Brazing cast bronze

[JamieGParticipant @jamieg]

Is it possible to braze/solder cast bronze in your own workshop?

[JamieGParticipant @jamieg]

Hi there,

I received a question from a colleague asking if it is possible to braze/solder a broken cast bronze chandelier.

My first thought is yes (haven't seen the offended part yet). I guessed this could be an interesting argument and possibly get your idea and what type of fluss and rod to use (if brazing is possible at all).

Thanks,

Giacomo /Sweden

[Sub MandrelParticipant @submandrel]

You can silver solder it, proper brazing may be going too far. Choose silver-flow type rods.

I have successfully silver soldered brass many times, even a cast door-handle.

Neil

[JamieGParticipant @jamieg]

Thank you Neil for the tip.

Let see the result.

Giacomo

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Neil is quite correct about bronze and brass being easy to silver solder by ordinary means .

There is a possible difficulty though in that the cast bronze may not be cast bronze . Cast bronze is generally used for more sophisticated higher cost work . Cheap stuff is more usually made from any one of many economy alloys – sometimes plated or chemically patinated to look like bronze .

These are sometimes called in the antique trade spelters or base metals – though neither is correct .

The economy alloys are at best high zinc brasses and at worst melted down sweepings from the foundry floor .

Need to test what you've got before attempting silver soldering – some of the really poor alloys just crumble away when heated .

Genuine bronze is very coppery in colour and fine grained . Brass looks like brass . The rubbish metals are usually very yellow and with noticable coarse grain structure and flaws . Need to look at a newly fractured or cut surface to avoid being misled by oxidation or surface treatment ..

Michael Williams .

PS: Not that common – but there are other series of metals for ' brassware ' goods based on Tin/Lead alloys and even cast iron . Surface colouring can be quite good on some of these but the appearance of a newly cut surface is usually a dead give away .

Edited By MICHAEL WILLIAMS on 04/05/2013 15:36:11

[JamieGParticipant @jamieg]

Good point Michael.

Haven't examined the broken part yet. From the description I got the surface is rough like broken casted iron.

I have the feeling that it might not be an easy fix.

Giacomo

[Sub MandrelParticipant @submandrel]

If Michael is right it might be a job for THIS (not the clutch!)

Neil

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