This has already been noted/addressed. Like Bumpo says - it's the best thing we got right now. It's an alloy calculator not an alloy reduction calculator. Welcome to Cast Boolits also. Good to see new folks.
Thanks again Bumpo.
Wes
Printable View
This has already been noted/addressed. Like Bumpo says - it's the best thing we got right now. It's an alloy calculator not an alloy reduction calculator. Welcome to Cast Boolits also. Good to see new folks.
Thanks again Bumpo.
Wes
The linear formula works pretty well to approximate the alloy-hardness curve over a limited range. As has been noticed, it fails at the boundary. Still, it's a good way to look at how hardness changes as a result of small changes in alloy. Could probably create another formula that worked better for very low concentrations of tin and antimony.
Mark
And, me too, welcome aboard!
Thanks guys.
If you look at the note section, you'll see the formula:
Estimated hardness calculated by Rotometals formula: Brinell = 8.60 + ( 0.29 * %Tin ) + ( 0.92 * %Antimony )
Or in other words:
8.6 + a modifier for tin + a modifier for antimony
What can be learned from this is that antimony impacts hardness about three times more than tin. I bet this formula was derived by experimentation at Rotometals on some of their alloys. They did not test low % alloys, so that is why the formula starts at 8.6.
I've noticed that the formula only seems to be close to the published values when both tin and antimony are over 0.5%. The numbers are more accurate when the tin and antimony %s are close to each other. If you calculate the hardness for Lyman #2 and Hardball, you get 15 for both. Lyman #2 should be 15 and Hardball should be 16.
I hope you guys find the calculator useful. Let me know if anything else is missing or doesn't look right.
Thank you for the explanation and warm welcoming. I should definitely spend more time researching the forum, because I'm very new to the casting. I have an idea to play with very soft alloy (i.e. BHN=7) for my 357 revolver bullets, but not sure how to get below 8.6 using the Rotometal's Super Hard. Is there any specific calculator for that available?
That's too easy :) I have a stash of pure lead which I'd like to utilize.
1 part Superhard to 9 parts Lead should reduce the overall Antimony concentration to 3% which should be pretty close to what you are after. If that is still a bit hard try 1 part to 10.
If you look at the column on the right on my table, you'll see the published values for the different alloys. Chilled shot is the closest alloy that I have found to what you requested. It has 2% antimony and the hardness is 10. You will need to get the antimony lower than that to get closer to 7 if you want to make it out of Superhard and pure lead.
Using this mixture you should get something close:
0.375 lbs (= 6 ozs) of Superhard
10 lbs of pure lead
= alloy with 1.08% antimony
You could also get some stick-on WW lead. It should have a hardness about 6 or so. No mixing required.
My stickons test between 6 and 7, depending on moonphases and such.
Bump.
Bumpo's calculator should be a sticky, IMO.
I saved it on my computer so it is for me
but you are absolutely rite it is very nice
I'm loving this calculator, thank you. It doesn't have to be laboratory-grade for my bullets, just close enough to give me an idea of what to expect if I mix, say, 50 lbs of WW with 50 lbs of range scrap - and then perhaps drop in a 1lb bar of 50/50 solder.
Again, thanks a million :)
Excellent work, this sure saves lots of time.
Thanks very much for making this available :drinks:
Thanks for all of the comments.
I got a request to add silver solder to the calculator. I added a column for silver % and a row for 96% tin, 4% silver solder.
Attachment 39781
As mentioned, this is a GREAT source for the site, especially for us newer folks who are scrounging to get alloy materials together.
Thanks again for your work on this.
Thanks Bumpo! Nice work:-D
Attachment 44585
Thought I'd give this a face-lift and a unit-cost calculator. :drinks:
Lee W - You don't need that hard an alloy for 9 or 40, maybe for 10mm. 98/1/1 is fine for SA. Done both, no accuracy, feeding or leading difference, just more trouble. I did the 95/2.5/2.5 with As, HT (~18 BHN) for 30-30 @ ~2000 fps OK, but for .40 it's too much trouble and $.
Thanks for the nice feature suggestion. I added your concept to my original format and filled in as many prices for alloys as I could find.
I originally intended the alloy calculator to also serve as a reference sheet when printed out. So, the cost calculator was added to the next page as a 'module'. I set the margins so that if it is printed as "portrait', then you get the alloy calculator on the first page and the cost calculator on the second page. If you print as 'landscape', then you get the alloy and cost calculator on one page, and the notes and cost results on the second page.
Attachment 44732
I have an issue with the % values in the upper section for 10:1, 20:1, 25:1, 30:1 etc.
Go here for a complete explanation: http://castboolits.gunloads.com/showthread.php?t=158582Quote:
The answer is in fact 3.85% Tin for 25 to 1 alloy, not 4% Tin.
That is according to Lyman 4th Edition, Cast Bullet Handbook.
They say that 10 to 1 is 9% Tin (1/11 * 100 = 9.0%)
and 20 to 1 is 4.8% Tin (1/21 * 100 = 4.76%. They rounded up to 4.8%)
Based on that, my math was correct and 25 to 1 is 3.85% Tin. (1/(25 + 1) * 100 = 3.85%)
Also, going in another direction I found a quote from a Glen Fryxell article on bullet metals:
Glen wrote, “… For hollow point bullets I have grown fond of using 25-to-1 alloy (6 lbs pure lead with ½ lb. of 50/50 solder)…..”
The math on that shows Glen’s 25 to 1 recipe to be 3.85% Tin as well.
Live and Learn! Learn to trust what you know!
So, Rotometals 25 to 1 is not the classic 25 to 1 alloy of old, it is actually 24 parts Lead to 1 part Tin, with 4% Tin!
So,
10 to 1 alloy is 1/(10+1) * 100 = 9% Tin
20 to1 Alloy is 1/(20+1) * 100 = 4.80% Tin
25 to 1 alloy is 1/(25+1) * 100 = 3.85% Tin
30 to 1 alloy is 1/(30+1) * 100 = 3.20% Tin
Just a heads-up! I PM'd you as well. I am pretty sure that I am correct. If I am not, please let me know!
Thanks,
DC-1