Brazing stainless steel - what's easiest?

[Chris Green]

I need to mend a small piece of stainless steel, it's essentially a small length of tube (125mm dia or so) with a flange that needs to be re-affixed to a then plate. The original welds (not mine!) were absolute rubbish and have come apart.

I don't have TIG (only MIG and stick) so I think brazing is probably the best option. I have a gas torch which can get it hot enough, so what's the best sort of brazing material to use?

The stainless is probably one or two mm thick and the joint needs to be reasonably strong as it's holding chimney cowl to a chimney.

[Chris Green]

'thin plate'

[Cursitor Doom]

Are you sure you can get it hot enough? What gas will you be using?

[David]

I need to mend a small piece of stainless steel, it's essentially a small length of tube (125mm dia or so) with a flange that needs to be re-affixed to a then plate. The original welds (not mine!) were absolute rubbish and have come apart.

I don't have TIG (only MIG and stick) so I think brazing is probably the best option. I have a gas torch which can get it hot enough, so what's the best sort of brazing material to use?

The stainless is probably one or two mm thick and the joint needs to be reasonably strong as it's holding chimney cowl to a chimney.

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Silver Solder - Easyflo is you still have some or the non-cadmium equivalent such as Silverflo 55

Flux - you will need a flux such as Tenacity 5 which will still be active with prolonged heating.

[Chris Green]

Butane (I think), the slightly hotter of Propane and Butane anyway.

However I'm moving towards Gasless MIG, I didn't realise you can get gasless stainless steel MIG wire.

[Dave Plowman (News)]

I've welded stainless with MIG wire from Halfords. Like much of my welding not pretty, but strong enough for the job.

[Brian Gaff]

Would it not be easier to just get another bracket of some sort. Those brazed joints fall to bits, I had a speaker stand made of brazed SS and that fell to bits indoors! Brian

[PeterC]

At work I used oxy-propane for silver soldering and brazing. The fitters couldn't dp st. st. (it was an electronics factory - not much use for such tings). I tried some sort of 'ordinary' flux (ICR which - 30 years...) and of course it didn't work. Tried cleaning the pieces, applying a paste of the flux, leaving for about an hour and it worked! I never did tell them how I did it, so had to do all the odd bits that came along. I made a cage for a a 1.5 li bottle for my touring bike; it's still intact after tens of thousands of miles use. The frame did have 3 bosses on it - wouldn't have loaded 2 bosses like that, especially on 531.

[FMurtz]

[newshound]

Personally I would try brazing. I *thought* propane was hotter than butane, anyway plenty hot enough for easyflo provided you can box it in with firebrick (I use the vermiculite blocks used for some woodburner stove linings). I don't think I have ever actually needed to braze stainless, but I do have some aggressive fluxes.

[PeterC]

At work I used oxy-propane for silver soldering and brazing. The fitters couldn't dp st. st. (it was an electronics factory - not much use for such tings). I tried some sort of 'ordinary' flux (ICR which - 30 years...) and of course it didn't work. Tried cleaning the pieces, applying a paste of the flux, leaving for about an hour and it worked! I never did tell them how I did it, so had to do all the odd bits that came along. I made a cage for a a 1.5 li bottle for my touring bike; it's still intact after tens of thousands of miles use. The frame did have 3 bosses on it - wouldn't have loaded 2 bosses like that, especially on 531.

[Fredxx]

Propane flame temperature is 10C hotter than butane (in air).