Another bullet hardness question

[Jimlakeside]

To quote Cast Bullets For Beginner And Expert SECOND EDITION, 2007 - Joe Brennan. "Arsenic seems to be important in the heat-treating of bullets. Arsenic is essential to increasing hardness by heat treating and quenching as it provides the needed 'interlocking of the lead and antimony crystalline structures.'"

I am assuming that without arsenic pure lead will not harden by water quenching, right?

Can you lessen the BRN of wheel weights (which contain .17% arsenic) by adding pure lead and then water quenching? In other words if I want a BRN of 16 to 18 not 21 or 24 or higher, can I just add a little pure lead to reduce the hardness of wheel weights after they have been quenched?

Thanks.

[Ricochet]

No, arsenic is a good thing, but lots of alloying metals (including antimony) will go into solid solution and age harden by precipitation with or without arsenic.

In any case, it's hard to find lead alloys that are completely arsenic-free.

As for heat treating, it still works when the wheelweights are cut substantially by pure lead. You'll have to experiment to find the hardness you want.

[Calamity Jake]

"You'll have to experiment to find the hardness you want."

And the next batch will be some amount different than the first, but probably not enough difference to make a difference. If that makes any sence.

[cbrick]

Arsenic is NOT required to quench or HT. Arsenic is a catalyst to antimony which is the most common hardening metal used in the metals industry and thus the most common found in what is used in bullet alloys. The metals industry uses arsenic as a catalyst in lead/antimony alloys to increase the final quenched strength (hardness) while keeping the very brittle antimony percentage as low as practical. There are several other metals that can be used as a catalyst other than arsenic but again arsenic is the most common used in the metals industry.

Pure lead could be hardened "a bit" with a trace of arsenic by quenching but an alloy of lead/antimony could be hardened significantly more by quenching or HT. An alloy of lead/antimony AND a trace of arsenic can be quench hardened far above what the percentage of antimony would suggest.

Pure lead will not respond to quenching or HT.

Rick

[runfiverun]

that trace should be near .20 or so iirc
you can also vary your water quenching bhn through temperature control.
[ putting a cooler boolit into the water]
the techniques are nice but consistency is the key. time, rate, pour, etc..

[cbrick]

the techniques are nice but consistency is the key. time, rate, pour, etc..

True but consistency can be controlled by oven HT. All bullets at the same temp, same amount of time from oven to water etc. Also, a convection oven will give better consistency than a conventional cook oven but both will work.

Rick

[felix]

Bismuth might work as well as arsenic, but why use it because of cost if additional weight is not needed? What cbrick says is right on. ... felix

[chunkum]

Since arsenic is added to dropped shot alloys because it enhances the surface tension and the tendancy for the drops to hold together and the shot to round up more, is it possible that variable arsenic content in WWs might explain why some WW alloys fill out moulds OK and others require that the tin content be increased a little bit to attain good fillout? (tin having the opposite effect on surface tension).

Disclaimer: I've never actually proved either of these qualities of arseninc or tin but, from information here and elsewhere, believe these qualities to be as I've stated them. :-D
Best Regards,
chunkum

[Ricochet]

I've thought exactly the same, Chunkum.

[felix]

True. ... felix

[blackthorn]

For a long time I have been under the impression that a small amount of arsenic in an alloy was beneficial in retarding the tendency of an alloy (sans arsenic) to soften over time. (as opposed to an alloy of lead-antimony and tin) Is this not true?

[Naphtali]

. . . a convection oven will give better consistency than a conventional cook oven but both will work.

RickWhy is a convection oven superior? Please identify some well-suited convection ovens.

[runfiverun]

the convections are better because of the way they heat. a regular oven cycles off and on.
and a convection just holds to a constant temp. better by, better flow inside the oven.
they make better cookies too....
and back to the original question. a 50/50 mix,water dropped, should lower your[external] hardness.

[cbrick]

A convection oven cycles the heat on and off also but it has a fan inside it that circulates the hot air so no hot or cooler spots, even heat throughout for the entire time.

http://www.lasc.us/DSCN0169-2.jpg http://www.lasc.us/DSCN0230-2.jpg

The pans on the right each hold 300 35 caliber bullets so I can do 900 at a time.

Any convection oven large enough for your needs should do well, I doubt any brand name would do any better than any other.

Rick

[John Boy]

Jim, here's some help to get your 16 - 18 Bhn bullets without quenching:

Using garden variety WW's with a Bhn of 14.3:
Bhn 17.38 ... 8# lino and 12# WW's

Using garden variety WW's with a Bhn 15.5:
Bhn 18.1 ... 8# lino and 12# WW's

Reason for the two Bhn's for WW's? I have over 800#'s of WW ingots and have found these 2 Bhn hardness's in the multiple batches when melting them

[Jimlakeside]

and back to the original question. a 50/50 mix,water dropped, should lower our[external] hardness.

Thanks for all the relpies. This is the answer I am looking for since it is much easier and faster for me to water quench versus using a layer of towels. I have ample access to pure lead and wws from my local recycling center at $.40/lb. I really don't want to get into ordering linotype from ebay, etc.

This is a great forum. I have learned a lot. Never thought I would be casting my own boolits and having so much fun.