Lead-free bullet casting alloy
- Thread starter Ian
- Start date
Ian
Notorious member
Looks like I wasn't paying attention to the ternary diagram I posted. Sb/Sn only precipitates out into the liquid solution first up in the far corner of a 5% Sb mix. At lower concentrations it appears to form along with the eutectic alha and beta phases.
So what we get first is pure Bi freezing out of the liquid, then Sn + Bi(1), then Sn + Bi(1) + Sb/Sn starting to form just above the boiling point of water. That last bit of tin and bismuth with Sb/Sn precipitating into an eutectic, solid solution must be what I see oozing out of the sprues.
If I have that right, it looks like the primary phase will consist of 88-(57% X 12%Sn) = 73% Bismuth freezing first in a liquid Bi/Sn/Sb solute, then the eutectic 14.25% Bi/11.25% Sn freezing along with .75%Sb/.75%Sn in the final phase.
That's a LOT of pure Bi crystals.
You can sure tell the difference that tin makes to grain size by adding only a slight bit of Sn, so it must be seriously decreasing the amount of free Bi that is crystallizing out above the eutectic Bi/Sn concentration.
So what we get first is pure Bi freezing out of the liquid, then Sn + Bi(1), then Sn + Bi(1) + Sb/Sn starting to form just above the boiling point of water. That last bit of tin and bismuth with Sb/Sn precipitating into an eutectic, solid solution must be what I see oozing out of the sprues.
If I have that right, it looks like the primary phase will consist of 88-(57% X 12%Sn) = 73% Bismuth freezing first in a liquid Bi/Sn/Sb solute, then the eutectic 14.25% Bi/11.25% Sn freezing along with .75%Sb/.75%Sn in the final phase.
That's a LOT of pure Bi crystals.
You can sure tell the difference that tin makes to grain size by adding only a slight bit of Sn, so it must be seriously decreasing the amount of free Bi that is crystallizing out above the eutectic Bi/Sn concentration.
CZ93X62
Official forum enigma
I have been following the progression of information over the past week, but could not offer comment or gratitude for all of the work that has been done during this venture. I was stuck with a travel laptop puter that could only manage "Read Only" mode for the duration of the trip. I will readily admit that about half the scientific content is a few notches above my pay grade, but I think I have absorbed enough of what is needed to make this casting process do the right things. Again, thanks to all that have contributed time, effort, and sweat to blazing this trail. It will enable me to hunt again with treasured family heirlooms that the stupidity and simple-mindedness of bureaucrats in cubicle farms in Sacramento relegated to collectible or range gun status.
Spindrift
Well-Known Member
For those interested in the properties of bismuth, I found this old article interesting. I’ve had it downloaded on my pad, but don’t know how to upload it... here is a link I found
newixfrancia.com
Properties of lead-bismuth, lead-tin, type metal, and fusible ... Télécharger les documents complets pdf gratuitement | newixfrancia.com
Téléchargement Properties of lead-bismuth, lead-tin, type metal, and fusible ... pdf Documents et fichiers, Tous les fichiers liés Properties of lead-bismuth, lead-tin, type metal, and fusible ....
Hello I’m new to forum and I cast 5 pounds worth of the rotometals lead free bullet alloy the other day for 38-55. I’m new to casting and it took a while to figure out why I couldn’t get a good drop, I was way too hot.
After throwing back every 3rd one I ended up with respectable bullets, but they did sweat some since I air cooled and after reading through here I was probably running too hot with the mould.
I was wondering if there are any updates or tips before I load these to start load development. If all goes well I plan to cast 45-70, and a couple muzzleloader round balls for hunting and plinking here in ca
Thanks
After throwing back every 3rd one I ended up with respectable bullets, but they did sweat some since I air cooled and after reading through here I was probably running too hot with the mould.
I was wondering if there are any updates or tips before I load these to start load development. If all goes well I plan to cast 45-70, and a couple muzzleloader round balls for hunting and plinking here in ca
Thanks
Ian
Notorious member
@mdaddow, everything you need to know is here:
www.artfulbullet.com
Casting with Rotometals Lead Free alloy
Here's my experience based on three pounds of metal and two casting sessions, so there's no way I've mastered this stuff but I did learn a few things which might help the next person. The alloy in question is the new 87.25Bi/12%Sn/.75%Sb alloy we developed to mitigate brittleness as much as we...
www.artfulbullet.com
Thank you that write up helped a lot@mdaddow, everything you need to know is here:
Casting with Rotometals Lead Free alloy
Here's my experience based on three pounds of metal and two casting sessions, so there's no way I've mastered this stuff but I did learn a few things which might help the next person. The alloy in question is the new 87.25Bi/12%Sn/.75%Sb alloy we developed to mitigate brittleness as much as we...
Thermal conductivity of bismuth is 8 times less than tin, so basically an insulator. SbSn is identified in solid electron microphotos so it does exist - under certain conditions of cooling. From the reading about it I've done, it is formed about solidus, then mostly decomposes, depending on cooling. Has a lot to do with the solubility in the 'base' metal.
CZ93X62
Official forum enigma
I did get a return E-mail from Barnes Bullets (Ryan Farr) concerning leade clearances on their Varmint Grenade bullet line. He advises that start clearance is at .020", and I assume he implies that adjustments from that start should be made by widening that clearance as needed. This differs from their Manual's recommendations for their TSX and TTSX bullets, where .050" is the minimum suggested clearance, and expanding that to .100" or more as accuracy dictates. FYI, for those other unleaded bullets.
Don't intend to do this metal but thinking about it, Casting IMHO the mould needs to be held closed while cooling and sprue cut early (no smear). That will allow the cooling alloy to grow in the base, preferably vs the body. Any 'bump' on the base should be symmetric and not cause a shooting problem. I've shot 30 cal really hard PB (~36 BHN) and got near MOA @ 100 (145gr @ 2100 fps). IMHO the base wasn't flat as I cut the sprue when it was hard.
CZ93X62
Official forum enigma
The Lee pot and a few other items arrived from Bwana Larry's Evil Empire yesterday. Scheduled arrival date was 12/15, so the order arrived in 6 days. Props to MidwayUSA for cranking the order out during the holiday rush.
In other Unleaded Bullet News--Speer is having a half-price sale on their Condor Cuddler 30 grain .224" RNHP bullets. Those might be just the thing for the 22 Hornet, so I snagged 3 boxes to do a thorough test-run head-to-head against their Barnes counterparts of the same weight. Speer gave free shipping,too--so I added a box of their 43 grain non-toxic spitzers meant for 223 and 22-250 for further shoot-offs with the Barnes 36 and 50 grain Solid Red Rat Rippers. 296/H-110 seems like the go-to powder in 22 Hornet for the Barnes critters, so I will need to scrounge up some of that.
In other Unleaded Bullet News--Speer is having a half-price sale on their Condor Cuddler 30 grain .224" RNHP bullets. Those might be just the thing for the 22 Hornet, so I snagged 3 boxes to do a thorough test-run head-to-head against their Barnes counterparts of the same weight. Speer gave free shipping,too--so I added a box of their 43 grain non-toxic spitzers meant for 223 and 22-250 for further shoot-offs with the Barnes 36 and 50 grain Solid Red Rat Rippers. 296/H-110 seems like the go-to powder in 22 Hornet for the Barnes critters, so I will need to scrounge up some of that.
CZ93X62
Official forum enigma
Ah, these all-copper or composite bullets are still terra incognita for me to a large extent, and I'm not ready to free-lance with them quite yet. That goes especially for MP-300, which I have zero time-in-grade with. Two unknowns at once? NOPE. I'll play it like it lays for now.
I might try casting some #225438s with the Unnatural Metal, too.
I might try casting some #225438s with the Unnatural Metal, too.
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fiver
Well-Known Member
it's just Alliant's pile on the H-110 bandwagon.
in the last few years thing have changed, but not really.
Hodgdon and Alliant got into this thing where they overlapped the other guy's products in a bid for king of the hill bragging rights.
target-blue-green-unequal-clay dot, 20/28, universal, and the MP series of powders are all back and forth copies of something else.
the first four are already being phased out, because they missed the mark in both price and performance [based on the marketing promises]
the Enduron and CFE series of powders are all just the newer base stocks that will eventually replace the old standby's as the EPA gets unleashed on the powder industry here in the states.
[you know so we can become ISO certified like our European counterparts]
anyway,,, their great claim is more in the washing process that reduces waste [and the type] going downstream, rather than them actually being a better powder.
look where they all are starting to fall on the burn charts, 3031-4895-4350-4198-335 etc. all have a new Enduron or CFE type counterpart,, or will in the near future.
watch when powders are available and see how many of the old standby powders are now once again [for the 4th time] newer 'cleaner burning' powders.
in the last few years thing have changed, but not really.
Hodgdon and Alliant got into this thing where they overlapped the other guy's products in a bid for king of the hill bragging rights.
target-blue-green-unequal-clay dot, 20/28, universal, and the MP series of powders are all back and forth copies of something else.
the first four are already being phased out, because they missed the mark in both price and performance [based on the marketing promises]
the Enduron and CFE series of powders are all just the newer base stocks that will eventually replace the old standby's as the EPA gets unleashed on the powder industry here in the states.
[you know so we can become ISO certified like our European counterparts]
anyway,,, their great claim is more in the washing process that reduces waste [and the type] going downstream, rather than them actually being a better powder.
look where they all are starting to fall on the burn charts, 3031-4895-4350-4198-335 etc. all have a new Enduron or CFE type counterpart,, or will in the near future.
watch when powders are available and see how many of the old standby powders are now once again [for the 4th time] newer 'cleaner burning' powders.
fiver
Well-Known Member
i got to thinking about the 'coating' for these if anyone is still playing.
there is/are alternatives.
hi-tek is a little lower temp.
there is also powder paint, they use it for coating jig heads and can be cured with a heat gun.
a real viable but largely unexplored avenue is plain old testors acrylic paint like you'd use for a plastic model, it sticks to lead just fine.
anyway the key seems to be a coating that doesn't harden off too much otherwise when the bullet takes a dent the paint just flakes off.
stuff like spray on moly, and certain ceramic sprays work just fine on jacketed bullets, they'd have an application here also.
there is/are alternatives.
hi-tek is a little lower temp.
there is also powder paint, they use it for coating jig heads and can be cured with a heat gun.
a real viable but largely unexplored avenue is plain old testors acrylic paint like you'd use for a plastic model, it sticks to lead just fine.
anyway the key seems to be a coating that doesn't harden off too much otherwise when the bullet takes a dent the paint just flakes off.
stuff like spray on moly, and certain ceramic sprays work just fine on jacketed bullets, they'd have an application here also.