DIY Brazing/Soldering.

[Andy in Germany]

I've spent several months looking for someone local who can braze gear lugs on my bike with no success. I've been told that I can't weld under any circumstances because 1: This could damage the tube, especially if it's Chromoly and therefore thin, and 2: Butted joins are only soldered brazed so I risk the tubes dropping out of the sockets.
Given that I have 3 possible frames and other things need brazing onto them, I'm looking into learning to braze myself, as it would also be handy at work. I'm googling but finding it hard to differentiate between electrical/model making soldering, which I can do already if not very well, and the more heavy duty brazing involved in this area, in particular I keep hearing there are different temperature requirements but not what is needed for which application.
Does anyone have any idea of this and where I could start asking questions to figure out how and what I'd need?

 

[wafter]

Good work. Can't much speak from experience but I'd expect there to be a lot of info re. bike-specific brazing on youtube. Paul Brodie's stuff is always worth a watch although I'm not sure if workably explicit.

 

[classic33]

Blow torch, running on bottled gas is going to be your biggest difference.

There are smaller ones that run from gas canisters, but the heat achieved is questionable. They'll also be dearer in gas use.

As for the frame being "only soldered" I doubt that method would be strong enough for its intended use.

 

[Andy in Germany]

Blow torch, running on bottled gas is going to be your biggest difference.

There are smaller ones that run from gas canisters, but the heat achieved is questionable. They'll also be dearer in gas use.

Having looked on YouTube, I see what sort of setup you are talking about. Unfortunately a full setup with gas bottles et c is a bit pointless for what I have in mind. I'll have to look and see what is possible with a cannister.

As for the frame being "only soldered" I doubt that method would be strong enough for its intended use.

My mistake, I meant brazed. In German the same word is used for most brazing and soldering; I just translated it without thinking.

 

[wafter]

Again, limited experience but I think you'll need a proper oxy-acetylene torch to achieve brazinng temperatures - don't think you'll have any luck with the likes of a propane torch.

 

[Andy in Germany]

Thanks. That's kind of back to square one, although it means anyone with such a torch could potentially braze things for me if I provide flux and filler; I'd feared that the equipment would be coinsiderably more specialised.

 

[fossyant]

Other thing to mention is the fumes. The guy that built my best bike stopped frame building in the end as the fumes affected his health.

 

[tom73]

As @fossyant points out before you even think about trying you're going to need the right ventilation.
It's one of the many skill my dad learned along the way working in engineering. It's very much a skilled art.
Propane (thats if you can find any most of placers in Europe deal in butane cylinders) won't work you are going to need a proper oxy-acetylene set up. Your going to also need to learn the basic make up of the metal your working with. They need different temperatures and welding rods. The same go's for the area of frame being welded and the strength it needs.

You're right anyone who welds maybe able to help depends on the leave of skill and what they are use to working on.
You could try your local college they may have some one who teachers it as part of other courses. They may even do classes.
Finding someone looks the best bet getting the right set up for now and again use will be costly.

 

[phil-b]

I may be mistaken but I belive it is also sometimes refered to as Silver Soldering. You could try reserching that term and see if it helps

 

[ren531]

Have a look at Rothenberghger blow torch with a MAP gas cylinder they I think claim to be able to get hot enough for brazing .
I have welded older heavier cromo frames in the past and have been ok but obviously can be risky.