"John O. Kopf" wrote in message
...
Ned Simmons wrote:

SNIP

One of the most widely used alloys for underwater marine
hardware is 85-5-5-5 (Copper-Tin-Lead-Zinc), usually
pronounced 85-three-5. The ASM Metals Handbook refers to
85-5-5-5 as a bronze. SNIP

I've also seen the same alloy called "Gunmetal" (from British catalogs)

supposed to be easy machining (often appears in steam engine kits)

JK

Among the cast copper alloys, without getting into the numbers, those rated
"excellent" against seawater corrosion are tin bronze; leaded tin bronze;
high-leaded tin bronze; leaded red brass; and aluminum bronze. Silicon
bronze, widely used for boat hardware, is rated "good."

85-5-5-5 is leaded red brass. Also known as "ounce metal." Its Copper
Council designation is C83600, and it gets a top rating for seawater
corrosion resistance.

Without other inhibitors, bronzes/brasses (there is no real engineering
distinction between the two) with 15% or less zinc are not strongly subject
to dezincification. With additions of tin, manganese, and phosphorus, the
zinc content can rise as high as 28% for some seawater-resistant alloys.
It's like steel alloys in the sense that some additives sharply affect the
behavior of others.

All in all, Glen, you've got a real head-scratcher if you're going to use
unknown alloys in your mix. Silicon bronze isn't that expensive, BTW, and
it's very easy to cast. It could be your best solution.

Ed Huntress