Brazing 18-8 stainless

Halo

Halo

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I need to fix two pieces of stainless together. Can anyone recommend a suitable and cheap rod and flux ?
 
I've looked at brazing, a big lump of, steel, lower temp than stainless, and propane will not cut it. As Thin suggests - welding is the answer - or rivets if its low load and bolts (of some form) for higher loads.

Jonathan
 
Thanks for the information. The reason for brazing is s mate has a high temperature brazing torch. I tried it with a pre fluxed rod and plenty of borax type flux and it worked although it has discoloured.
 
thinwater said:
Welding is probably better. You are not going to reach the suggested temperatures with propane anyway. Stick welding will work >1.5mm, TIG below that.
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I agree with welding. I am not a very neat welder but have used an ordinary stick welder with 316 rods quite sucessfully. As for brazing it is really silver soldering as very few people now use the old brass wire and borax flux brazing technique, Silver soldering is perfectly possible with a propane torch. The temperature required is set by the rods used and 50% silver content rods are quite low enough temperature for a propane torch. The size of the job dictates how big a torch. My own Sievert set has torches from little pencil flame jobs up to burner 2944 which is about 2 inches diameter at the business end and produces a roaring 3 foot long flame. Model numbers have changed, but this is about the same. Sievert 3444K Detail Propane Gas Blow Torch Kit
 
I was going off the recomendations from BSSA. The temps are over 600C, which is asking a lot of propane unless the metal is very thin... which is pretty much the only reason to braze.

My understanding is that the silver solder is subject to dezincification in seawater. I have test brazed SS and aluminum, and tested in a spray tank, and the results were not acceptable. In the cabin or up the mast it would be OK for a good while.
 
thinwater said:
I was going off the recomendations from BSSA. The temps are over 600C, which is asking a lot of propane unless the metal is very thin... which is pretty much the only reason to braze........................
Click to expand...

A propane flame is about 1200 degrees C. Temperature is not the problem. The problem is people who try to use too small a torch. The little torches sold to soft solder domestic plumbing fittings are not man enough for silver soldering anything but very small parts. You need a decent torch fed by a proper propane cylinder and for big jobs the offtake rate of gas will need a big cylinder. I have silver soldered a copper boiler for a locomotive with propane torches, selecting the right size for each stage and a 13Kg cylinder. I have also heated 6mm thick stainless steel to bright red hot (i.e. about 1000 degrees C) in order to bend it.
 
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