Thread: TIG Brazing - Manganese vs Silicon Bronze?

Along my journey into TIG, I've come across brazing with silicon bronze for joining dissimilar metals, which seems like an interesting thing to try out. The only crowd with any kind of range of TIG rods are Gasweld, so I reluctantly wandered in to see what they had. Despite the rack having labels and prices for silicon bronze rods, there were none, only manganese bronze.

The bloke behind the counter said he doesn't bother stocking silicon bronze, with no explanation as to why.

Can't find much on the net about manganese bronze, unless it's called something else in other markets. Anyone know the differences?

Don't remember what manganese bronze is, but as far as silicon bronze goes, have you tried an industrial supplies place? Quick google showed me there's a place (among others) called M&G industrial in Fyshwick, who seem to stock Cigweld, WIA, Miller and Lincoln, I'd imagine they'll have some. I bought mine from an industrial supplies place very similar down here in Melbourne, they carry all manner of TIG and oxy rods (IIRC silicon bronze rods are the same for TIG and oxy?), as well as lots of other useful stuff...

Yep, know the shop well - was there last week. They can be a bit pricey, but you're right, they probably have silicon bronze rods. However, as the guy at Gasweld seemed to think it was quite sensible that they didn't stock silicon bronze, I was wondering whether manganese might be a direct substitute or something.

These details were taken from a CIGWELD gas welding heating and cutting hand book. Sorry I don't have one on TIG welding rods.
Comweld Manganese Bronze has a blue color marking and is free flowing for producing high bond strength on cast and steel.
Comweld Silicon Bronze has a canary yellow color marking, CUSILMAN is a copper alloy rod containing silicon and manganese. Suitable for Oxy welding and TIG welding of CUSILMAN or EVERDUR, which is a sheet.
Hope this helps
Kryn

Originally Posted by RustyArc

Along my journey into TIG, I've come across brazing with silicon bronze for joining dissimilar metals, which seems like an interesting thing to try out. The only crowd with any kind of range of TIG rods are Gasweld, so I reluctantly wandered in to see what they had. Despite the rack having labels and prices for silicon bronze rods, there were none, only manganese bronze.

The bloke behind the counter said he doesn't bother stocking silicon bronze, with no explanation as to why.

Can't find much on the net about manganese bronze, unless it's called something else in other markets. Anyone know the differences?

You caught my interest with this question, so I did a little digging. Generally speaking, manganese bronze has a lower melting point than silicon bronze by a little over 100°C, and a higher tensile strength than silicon bronze by about 20%.

Whether it can be used as a substitute in TIG brazing though, I've yet to find an answer.

Cheers,... Jon.

Ok, I've found some more information that might be relevant:

Silicon bronze has around 1.5-2% Zinc, whereas Manganese bronze has 25-30% Zinc.

I don't know if you have ever tried to TIG galvanised steel before but it's a major PITA! The Zinc turns into powdery yellow/white cobwebs (Zinc oxides, I assume) and blows up all over the place.

So yeah, I haven't tried using Manganese bronze with TIG, but with that in mind I'm not in any hurry to either.

Cheers,... Jon.

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Originally Posted by Jonno_G

I haven't tried using Manganese bronze with TIG

Reading a few manufacturer's spec sheets, it looks like manganese bronze is designed for Oxy only, which is probably why I couldn't find anything about it and TIG.

From memory silicon will flow better than manganese. I only have experience using them with oxy though. The rods i have are fluxed manganese Boss Weld branded, the were $62 for 1kg. M&G do have a bunch of TIG rods just inside the door, to the left of the door as you walk out.

A bit late in commenting, but I can guarantee you that manganese bronze will not work with TIG. Tried it once and the Zinc just burns and splatters out all over the electrode, shroud and the poor unfortunate holding the torch. Tig brazing seems reasonably popular in the US, but comparatively rare in Australia. I'd like to have a play with it myself one day.

Originally Posted by Karl Robbers

A bit late in commenting, but I can guarantee you that manganese bronze will not work with TIG. Tried it once and the Zinc just burns and splatters out all over the electrode, shroud and the poor unfortunate holding the torch. Tig brazing seems reasonably popular in the US, but comparatively rare in Australia. I'd like to have a play with it myself one day.

It's definitely worth playing around with, I use Silicon Bronze to TIG braze reasonably often and it flows very nicely - the main thing is not to overdo the heat as you don't want to start melting the base metal. Nickel Bronze and Manganese Bronze are a whole world of hurt as others have said - the Zinc plays havoc with the tungsten, the gas cup and the fumes are horrendous!

I did find some silicon bronze rods at the industrial supply shop mentioned earlier. The pack the guy picked out was $45, which is about what Gasweld charge for 1kg - they're not cheap rods. It was only when I walked out I realised it was a 0.45kg pack

I've had a few goes with it on steel and copper. I think I'll skip the latter until I've sorted out the former, as getting used to copper's behaviour is a bit of a challenge. I'm finding steel hard enough - this idea of getting the filler rod hot enough to flow, but not melt the base metal is easier said than done. I think I might have to use the foot pedal (I've been running fixed amp settings so I get an idea of what a certain amp setting means).

Originally Posted by RustyArc

The pack the guy picked out was $45, which is about what Gasweld charge for 1kg - they're not cheap rods. It was only when I walked out I realised it was a 0.45kg pack

Ouch.

Originally Posted by Karl Robbers

A bit late in commenting, but I can guarantee you that manganese bronze will not work with TIG. Tried it once and the Zinc just burns and splatters out all over the electrode, shroud and the poor unfortunate holding the torch. Tig brazing seems reasonably popular in the US, but comparatively rare in Australia. I'd like to have a play with it myself one day.

TIG brazing is definitely a nice trick to have up your sleeve, I've used it for a few things over time. My favourite one was when I made an adaptor to run a water cooled torch on my Kemppi, which previously used a gas through power connection. Made the adaptor in two (or maybe 3 even) pieces of brass, then silicon bronzed them together. Even almost colour matched, especially now after 5 years or so!

Originally Posted by RustyArc

I did find some silicon bronze rods at the industrial supply shop mentioned earlier. The pack the guy picked out was $45, which is about what Gasweld charge for 1kg - they're not cheap rods. It was only when I walked out I realised it was a 0.45kg pack

I've had a few goes with it on steel and copper. I think I'll skip the latter until I've sorted out the former, as getting used to copper's behaviour is a bit of a challenge. I'm finding steel hard enough - this idea of getting the filler rod hot enough to flow, but not melt the base metal is easier said than done. I think I might have to use the foot pedal (I've been running fixed amp settings so I get an idea of what a certain amp setting means).

If you have AC on your machine, give it a go. Helps to get a little more heat in with less melting of the parent metal. The other thing that can help is pulling back off the surface a bit with the TIG, use the arc a bit more like an oxy. It certainly takes a little practice though!

And yes, they're not cheap, but you generally won't use them up very fast, and as mentioned above, they can be an excellent trick to have up your sleeve for some odd jobs.

Originally Posted by Jekyll and Hyde

TIG brazing is definitely a nice trick to have up your sleeve

I certainly like the flexibility of being able to join dissimilar metals, and do joins at a lower temperature to reduce distortion.

If you have AC on your machine, give it a go. Helps to get a little more heat in with less melting of the parent metal. The other thing that can help is pulling back off the surface a bit with the TIG, use the arc a bit more like an oxy.

So far I've been using Jody's suggestion from his welding tips and tricks page - TIG Welding/Brazing with Silicon Bronze - DC pulse set to 33 pulses per second 33% on time 33% background amps. What he never mentions in his video is what peak amps he's using - obviously it'll vary depending on what you're welding, but a starting point would be nice. He does mention AC, but at 90% EN, which seems mighty close to DC.

I don't really like Jody's 33. I tend to bump my pulse way up. 150, 250, 500, however far I can be bothered turning the dial. That's for focused arc and overall reduced heat. Or 1pps for open root slow pulse.

I use a calculator thing to work out the overall amps with pulse on. This gives you a starting point.

def pulse(peak, background, main):
return peak / 100 * main + (1 - peak / 100) * background / 100 * main

This gives you a starting point. peak is the peak time in percentage, e.g. 33.
background is the percentage of main amps, e.g. 33
main is the amp setting on the main dial, e.g. 80

A common setting for me might be 75% peak time, 25% of main, 100A so I'd feed in to my calculator thing pulse(75, 25, 100) and it'll give me 81.25A average as the result. Of course, different pulse characteristics completely change the behaviour of the weld. Those 1pps settings you can bank on it feeling more like you get the full main amp setting with adjustable freeze time. But for high pulse rates it works. I don't tend to use it much, more like I know what I want in main amps if I didn't have pulse, use that figure and then just bump it up 20-30A and use the pedal to modulate if required.