Howdy,

I needed some 1/4" bolts for an electrical connection, and as the fastener
store was out of 2" long brass bolts, I was sold something called "silken
bronze." According to the fellow behind the counter, they are 95% copper.

Now that I have them home, I can't find any reference to "silken bronze" on
the web, and would like to know a little more about them, including at least
a torque recommdation.

Anyone know what other name these might be called which would yield some
results?

Thanks for any tips,

Jon

On Wed, 17 Oct 2007 14:28:12 -0700, "Jon Danniken"
wrote:

Howdy,

I needed some 1/4" bolts for an electrical connection, and as the fastener
store was out of 2" long brass bolts, I was sold something called "silken
bronze." According to the fellow behind the counter, they are 95% copper.

Silicon bronze - a marine hardware store will have silicon bronze or
Everdur fasteners. McMaster, too.

--
Ned Simmons

"Jon Danniken" wrote in message
...
Howdy,

I needed some 1/4" bolts for an electrical connection, and as the fastener
store was out of 2" long brass bolts, I was sold something called "silken
bronze." According to the fellow behind the counter, they are 95% copper.

Now that I have them home, I can't find any reference to "silken bronze"
on the web, and would like to know a little more about them, including at
least a torque recommdation.

Anyone know what other name these might be called which would yield some
results?

Thanks for any tips,

Jon

Low-silicon bronze. The guy had a bad accent. d8-)

Electrical properties (I'll let you figure this one out): Electrical
conductivity, volumetric, 12% IACS at 20 deg. C (68 F). Electrical
resistivity, 144 n-ohms-meter at 20 deg. C.

For comparison, here's the grade of copper used for high quality wi
Electrical conductivity, volumetric, annealed, 101% IACS at 20 deg. C (68
F). Electrical resistivity, 17.1 n-ohms-meter at 20 deg. C.

What this means is that the electrical conductivity of silicon bronze sucks.
It has about 1/5 of the conductivity of pure aluminum.

--
Ed Huntress

"Ned Simmons" wrote:
On Wed, 17 Oct 2007 14:28:12 -0700, "Jon Danniken"
wrote:

Howdy,

I needed some 1/4" bolts for an electrical connection, and as the fastener
store was out of 2" long brass bolts, I was sold something called "silken
bronze." According to the fellow behind the counter, they are 95% copper.

Silicon bronze - a marine hardware store will have silicon bronze or
Everdur fasteners. McMaster, too.

Ah, okay, now it makes more sense; thanks Ned.

Jon

"Ed Huntress" wrote:

Low-silicon bronze. The guy had a bad accent. d8-)

Electrical properties (I'll let you figure this one out): Electrical
conductivity, volumetric, 12% IACS at 20 deg. C (68 F). Electrical
resistivity, 144 n-ohms-meter at 20 deg. C.

For comparison, here's the grade of copper used for high quality wi
Electrical conductivity, volumetric, annealed, 101% IACS at 20 deg. C (68
F). Electrical resistivity, 17.1 n-ohms-meter at 20 deg. C.

What this means is that the electrical conductivity of silicon bronze
sucks. It has about 1/5 of the conductivity of pure aluminum.

Okay, thanks Ed. He did say the local utility used them alot, although I
don't know if it was for electrical connections or not.

BTW, is that data you posted from an accessible website by any channce?
I'd like to look up brass for a comparison.

Jon

"Jon Danniken" wrote in message
...
"Ed Huntress" wrote:

Low-silicon bronze. The guy had a bad accent. d8-)

Electrical properties (I'll let you figure this one out): Electrical
conductivity, volumetric, 12% IACS at 20 deg. C (68 F). Electrical
resistivity, 144 n-ohms-meter at 20 deg. C.

For comparison, here's the grade of copper used for high quality wi
Electrical conductivity, volumetric, annealed, 101% IACS at 20 deg. C (68
F). Electrical resistivity, 17.1 n-ohms-meter at 20 deg. C.

What this means is that the electrical conductivity of silicon bronze
sucks. It has about 1/5 of the conductivity of pure aluminum.

Okay, thanks Ed. He did say the local utility used them alot, although I
don't know if it was for electrical connections or not.

BTW, is that data you posted from an accessible website by any channce?
I'd like to look up brass for a comparison.

It probably is available online. There are several metals information sites;
I haven't used them for a few years so I can't help there. But other people
here probably know what they are.

I pulled it from a big volume from the American Society for Metals that I
keep at my desk, _Properties and Selection: Nonferrous Alloys and Pure
Metals_, 9th Edition. I only have this thing because I was once Materials
editor for _American Machinist_. It's very expensive. You'll find it in many
engineering-school libraries. It's Volume 2 of the ASM set, which includes
ferrous metals and other stuff.

Silicon bronze is basically a multi-purpose corrosion-resistant bronze. It's
sometimes called "naval bronze," but that's a misnomer. Other bronzes are
more traditionally called naval bronze and they're better in marine
environments. But silicon bronze isn't bad in that regard. Its big virtues
are that it's relatively cheap and it's easy to cast, and fairly easy to
machine. It's widely used for screws in the building of wooden boats. I've
used a lot of it for various jobs.

--
Ed Huntress

On Wed, 17 Oct 2007 15:57:41 -0700, "Jon Danniken"
wrote:

"Ed Huntress" wrote:

Low-silicon bronze. The guy had a bad accent. d8-)

Electrical properties (I'll let you figure this one out): Electrical
conductivity, volumetric, 12% IACS at 20 deg. C (68 F). Electrical
resistivity, 144 n-ohms-meter at 20 deg. C.

For comparison, here's the grade of copper used for high quality wi
Electrical conductivity, volumetric, annealed, 101% IACS at 20 deg. C (68
F). Electrical resistivity, 17.1 n-ohms-meter at 20 deg. C.

What this means is that the electrical conductivity of silicon bronze
sucks. It has about 1/5 of the conductivity of pure aluminum.

Okay, thanks Ed. He did say the local utility used them alot, although I
don't know if it was for electrical connections or not.



BTW, is that data you posted from an accessible website by any channce?
I'd like to look up brass for a comparison.

http://www.matweb.com/index.asp?ckck=1

Jon


--
Ned Simmons

On Wed, 17 Oct 2007 17:52:55 -0400, "Ed Huntress"
wrote:


"Jon Danniken" wrote in message
...
Howdy,

I needed some 1/4" bolts for an electrical connection, and as the fastener
store was out of 2" long brass bolts, I was sold something called "silken
bronze." According to the fellow behind the counter, they are 95% copper.

Now that I have them home, I can't find any reference to "silken bronze"
on the web, and would like to know a little more about them, including at
least a torque recommdation.

Anyone know what other name these might be called which would yield some
results?

Thanks for any tips,

Jon

Low-silicon bronze. The guy had a bad accent. d8-)

Electrical properties (I'll let you figure this one out): Electrical
conductivity, volumetric, 12% IACS at 20 deg. C (68 F). Electrical
resistivity, 144 n-ohms-meter at 20 deg. C.

For comparison, here's the grade of copper used for high quality wi
Electrical conductivity, volumetric, annealed, 101% IACS at 20 deg. C (68
F). Electrical resistivity, 17.1 n-ohms-meter at 20 deg. C.

What this means is that the electrical conductivity of silicon bronze sucks.
It has about 1/5 of the conductivity of pure aluminum.

Right - but they're using Silicon Bronze bolts for the other
properties than conductivity - environmental effects corrosion
resistance, dissimilar metal galvanic corrosion resistance, and the
thermal expansion rate of the bolts will be in the same ballpark as
the copper parts they are bolting together.

The current should be flowing directly between the top face of the
pure copper busbar and the bottom face of the copper lug you have
bolted on top. The bronze bolt is just clamping the two surfaces
together, and shouldn't be carrying that much of the current itself.

-- Bruce --

"Bruce L. Bergman" wrote in message
...
On Wed, 17 Oct 2007 17:52:55 -0400, "Ed Huntress"
wrote:


"Jon Danniken" wrote in message
...
Howdy,

I needed some 1/4" bolts for an electrical connection, and as the
fastener
store was out of 2" long brass bolts, I was sold something called
"silken
bronze." According to the fellow behind the counter, they are 95%
copper.

Now that I have them home, I can't find any reference to "silken bronze"
on the web, and would like to know a little more about them, including
at
least a torque recommdation.

Anyone know what other name these might be called which would yield some
results?

Thanks for any tips,

Jon

Low-silicon bronze. The guy had a bad accent. d8-)

Electrical properties (I'll let you figure this one out): Electrical
conductivity, volumetric, 12% IACS at 20 deg. C (68 F). Electrical
resistivity, 144 n-ohms-meter at 20 deg. C.

For comparison, here's the grade of copper used for high quality wi
Electrical conductivity, volumetric, annealed, 101% IACS at 20 deg. C (68
F). Electrical resistivity, 17.1 n-ohms-meter at 20 deg. C.

What this means is that the electrical conductivity of silicon bronze
sucks.
It has about 1/5 of the conductivity of pure aluminum.

Right - but they're using Silicon Bronze bolts for the other
properties than conductivity - environmental effects corrosion
resistance, dissimilar metal galvanic corrosion resistance, and the
thermal expansion rate of the bolts will be in the same ballpark as
the copper parts they are bolting together.

The current should be flowing directly between the top face of the
pure copper busbar and the bottom face of the copper lug you have
bolted on top. The bronze bolt is just clamping the two surfaces
together, and shouldn't be carrying that much of the current itself.

-- Bruce --

Aha. Well, that should be no problem then.

--
Ed Huntress

On Wed, 17 Oct 2007 14:28:12 -0700, with neither quill nor qualm, "Jon
Danniken" quickly quoth:

Howdy,

I needed some 1/4" bolts for an electrical connection, and as the fastener
store was out of 2" long brass bolts, I was sold something called "silken
bronze." According to the fellow behind the counter, they are 95% copper.

No, no, no. Silken bronze is synthetic, primarily made up of Polyester
Lead, with minor alloys of coppernumium and brass.

--
Death is more universal than life; everyone dies but not everyone lives.
-- A. Sachs

"Larry Jaques" wrote in message
...
On Wed, 17 Oct 2007 14:28:12 -0700, with neither quill nor qualm, "Jon
Danniken" quickly quoth:

Howdy,

I needed some 1/4" bolts for an electrical connection, and as the fastener
store was out of 2" long brass bolts, I was sold something called "silken
bronze." According to the fellow behind the counter, they are 95% copper.

No, no, no. Silken bronze is synthetic, primarily made up of Polyester
Lead, with minor alloys of coppernumium and brass.

--
Death is more universal than life; everyone dies but not everyone lives.
-- A. Sachs

'Been smoking those old Firesign Theater albums? d8-)

--
Ed Huntress

On Wed, 17 Oct 2007 15:57:41 -0700, "Jon Danniken"
wrote:

"Ed Huntress" wrote:

Low-silicon bronze. The guy had a bad accent. d8-)

Electrical properties (I'll let you figure this one out): Electrical
conductivity, volumetric, 12% IACS at 20 deg. C (68 F). Electrical
resistivity, 144 n-ohms-meter at 20 deg. C.

For comparison, here's the grade of copper used for high quality wi
Electrical conductivity, volumetric, annealed, 101% IACS at 20 deg. C (68
F). Electrical resistivity, 17.1 n-ohms-meter at 20 deg. C.

What this means is that the electrical conductivity of silicon bronze
sucks. It has about 1/5 of the conductivity of pure aluminum.

Okay, thanks Ed. He did say the local utility used them alot, although I
don't know if it was for electrical connections or not.

BTW, is that data you posted from an accessible website by any channce?
I'd like to look up brass for a comparison.

Jon

Brass exhibits about 28% the conductivity of copper.
http://www.kp44.org/ftp/ElectricalCo...fMaterials.php

This doesn't necessarily make it a "bad conductor. You just need
more cross-sectional area to get a given resistance. Bolts are much
shorter than wires, and are usually larger diameter as well. And, as
Bruce noted, a bolt often clamps conductors in contact together so the
conductivity of the bolt really doesn't matter all that much.

"Don Foreman" wrote in message
...

snip


Brass exhibits about 28% the conductivity of copper.
http://www.kp44.org/ftp/ElectricalCo...fMaterials.php

But note that low silicon bronze (the material in question) has 12% of the
conductivity of copper. High silicon bronze (2.8 - 3.8% Si) is only 7%.

Red brass is 37%. "High conductivity bronze," also known as "penny bronze,"
is 41%.

Conductivity of copper alloys ranges all over the map. You really have to
check the conductivity of the particular alloy to know what it is.

--
Ed Huntress

Silicon Bronze is used in electrical connectors to maintain strength
at high temperatures. Not, as George points out, because of it's
stellar conductivity.