Rotometals superhard

GSPguy

Member
I bought some of the super hard alloy to mix with with some pure lead. I have never used this before so I was curious about it’s hardness so I got out the Lee tester and to my surprise it checked pretty soft. I don’t remember the conversion on the dot size but it measured .060. Can this be correct?
 

Bret4207

Undesirable member in absentia, Northern NY
Looking at that link from Glen I'd aim for something around 13-14bhn. Thats about what good old type WW would get you and that worked for 90% of common stuff. If you see the need for a harder alloy it's not hard at all to juice it some, or water drop/heat treat, if (and only IF) you see an actual need for a higher Bhn. Bhn alone will not solve any issues with poor fit, incompatible powders, fouled barrels, etc.
 

GSPguy

Member
Will they harden up with time? I am really thinking about my 1 pound ingots. When I smelt a batch of unknown alloy can I get an accurate reading on them after a given amount of time?
 

Brad

Administrator
Staff member
Not really. When I pour ingots the first ones harden pretty quick due to cold moulds. The next ones harden far slower as the mould is not very hot. Could be a difference of 3 plus minutes.

Ingot hardness really tells us very little.
 

Winelover

North Central Arkansas
Alternate to Superhard/Pure mix............is one part of Roto's Lino to three parts of pure lead. Resulting BHN is 14-15 in three weeks. As tested on LBT hardness tester.
 

Bret4207

Undesirable member in absentia, Northern NY
What exactly are you aiming for? Are you trying to bring straight lead up to a usable point or are you trying to hit a specific Bhn #?
 

GSPguy

Member
I picked up about 700 pounds of pure lead and will be making a few different hardnesses. Doing the math is no issue. I was just curious how hard, super hard was and thought I would check it and was surprised when it checked at about 15.
 

Bret4207

Undesirable member in absentia, Northern NY
Well even the Rotometals site says they offer no Bhn because even they can't test it to get a Bhn. It's 30% Sb. If you know you have pure lead, like you said the math isn't that hard. You will probably want some tin and other elements in there. Ian, Fiver and some others can give you good advice there.
 

Ian

Notorious member
30% Sb/70%Pb doesn't squish with a Brinnel tester in a way that is meaningful to bullet casting. Use it to bring your Sb % up to about three or four, toss in a half percent tin for kicks and be happy. For over 2K fps or 45 KPSI you can water-quench it and/or up the tin % to just below the Sb %. Half #2 alloy (2.5/2.5) is an extremely useful alloy for rifle bullets.
 

Bret4207

Undesirable member in absentia, Northern NY
There ya go, one handy, dandy recipe all laid out. Is this place great or what?!!!!