Antimony and Hurst Flux
When I first began handloading, one
of the old hands who met each Saturday morning at Cal Higginss gun shop advised me
to follow one simple precept consisting of three short words: Always start low!
As new to the game as I was, those words made sense to me then. They still do. Of course,
the old gent was referring to powder charges, but why it never occurred to me to apply
that same cautious approach when alloying bullet metal, I cant say - but
circumstances reminded me of his advice just last week.
A friend gave me a bucketful of
range scrap. Consisting mostly of handgun bullets, it was apparent most had been swaged
from very soft mixes. Since I was about to embark on a series of tests requiring cast
bullets to endure muzzle speeds of 2,200 to 2,400 fps, the scrap would come in handy, but
it would have to be hardened considerably to be useful.
As luck would have it, right about
that time Bill Ferguson (PO Box 1238, Sierra Vista AZ 85636), who sells bullet metal, sent
some pulverized antimony and a sample of Hurst flux to try - manna from heaven!
Ever make little chunks of antimony
out of big ones - or try to? It can be done, but its a poor substitute for a hobby.
Now, thanks to Mr. Ferguson, nobody has to. He sells antimony that has already been
crushed into small, useful fragments. The accompanying photo shows a small number of them
scattered across a quarter-inch grid. The majority are about 1/8 inch long and wide. So
sized, they are much handier to use and measure.
It doesnt take much antimony
to harden a mixture, so once the scrap liquefied (the electric furnace was set at 600
degrees), a teaspoonful of antimony was added. Next came the Hurst flux.
Bill had cautioned that pulverized
antimony would melt faster if pot temperatures were held down. That proved to be true. He
also recommended sprinkling flux over the mix with the aid of a salt shaker. That advice
Hurst flux is flesh pink, and as I
was to discover, a little goes a long way. I filled a teaspoon with the flux and scattered
the stuff liberally over the top of the melting mixture. Some of the flux turned into a
dark foam, indicating that too much had been used. Eventually, after stirring and
stirring, the antimony particles disappeared and so did the excess flux.
Another teaspoonful of antimony went
into the pot. This time, an old salt shaker was filled with flux and sprinkled over the
steaming metal. It was much easier to control the amount of flux distributed, thanks to
that shaker. As a result, a thin, fairly even coat was spread over the top of the mixture.
After it melted, the alloy was stirred again until all the antimony had been absorbed.
Hurst flux was created especially
for those of us who depend on electric furnaces. It is non-toxic. Theres no
objectionable odor when it melts either. According to Bill, it is most effective when
antimony fragments are no longer than 3/8 inch and no smaller than 1/8 inch. He notes that
larger pieces take forever to dissolve in a melt, while those smaller than 1/8 inch
sometimes solidify into hard balls of antimony and flux. Nothing like that occurred with
the antimony he sent.
As I relearned, whether reloading cartridges
or alloying metals, always start low. If you dont add enough antimony to a mix the
first time, you can always toss a bit more in later. If there isnt quite enough
Hurst flux to cover a mixtures entire surface, scatter a smidgin more on, but be
sure to do it with a salt shaker - it sure makes the task a lot easier.