Why does this calculator have pure lead coming up at a BHN of 8.6? If I put in 10 pounds of pure lead, by itself, the estimated BHN comes up at 8.6, instead of 5 as it should be.
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Why does this calculator have pure lead coming up at a BHN of 8.6? If I put in 10 pounds of pure lead, by itself, the estimated BHN comes up at 8.6, instead of 5 as it should be.
See the previous post(260).
This was helpful
Has anyone tried this?
https://www.youtube.com/watch?v=7Y0raK6_Vbk
May have to try on the next batch.....
catmasher
First of all, thanks to everyone for all the knowledge.
I've been reloading for some time but haven't cast before. My dad always did, and still does. Mostly black powder and some six-guns.
Now, me?...well...I like to shoot and I like to play with things that make it possible for me to shoot more...for less dough.
This, now, led me on a quest for being a cheap-o (cheap-o...er?).
I've found a great site for bullets. $0.082/rd of .223 FMJ BT...not bad. (have to buy 1,000)
This brought me down to $0.18/rd, from $0.42/rd...not bad.
Same place offers defective lead cores at 2.5-3%Sb for about $1.65/lb
I suspect I have a touch of OCD, like elvis ammo. hehe
Anyway, I get ahold of a thing and I have to be on top of it before I can let go.
My dad now, he just melts whatever and shoots it. And that's cool. But, my rifle is high velocity (223) compared to what he loads for.
So, I had to research a bit more and learned about powder coat.
Learned that there's some big differences in alloys...
Seems that stuff needs a little Sn added, so it doesn't pour like a wet dog turd on a cold day.
Learned a ****-ton of stuff...
And the majority of my searches lead back to this forum.
Now, it's been a long time since highschool and my math is rusty, so this took me a while to write.
I apologize (and feel stupid) if someone already did this...but...
Here's a formula for mixing two binary alloys.
N=TOTAL # OF PARTS, WHERE THERE IS ALWAYS 1 PART OF A
D=DESIRED PERCENT
C=CURRENT SATURATION% OF THE BASE ALLOY
A=ADDITIVE%
N=(A-C)/(D-C)
Example: (we'll assume the base is 2.5% antimony because we don't want to have more tin than antimony. A titch more antimony than tin won't hurt though.)
We will approximate lyman#2
D=5
C=2.5
A=30 (super hard alloy)
N=(30-2.5)/(5-2.5)
N=(27.5)/(2.5)
N=11
So, total number of parts=11
10 parts base and 1 part additive, in this case gives 5% antimony. (check it out with the calculator)
Now we need some tin...5%
Simply remove 5% of the base from the total parts and add 5% tin...that's fairly close.
Then take 10% of the amount of tin from the base and add that much to the additive...that's **** close. [so, -10%(5)of base and +10%(5) of additive [in this case}]
But, in reality, you can just figure what 5% of the total mix is, take that much out of the base, and add in the tin, and that's close enough for what we're trying to do here.
I am having trouble believing my result. I had BNE analyze my alloy as follows: Sn=3.0%, Sb=7.9%, Pb=89.1%. When I run the calculator it takes 36.5 pounds of pure lead to 100 pounds of my alloy to produce 92% Pb alloy or as close to hardball as I can get. Add over 1/3 in weight of pure lead to get a 3% increase in the alloy. Is that correct? What am I doing wrong?
The results you are seeing are correct.
If you add 100 lbs of your custom alloy (3% tin, 7.9% antimony, 89.1% lead) and 36.5 lbs of pure lead, you get the following alloy:
- - - - 136.5 lbs of an alloy with 2.2% Tin, 5.8% Antimony, 92% lead
It sounds funny that if you add that much pure lead that it only raises the lead content by 3%, but think about it like this: In 100 lbs of your custom alloy, there is 3 lbs of tin, 7.9 lbs of antimony, and 89.1 lbs of pure lead. When you add 36.5 lbs of pure lead, there is now 136.5 lbs of the mixed alloy. However, there is still only 3 lbs of tin and 7.9 lbs of antimony.
Here are the calculations.
Tin: 3 / 136.5 * 100% = 2.2%
Antimony: 7.9 / 136.5 * 100% = 5.8%
Lead: 89.1 + 36.5 = 125.6 lbs. 125.6 / 136.5 * 100% = 92%
The lead percentage doesn't jump too high because the custom alloy was already mostly lead.
Let me know if you have any other questions.
Thanks,
- Bumpo628
Does anyone know of a company that will test your alloy and give you a ratio exactly of what you have to begin with.
I have some really good old alloy mix that was passed down to me but not really sure what content it is.
One of the members here (BNE) can do that for you
There is an error in the 070612 Calculator. "Estimated hardness calculated by Rotometals formula: Brinell = 8.60 + ( 0.29 * %Tin ) + ( 0.92 * %Antimony )"
It should be noted that the 8.60 figure comes from Antimonial Lead "Brinell = 8.60 (Antimonial Lead) + ( 0.29 * Tin ) + ( 0.92 * Antimony )" If you plug pure 99.9% lead into the formula, you get a BHN for essentially pure lead of 8.6, rather than 5.0.This needs to be corrected.
Can not get this to load on my new iPad. How do you install it? Had it on my phone and old iPad but the site isn’t carried by the App Store anymore so wouldn’t load.
I've been playing around with the spreadsheet recently. I've got some, quite a bit actually, lead of various analysis that I want to be able to mix up my own alloy. I've input several of the alloys that I've acquired from various sources over the years. For instance, I've got quite a bit of COWW from the 90's and the 2000's. It doesn't vary much so I just averaged the analysis and called it good enough. I've also got about a ton of "range scrap" that I got from a fellow that furnished boolits to metropolitan police and sheriff's departments. It was quite depleted of any Sn or Sb. I've also got about 60 lbs "monotype" that was also depleted of alloying elements but not so severely. In addition I've got a couple of hundred lbs of solder that I salvaged from a pot before I retired. I don't know what it was originally, but it ended up less than 24% tin, the rest lead. Luckily, I also have many spools(25#) of 40/60 solder.
All that to say that when I play around with trying to build up the tin content of some of the stuff I mentioned above. While it sounds like I've got a lot of tin in the solder and monotype, by the time I get a reasonable content of tin, I've exceeded the antimony content. This is not good.
I've never tried to add antimony to alloy but I guess I will have to at some point. I do have several pounds of Bill Ferguson's pulverized antimony and some of his "pink" flux. Glad I saved his instructions. At least the spreadsheet will tell me how much to add so I don't waste it.
The availability of the spreadsheet is a great resource even for those of us who are just trying to get in the ball park. Thanks bumpo628!
How does one handle alloys that have more than trace values of other elements? For example cadmium, chromium. Total other percentages totaling 1 to 2%. It prevents having a source that is 100%.