Lead Alloying Help Or Advise

[hawgfan]

I had a few members on here test some boolits I made, they came up 20 - 25bhn. I was using COWW and Isotope Lead. I was mixing at a ratio of 50/50 and I was also water quenching. I am reloading for 40 sw and I know that BNH will work but it's really not nessecary, If I let them air cool do you think my BHN will still be good for the 40 sw.

Also I forgot to mention, that I let the cast boolits set for 3 weeks before I had them tested.

Since I have everybody attention I have one more quick question. Can I add linotype to my COWW to get the correct tin percentage. If so, how much. I will be just adding it to my Lee 20lb pot. Or is there another way to get my tin, I just have this stuff laying around. I only have about 12lbs., and I wanted to stretch it as far as it will go.

Thanks

[el34]

Linotype has 4% tin. It is also hard, 20-22BHN.

I use it to accomplish both goals of hardening soft lead and supplying tin. I use an Excel calculator to guide me towards a finished alloy I want.

Monotype has 9-10% tin and a hardness of around 30BHN. Using it adds more tin than hardness, sometimes it works out better than lino.

My scientific wilda$$ guess is that your alloy started out about 12BHN.

Do you think you need more tin? Your boolits looked very good, the SWC shoulders were nice and sharp so it looked like you already had enough tin to accurately and completely fill the cavities.

[badbob454]

my guess would be 12 bhn with air cooled ww's and @ 9-10 bhn with 50/50 mix coww/ tin , both should be good for a 40

[knifemaker]

If your alloy is around 12BHN, that should be good enought for your 40 Cal. If your fillout is good coming from the mold, you should not need any further tin. I would cast about 50 boolits of your present alloy and try them out in your gun. You may have a winner already. I run 50/50 clip on wheel weights and pure lead with 1-2% tin added and have shot them at close to 1400 fps in my 41 mag without any leading of the barrel and very darn good accuracy. They are softer then your alloy. The boolit fitting the barrel groove dia. is more important then the boolit hardness to prevent leading and for good accuracy. Yes linotype can be added to increase tin and even hardness if needed. I do not think you need to do that untill you try those 50 rounds first and see what you get in the way of preformance.

[el34]

my guess would be 12 bhn with air cooled ww's and @ 9-10 bhn with 50/50 mix coww/ tin , both should be good for a 40

50/50 coww/tin would sure be expensive! Unless you get free tin.

Have you noticed the powdercoating threads in the Boolit Lube section? No leading, BHN not as important.

[hawgfan]

Do you think you need more tin? Your boolits looked very good, the SWC shoulders were nice and sharp so it looked like you already had enough tin to accurately and completely fill the cavities.

I really didn't have anything to compare them to, so I wasn't sure if they looked good or not. So maybe I am asking the wrong questions. I have about 200lbs. of the mixture you tested for me so, what can I do to lower the BHN, either by adding pure lead or just air cooling them. Thanks again for testing for me.

[el34]

I have never tried casting with a low-tin alloy. When I decided to get into making boolits I learned as much as I could before ever melting my first wheel weight. One of the points was to have between 1 and 2 percent tin, not for hardness or shininess, but for breaking the surface tension of liquid lead so that it will fill in all the fine details within a mold cavity. Sharp edges where they should be sharp.

To be sure of my casting alloy I have always added tin to get 2% while assuming there was no tin in what I was starting with. It's likely some of the time there was some tin, maybe even 1%, but it's hard to tell. Some metal scrapyards have a great analyzer referred to as an x-ray or XRF analyzer. It's handheld and takes a couple of seconds to analyze mystery metal. It then displays all the individual metals by percentage. One 300lb batch of mystery lead I bought there showed it already had 2% tin, that was great to find out.

I think keeping your 12BHN alloy hardness is a good thing but I'm not smart enough to know it's better than getting the same hardness by quenching a softer alloy. Based on what's in the starting alloy, particularly the amount of arsenic, affects how many added BHN points will result from quenching. If you get into powdercoating, the baking process will anneal the boolits and undo some or all of the quench-added hardness.

[bangerjim]

Invest in good hardness tester. I highly recommend the Cabine Tree. That way you will not have to rely on others to do your testing for you and you can play around all you want.

You do not want use 40's that hard......wasting good alloy.

Consider electrostatic gun powder coating. It eliminates the worry of hardness and totally prevents leading without using greasy lubes! All my alloy is now 10-12 with PC'ing.

Check out the stickys on powder coating. You will not be sorry!!!!!!

banger

[el34]

Invest in good hardness tester. I highly recommend the Cabine Tree. That way you can play around all you want.

Consider electrostatic gun powder coating. It eliminates the worry of hardness and totally prevents leading without using greasy lubes! All my alloy is now 10-12 with PC'ing.

Check out the stickys on powder coating. You will not be sorry!!!!!!

banger

^^^^^ that ^^^^^

[el34]

Hawg- send me 20 air-cooled and I'll measure a couple for BHN. Then I'll powdercoat the rest for ya and send them back!

I'll even give you a choice of colors.