Brass- bronze, facts and metal bending

[Stelios_Rjk]

Hi guys,

I am writing this post because I get some experience by experimenting and breaking parts I believe you will find it useful.

Brass-Bronze.

Brass is an alloy mainly consisting of Cu-Zn and it is usually yellow.
Bronze is an alloy mainly consisting of Cu-Sn and its color is usually close to the color of copper.

While restoring a Seagull I needed to bend a piece metal, brass or bronze. As I am not sure about the alloys I tried to bend I will use the colors when polished. Red or yellow.
I tried to bend yellow rods to form old type of thumb screws. After several experiments and broken rods I realized that it has to be glowing red when you try to bend it. The feeling is like the rod want to bend on its own. No serious effort. In case it requires effort and you continue pushing, it will probably brake. Try it to a piece of metal that you don't mind destroying it.

Let's go to the drama. A deformed bronze (red alloy) skeletal type transom bracket. Deformed due to damp package on shipping.
I thought the same method would work. Glowing red etc.. NOPE! It snapped like a carrot. It was awful and I was frustrated.
I went to a experienced welder to fix it. He did a nice job and I take care of the details. Satisfying result, OK as much as it could be.

I tried again on a red alloy part from a Seagull. Glowing red, same result, started cracking.


So, to come to a conclusion. Yellow parts can be bent while glowing red. Red parts, do not touch them!!!

[Keith.P]

It will all bend if you get it hot enough, cast aluminium can break easy as its a little age hardening to start with, depends on the part, but I suspect you could anneal the part and it work cold.

[Gannet]

Stelios,
I am sure that you are aware that materials vary in their ductility. This is often expressed as an elongation percentage at failure.
Brasses and Bronzes exist in hundreds of different specifications, so it is impossible to quote a value which is correct for the parts that you have been bending.
However, Brass might have an elongation value of, say, 30%, whist Bronze might have a value of, say 5%. I believe that the difference is due to their crystal/grain structure.
The condition of the material is also significant. Brass, for example age and work hardens very readily, but is easily annealed by heating to red heat and then cooling rapidly by quenching.
Hope this helps.
Jeremy

[Stelios_Rjk]

These are observations through experimenting. Not general rules. Certainly metals vary in their ductility and annealing should work. For example annealing works fine in used copper gaskets but in "yellow" rods it didn't work for me.

[Charles uk]

The brass "L" shaped transom screws I made for John, were heated to dull red then allowed to cool gently to prevent any grain structure changes from quenching, then cold worked to shape, with no problems.

Coming from an industrial country we have the benefit of large amounts of "how to" literature available, like Kemp or Machinerys in our native tongue, but there must be something similar in Greece, Stelios.

I've never seen brass worked hot.

How was your transom bracket welded Stelios? I have a broken one.

[Oyster 49]

Breaking a skeletal bracket ouch!

[Stelios_Rjk]

Yeap, worst feeling ever, especially as it snapped without a warning.

About the welder. He is specialized in Tig-Argon welding but I don't know what method did he use. When he showed the parts he said that this is "copper", meaning that it's not brass.
The other useful info I get is that he didn't use borax as a flux. Where the welding occur, the color is very similar to the original.
I could try to ask him how did he do it but not sure what answer I will get due to the secrets of his profession.

[spiderg]

Sounds like he fixed it by probably brazing or silver solder???

[Stelios_Rjk]

I give the welder a call to see what I can get. He told me that he used a tig torch and a copper rod. The thing that he can't reveal is the composition of the rod.
He also told me that brazing would also work but it won't be so strong. Silver soldering would be even weaker than brazing.

[Keith.P]

Tic seems to be one way to join brass, using an aluminium bronze filler rod.

[Collector Inspector]

" It snapped like a carrot"

A wonderful turn of phrase my friend.

B

[Stelios_Rjk]