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Thanks. Again, I have only been told and only used a calc for hardening, that's why i asked this question. I didn't think about assuming what the composition might be, as I have always starting my casting with alloys I personally have done.. Your link and advice has put me on a path that I can use, again thanks !
Thanks for your efforts. I continue to learn and that's why I ask. Again big thanks !Quote:
Originally Posted by Kosh75287
Thanks. Again, I have only been told and only used a calc for hardening, that's why i asked this question. I didn't think about assuming what the composition might be, as I have always starting my casting with alloys I personally have done.. Your link and advice has put me on a path that I can use, again thanks !
The answer is in your own question, from the 1970's, "the solution is dilution." Dilute small batches of 16-18 BHN alloy with increasing-in-size batches of BHN-6 lead. Weigh carefully. Mark "failed" batches appropriately. You will find the proper ratio for the chemical constituents in the alloy, if those constituents cause a shift in hardness.Quote:
Originally Posted by HIGHRPM
From "the final batch" (resulting in BHN-12) you will be able to resolve all previous "failed" batches, by calculating the necessary BHN-6 lead "deficiency" of each "failed" batch and adding the difference in BHN-6 lead to each, which will bring every batch (i.e. all 10#'s of BHN-18) to BHN-12. I hope that makes sense.
Spelled out (Example only, not actual results):
Batch One (50% BHN-6)
0.25# (BHN-18) plus 0.25# (BHN-6) results in 0.50# (say) BHN-14.
Batch Two (58.33% BHN-6)
0.25# (BHN-18) plus 0.35# (BHN-16) results in 0.60# BHN-13
Batch Final (example only, 62.29% BHN-6)
0.25# (BHN-18) plus 0.45# (BHN-6) results in 0.70# BHN-12
Batch One, already containing 0.25# BHN-6 lead, needs an additional 0.20# of BHN-6 lead.
Batch Two, already containing 0.35# BHN-6 lead, needs an additional 0.10# of BHN-6 lead.
Etc.
When the Final Batch is known, weigh the remainder of the original 10#'s of BHN-18, multiply by the Final Batch ratio, and add that much BHN-6 lead by weight to the left over BHN-18 alloy.
It might take a little time and a bit of effort, but this level of testing WILL work. Nothing will be consumed. Everything can be converted.
I’ve been down this rabbit hole before. My range scrap tends to be on the harder side. I’d like to reduce the hardness, so I can use it with my rifled muzzle loaders. I never could find a practical way to do it.
The outlined method will work. It requires a suitable amount of a lesser BHN lead alloy (-6, -7, -8, -9, -10 even), and the patience and time to weigh, melt, test BHN, and retest as appropriate. Obviously, it will never work if the "lesser BHN" alloy is already higher than the target BHN, but that kind of goes without saying.
Just to give you a starting point I went into the calculator and I used Hardball which is BHN 16 and I mixed your 10 pounds with 8 lbs. of pure lead and I got a BHN of 12.
Using Lyman #2 I used the same exact formula and got 12 BHN.
So hardball has a lot of antimony and little tin and #2 has has equal of both but the same formula equals 12 BHN so I would say if you added 8lbs. of pure to your 10lbs. of ally you would get real close to what you want. If you want smaller batches just halve it, 5-4 or 2.5-2.
Possibly this article might be of some value to you.
from CAST BULLETS
Col. E.H. Harrison
NRA 1979, p. 90
-=-=-=-=-=-=-=-=-
MAKING BULLET ALLOYS
A lot has been written on bullet metals, but not much on making up
alloys with specific desired properties. Most bullet casters have
scrap and salvage lead alloys on hand which they wish to use. Can you
provide guidance for making up alloys from such metal to get a specific
product?
ANSWER: The following method does this. It is based on two
observations made during long-term investigation of cast bullet alloys
by the staff of The American Rifleman.
1. The characteristic of a bullet alloy which is most fundamental to
performance is strength, indicated by hardness.
2. The hardness of a mixture of usual lead alloys is approximately in
proportion to hardness of the separate alloys in it. This includes
straight lead, Brinell hardness 5, as a constituent.
Hardness of the salvaged alloys to be used therefore must be know. The
American Rifleman has given a simple method for measuring it: "Brinell
Hardness", January, 1969, p. 57; and "Brinell Hardness Measure",
December, 1974, p. 63-64.
The product having desired hardness is obtained by using the metals on
hand in quantities according to the hardness each supplies. One-lb.
pigs cast in the small iron molds sold to handloaders are most
convenient. The following was made up most recently, aiming at a
Brinell hardness of 15 and using three lots of scrap found to be of 20,
17«, and 12« Brinell hardness number respectively. These weights of
each therefore were taken:
WT. BHN
2 x 20 = 40
3.5 x 17.5 = 61
4 x 12.5 = 50
__ ___
9.5 151
The BHN to be expected from this calculation obviously is 151 / 9.5 =
16. The product should approximate this. In this case it actually had
a hardness of 16.5. Alloys made up by this method regularly show a
slightly greater hardness than their proportions indicate, which can be
allowed for in the make-up or accepted as being tolerably close.
The above proportions were arrived at by a few trial calculations.
These often show that a desired result can be obtained in more than one
way. Thus the method has considerable flexibility. For example, a
calculation with the same three available metals shows that weights of
1, 5, and 3 lbs respectively could be expected to produce an alloy of
(1x20 + 5x17.5 + 3x12.5) / 9 = BHN 16, close though a little harder than
wanted. If only the last two lots of scrap were on hand, 5 and 4 lbs.
of these could be expected to give (5x17.5 + 4x12.5) / 9 = 15.5,
practically the same as the alloy made above.
Thus a few trial calculations, with the simplest kind of arithmetic,
indicate at once the combination(s) of available metals which will make
an alloy of specified hardness, within the physical possibilities of
course.___E.H.H.
..........END OF FILE..........
^^^ Same thing I that outlined (in different weights and three alloy hardness). ^^^
Cut it 50-50 with pure, you will be close. Dont over think this stuff.