and the Sn is added for fill-out of the mold details. Again, if needed. I have hundreds of pounds of pure Sn (not pewter), so I add 2% to everything up front to avoid any bad castings.

Good luck on your quest for that perfect alloy!

[fredj338]

Well your pewter probably isnt what you thought it was. I actually doubt that tin/lead at what, 40/1, is giving you 11.5bhn. The 8 is probably right.

[Rickf1985]

Ya might try testing the hardness of just your wheel weights.
If they test out the same as your alloy--- you can add all of them you want and the hardness won't change.

I haven't actually added the weights to my alloy, I was talking abut what the alloy calculator shows.

[Rickf1985]

Well your pewter probably isnt what you thought it was. I actually doubt that tin/lead at what, 40/1, is giving you 11.5bhn. The 8 is probably right.

Here is a screenshot of the calculator and what I put together. And as I originally said in the first post the pewter had been scanned and marked and it was very close to what is in the calculator. No, just adding tin will not do much of anything for the hardness but the antimony and copper will. Note the 2.26 tin and 2.44 antimony. Now, what I was trying to point out is IN THE CALCULATOR, I added up to 50 lbs. of wheel weights to that formulae already there and the hardness never increased.
What I am trying to say is everyone is constantly saying to use the alloy calculator. I hear it over and over. NOW I am hearing there are math glitches in the program. This can be very costly to some people (like me!) that do not have massive reserves of lead laying around.
The calculator is a great tool but people need to know that it has issues and they could be mislead. Do the actual math on your own after getting the info from the calculator. I am sure there is someone out there that has the smarts to fix an Excel program, I am NOT that person. A kindergartner probably knows more about Excel than I do. Perfect example of my skills is I have no idea how to make my screenshots bigger.

[GrayTech]

Separate some of your mix, maybe 5lb, and add lino type in small increments and test and see if you can get what you want. Then you have a baseline to work from.

[DAVIDMAGNUM]

...... I actually doubt that tin/lead at what, 40/1, is giving you 11.5bhn. The 8 is probably right.

11.5 BHN is just a little harder that 20-1 alloy . A 40-1 alloy is going to be a 7-8 on the BHN scale.

[JimB..]

@rickf1985 I played with and tweaked the calculator for my own purposes, but the published one is good at most things. The problem you’re seeing is rooted in the fact that the calculator assumes that pure lead is harder than it really is (I think it assumes 8 when it’s really 5). As you move into alloys that are reasonable for traditionally lubed pistol bullets the error becomes insignificant, but for alloys like what you’re describing (40:1) the error is significant. If you correct the hardness of pure lead in the calculator then it may be more accurate for something like your alloy, but less accurate for more typical alloys.

I’m not on my laptop, but I can look the COWW scenario you describe tomorrow. My guess is that you’ve created a hypothetical alloy with the same projected hardness as COWW, so adding more COWW doesn’t change the alloy hardness.

[Mitch]

@rickf1985 I played with and tweaked the calculator for my own purposes, but the published one is good at most things. The problem you’re seeing is rooted in the fact that the calculator assumes that pure lead is harder than it really is (I think it assumes 8 when it’s really 5). As you move into alloys that are reasonable for traditionally lubed pistol bullets the error becomes insignificant, but for alloys like what you’re describing (40:1) the error is significant. If you correct the hardness of pure lead in the calculator then it may be more accurate for something like your alloy, but less accurate for more typical alloys.

I’m not on my laptop, but I can look the COWW scenario you describe tomorrow. My guess is that you’ve created a hypothetical alloy with the same projected hardness as COWW, so adding more COWW doesn’t change the alloy hardness.

This has been talked about here before many times.the use of the 8.6 number for pure lead is from the fast that when adding alloys to pure lead the first small bit of alloy added make the hardness go up realy fast up to about 8 or 9 bhn from there is evens out and it more predictable. from 9 bhn and higher in the usable rage of cast bullets.think of it as a bell curve graph going up fast with very little antimony and tin added it gets to 8.6 bhn and then from there the hardeness chages at a rate of every 1% of tin added the bhn goes up by .29bhn then for every 1% of antimony anded it goes up by .92 bhn. I am not sure how hi of bhn you need to gwt to befro the formula sill not work anymore. this is why it is hard to get an alloy useing antimony that is below 8.6bhn. tin works much better for the alloys below 8.6bhn. i think rotometas knows what they are doing they give the lead hardness right on the page where the bullet casting alloys are. 8.6 fpr pure lead each 1% of tin is .29bhn and each 1% of antimony is .92 bhn. the lead calulaotor here is based on this formula. bottom line is if you use 5 for pure lead and all your alloys are pure you will be about 3.6 bnh to hard

[Mitch]

here is it buy the numbers using the formula that rotomeats gives and the lead alloy calulator is bases on.

.25lb of peweter and 10lb of pure lead gives you 2.26% of tin and 2.44% of antimony 2.26x.29=.655 bhn and 2.44x.92=2.244 8.6+.655+2.244= 11.499bhn

next we add 50lb of coww .5%tin and 3% antimony .5x.29=.145bhn 3x.92=2.76bhn so again 8.6+.145+2.76=11.505bhn

now you have a mix of .8% tin and 2.9% antimony .8x.29=.232bhn 2.9x.92=2.668 8.6+.232+2.668= 11.5bh

you can see by the math the hardness of the coww is 11.5 and that is the same BHN as the .25 tin and 10lb of pure lead the only differance is the bhardness co from a little more antimony in the final mix so if you want more hardness then the soww can give you you need something with a bigger % of antimony. hope this help you out Rick

[PBaholic]

Ok, What am I doing wrong here? I am mixing .25lb. pewter and 10lb. of lead and according to the alloy calculator I "should" be getting around 11.5 hardness. I am actually getting something so low it is not on the scale. I am getting a .0850 on the Lee hardness tester. On the printed chart .079 is BHN 8.

The original mix I did the pewter I used was in raw form and marked with the scans of the composition and it was pretty close to what is in the chart. The second mix I did was using some pewter ingots I bought from a member here. Long time member I am sure I can trust to have good stuff. Both mixes came out exactly the same. I could understand if it was just one or two numbers off but what I am seeing is pure lead.
I am shooting this out of a 45 acp so I am going to use it but I want to know where I am screwing up for future use. I have plenty of linotype and wheel weights but both are short on tin. In case you are going to ask I tested many samples on the nose, base and filed sides.

The calculator is only accurate in the linear part of the curve (final BHN of 11 to 14). Also, you can't measure fresh lead.

Pewter is mostly Tin (Sn), but can contain trace amount of Antimony (Sb). What you made was 97.5% Pb, 2.5% Sn and a trace of Sb. If you look at the chart here for this mix, it should be about BHN 6.5 when it has aged about a week. You shouldn't even test lead for at least 24 hours, as it hasn't fully crystalized yet.

You don't mention what you are trying to get, but a good mixture is 97% Pb, 1.5% Sn, 1.5% Sb (97:1.5:1.5). You mentioned you have Lead, Pewter and Lintotype. The recipe would be:

10 Lbs Pb
1.5 Lbs Linotype
2 Oz of Pewter

This mixture will give you a BHN:
1 Day = 9.0
2 Days = 10.5
7 Days = 10.9
30 Days = 12.5
60 Days = 13.8

I've made this alloy, but it was harder than I needed. I Powder Coat, so I only need a BHN of 10 for my 45 ACP's, and am currently testing 99:0.5:0.5.

[JimB..]

Thanks @Mitch and @PBaholic, well said.

[Rickf1985]

Here is another interesting quirk about the alloy calculator. If you look at line #18 you will see 40/60 solder with a hardness if 15. Ok, now go down to the lines at the bottom that are marked "custom alloy" and type 40 in the tin column and hit enter. It will automatically put the 60 in the lead column BUT, the hardness is 20! I have tried every way of entering it starting with the 60, the 40, no matter how you do it it comes up to 20 as the hardness. Now, this is not just a one or two number difference, this is substantial. And we are only talking two ingredients, not a complex mix.

[Rich/WIS]

Tin is useful to improve castability but as noted above is not the ideal hardening agent. Antimony is your friend if you want to increase hardness. Have found that mixing one pound of lino with three pounds of lead will produce an alloy that is approximately one percent tin and three percent antimony, about 11-12 BHN. This is a 96/3/1 alloy, about the same as COWW with one percent tin. Only pure lead I have is saved for RB in a ML so use range lead instead which gives a bit harder bullet since the range lead has about two percent antimony and a trace of tin. Most of my 45 ACP shooting is with range lead in low velocity SWC target loads and have even used it in other pistol calibers with low to mid range loads with no issues.

[PBaholic]

Here is another interesting quirk about the alloy calculator. If you look at line #18 you will see 40/60 solder with a hardness if 15. Ok, now go down to the lines at the bottom that are marked "custom alloy" and type 40 in the tin column and hit enter. It will automatically put the 60 in the lead column BUT, the hardness is 20! I have tried every way of entering it starting with the 60, the 40, no matter how you do it it comes up to 20 as the hardness. Now, this is not just a one or two number difference, this is substantial. And we are only talking two ingredients, not a complex mix.

Take a look at my Pb Sn chart. It isn't a straight line. If you chart what comes out of the alloy calculator, it's a straight line. It's not possible to create a simple formula to emulate this.

The calculator is based on a formula that Rotometals uses, but it is only close to accurate in the linear part of the graph, where the output is between 11 and 14.

You can create a formula anywhere you can draw a straight line on the chart, using Y=MX+B. https://www.mathsisfun.com/equation_of_line.html

[Mitch]

PBaholic thanks for posting the chart showing the curve on the hardness. I would imagin the chart for sb would be similar.

[PBaholic]

PBaholic thanks for posting the chart showing the curve on the hardness. I would imagin the chart for sb would be similar.

Sb is harder to work with. You can't simply cut off a chunk, and melt it in.

I've made 2 Pb:Sn:Sb alloys that originally hardened, then got softer over time:
95:4.9:0.1 - Was BHN 8 at 1 day, 9.2 at 7 days, 8.8 at 30 days and 8.5 at 60 days.
91:8.5:0.5 - Was BHN 11.5 at 1 day, 13.2 at 7 days, 12.6 at 30 days, and 12.2 at 60 days.

I've been reading about equal amounts of Sn and Sb, but no one had any data about hardness, so I made an alloy of equal SnSb and mixed in PB amounts to get 99:0.5:0.5 to 80:10:10, and tracked the hardness over 2 months.

I've been shooting the PC'd 99:0.5:0.5 in my 45ACP and 45 Colt, that has been aged from a few days to a few months, and so far have found no problem with any them. I'm thinking this is gonna be my new alloy. This alloy pours and fills well, although my 230gr are coming out about 240.