brazing a hydraulic line

[etpm]

The difference between oxy/fuel and oxy/acetylene is that the temperature of the oxy/acetylene is higher than oxy/fuel while the oxy/fuel delivers more heat. So even though oxy/acetylene has a hotter flame oxy/fuel has more heat. The oxy/fuel flame is not as concentrated as an oxy/acetylene flame. The upshot is that oxy/acetylene is great for welding steel because of the really hot and concentrated flame, while the oxy/fuel flame is better suited for brazing cost wise. Acetylene is expensive, while propane (fuel) is much less expensive. This is why oxy/propane is a major flame cutting setup. The oxy/propane heats the steel prior to the start of the cut, then the oxygen really starts to flow. Then the oxygen starts an exothermic reaction with the hot steel and the cutting commences. This process allows cutting steel more than 1 foot thick with minimal dross. So the oxy/fuel heats the beginning of the cut and then the pure oxygen starts to actually burn the steel. Of course you don't care about any of this, you just want to braze. Oxy/fuel brazing will be much easier that air/fuel brazing provided your torch is large enough. This is because our atmosphere is only about 20% oxygen. Pure oxygen allows a much hotter flame.
Eric

 

[Shawn T. W.]

Just be aware that the tiny "20 pounders" of oxygen or acetylene are quite small, and use a much smaller connection on top, which you'll probably need an adapter for ...

If cutting with above setup, you'll use almost 3 times the oxygen as the acetylene ...

 

[big bubba]

wrap a wet rag around both ends to be brazed

 

[John0829]

It is getting harder to find anyone with the knowledge to use ox/acetylene, especially that knows how to braze. I should have said knowledge to use it correctly. I have tried to teach my SIL and lets just say it is a work in progress.

 

[Tractor Seabee]

No substitute for the proper part. I have used all types of silver solder. It is really a brazing process. On steel lines you have to use at least 45% silver and the right flux. You have to find the leak then take to pipe section out and flush out all the oil, then clean the area to a polish. Practice some on scrap if you do no not have silver brazing experience. Use an O/A torch with a 000 tip. Easy to overheat thin steel wall tube. This product will with stand high pressures. It is used for fabricating 10,000 PSI marine diesel engine starting air piping which I had a lot of experience with in my younger days.