David,

The work I have done with Aluminum Bronze is in the casting of CDA 956.
It's about 91% Copper, 7% Aluminum and 2% Silicon. All this was done at a
commercial foundry about 20-25 years ago.

I considered this to be the "best" of the brasses and bronzes that I worked
with in terms of overall strength and use in engineering applications. It's
density is nearly that of any other bronze or iron. In other words there is
insufficient aluminum to "lighten" it. The color is a light gold.

I also considered this the "worst" alloy from the standpoint of difficulty
in casting. It is highly suceptible to shrink defects and easily oxidizes,
forming dross defects. The best preventions are to riser the alloy with the
best possible practice and anticipate a large amount of shrinkage. This
means large risers and large riser necks. The gating should be
non-pressurized, or sprue-choked and use bottom gating and smooth flowing
runners and ingates. Melting should be carefully controlled, drosses
skimmed off before pouring, and the molds should be filled carefully.

If the founding is done well then when the parts are cut off the gating and
risers removed, the metal will clean up well and make excellent looking,
very strong, corrossion resistant castings.

Mark


"David" wrote in message
news:uUzce.1167345$8l.785060@pd7tw1no...
How is the weight?
Is it closer to Aluminium or bronze.
Any use suggestions or observations appreciated.

--
~david

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