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Phosphor bronze?


#1

Not too long ago, I went down to a local metal salvage/surplus store
and bought a huge sheet of bronze. The man working there referred to
it as “phosphor” bronze, which I just let slide by, stuck in my
thinking that bronze is (only) an alloy of copper and tin. Now I know
better. I’ve searched on the internet for any about
phosphor bronze but haven’t come up with anyting particularly useful
for my application (jewelry).

I’d appreciate any useful, interesting or practical about
working with this particular bronze.

Thanks,
Christine


#2

Hello Christine,

As far as I know about phosphor bronze,it’s an alloy of copper,tin
(up to 5 %) and phospor ( 0.35%).It has a great resiliency,hardness,
and fatique endurance.It’s has a great resistance to corrosion.It can
be soft or hard soldered (with silver).Melting point is somewhere
around 840 �C up to 1030 �C depending on the used alloy’s.That’s
about it.By the way,I used it for casting purpose and this alloy
works great for me.It has a very nice goldlike finish and buffs up
real good.Go for it if you like,but be carefull when annealing it
since phosphor bronze could become brittle when overheaded.I, never
had this problem since I swith off the light when I anneal about any
metal. Regards Pedro Palonso@t-online.de


#3

Phosphor bronze is a very difficult material to work with. It tends
to be springy and it’s hard to machine. The only thing I’ve seen it
used for is piano strings and certain machine parts. But the color is good. Dee


#4

There are many types of bronze, Phosphor, Aluminum, Berillium,
Silica being a few. Then each of these CAN have additional metals
alloys (Everdure vs Herculoy both silica bronzes, the second having
zinc). Try calling Atlas Metals (303-623-0143 or 800-662-0143) and
ask them. Belmont Metals (NY?) would also know. Another place to
ask/look is at the ArtMetal site. Web site and list info follows
this note.

** Atachment Removed **

John Dach


#5

Cristine,

Your bronze contains phosphor, this is used to get harder bronze.
This means that a bearing made from this material can work on heavier
loads than normal casting bronze for instance. I can give specific
details on this material but I have to bring them from my work and
they are only technical. Now what you can do with this stuff. It can
be recasted in every shape. Be aware that you do not over heat this
material otherwise some elements will evaporate. However if you do so
the workability of the material will be better. It can beautiful
polished but will be darken as copper after some time. The only is
thing is that this material is a bit brittle. so big deformations have
to be done step by step. with dull red treatments in between. Further
on is sawing not easy, use a sharp not to fine saw blades, without
using oil or grease as a lubricant. You are working on a material what
is made for sliding with steel.

If you want to know more, let me know.
Martin Niemeijer


#6

Phosphor bronze is springy. Makes the pawl springs in a bicycle
freewheel. The freewheel allows you to coast without pedaling.

Also good for firearm cartridge primers. There you are looking for a
precise fit, with no grease. Mustn’t block the path of a spark
travelling to the powder charge.

Dan Woodard


#7

Thanks to all who responded to my question. I was mostly interested
to know if there was any danger associated with the working or wearing
of phosphor bronze, or if any special precautions needed to be
observed. I have one remaining question, though: What element is it
that evaporates upon over heating? Is it the phosphorus?

Christine


#8

Hello Christine,

Copper has a melting point of 1083 �C or 1981.4� F
Tin								232 �C or  449.4� F
Posphorus						44 �C or  111.4� F

What really happends talking about the metalurgy of the alloy,I don’t
know.Hope that some one could place an addition to the part of info I
already gave. Regards Pedro Palonso@t-online.de


#9

Christine, There are several types of phosphor bronze. The phosphor is
use to make the material better casteable and works as an antioxidant.
The amount of Phosphor varies between 0.2 to 2.5%. This material is
added to the liquid copper and tin to remove the oxygen and tin
oxide.These oxides are bad for the performance of the bearing
material . Above 1.5% the phosphor is working as an alloy and
reinforces the material. If you have this type, and overheat this than
the phosphor get free, but this will burn into Phosphor oxide or
reacts with the tin and copper oxides on the surface. This phosphor
oxide is as toxic as the burning of matches. But when you are melting
ventilation is always necessary. If you wear this material, the
phosphor, copper and tin will get out in such low amount, that his is
negligible for someone’s health. But if you are making rings out of
it, the people with a slightly acid skin or sweaty skin, can get
green,dark spot on the contact surface from the copper. So the contact
surface should be small. no wide bands. This should not stop you to
experiment with this. so make nice thing out of it.

Martin Niemeijer.

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#10

Hello Martin,

I didn’t poose the question but I’ve learned a lot from your addition
about the phosphor bronze and really enjoyed reading your comment.
Thank you for sharing your knowledge .

Regards Pedro
Palonso@t-online.de