This question must be at least 4,000 years old but I must ask it again.
Is there an inexpensive way to determine if a metal is bronze or brass?

I have a pile of old pump bodies and impellers that I need to melt down
and cast into a seachest. I need to avoid zinc as much as possible.
Pump bodies are usually cast in phosphor or aluminum bronze but
sometimes they are red brass which contain zinc. The high brasses are
easy to spot but red brass and commercial bronze are darned near
impossible to tell by looking. I found a chemical test kit for
identifying copper alloys but it cost about $500. All I want to do is
find the zinc.

Is there a chemical that will produce a visable reaction with the zinc?

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

In article kSNpb.960$62.792@lakeread04,
says...
This question must be at least 4,000 years old but I must ask it again.
Is there an inexpensive way to determine if a metal is bronze or brass?

There is no clear distinction between brass and bronze, at
least not in the way the various alloys are commonly named.

I have a pile of old pump bodies and impellers that I need to melt down
and cast into a seachest. I need to avoid zinc as much as possible.

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. This is the alloy we used to cast all
our stuffing boxes, stern bearings, etc. To the best of my
knowledge, it's what Algonquin, Perko, et al, use as well.

The Metals Handbook shows 85-5-5-5 as one of the most
durable copper alloys in sea water. It is not subject to
dezincification, while some of the other bronzes are.

I'd be nervous about casting any critical part that goes
below the water line from a mystery metal.

Ned Simmons

In article kSNpb.960$62.792@lakeread04, Glenn Ashmore says...

Is there a chemical that will produce a visable reaction with the zinc?

How about melting a sample bit with a torch, and
looking to see if any white zinc oxide comes off
and stains the area?

Jim

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please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
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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

"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

John O. Kopf wrote:

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

You're right. Sounds like leaded gunmetal. Easy to cast and machine.
There is something about the addition of tin that prevents the zinc from
leaching.

I am beginning to see that the line between brass and bronze is so fuzzy
that the only real difference seems to be the name. Red brass can be
94% copper and 6% zinc while phosphor bronze can be 11% zinc.

Fortunately I do know that about half of my bronze collection is Everdur
silicon bronze with almost no zinc. It is government surplus with the
alloy number CA655/MIL-T6013A cast into it. The miscellaneous pieces
were what I was worried about. It is mostly regular commercial pump
castings.

OTOH, if a pinch of lead, a smidgen of tin and a dab of zinc will
improve the casting quality maybe a lump or two of the less well
identified scrap will help. :-)

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"jim rozen" wrote in message
...
In article kSNpb.960$62.792@lakeread04, Glenn Ashmore says...

Is there a chemical that will produce a visable reaction with the zinc?

How about melting a sample bit with a torch, and
looking to see if any white zinc oxide comes off
and stains the area?

Jim

Thats a good answer. But how much zinc is in the alloy?? And how do you
know if the white oxide is zinc? It got me to thinking about the times when
I was using a blow torch to look at some ores. I forgot all of it but with
a little research you might get what you are looking for in some old
assayers manuals.

Why not just put a test piece in a boiling hot salt solution for a couple
days and see how it looks??