Can you braze a hydraulic line?

[IndyJay]

A coil #9 wire has many uses! Its more feline than coat hangers.

coil #9 "more feline" as in 9 lives?

 

[jaxs]

I didn't think much about it the first time someone claimed to gas weld steel hydraulic line with clothes hangers as filler. After hearing it again I'd like to ask (A) How many others here can and do gas weld steel hydraulic line with clothes hanger filler? (B) Foremost,will one or more of you expand on the proceedure? Does clothes hangers melt at a temperature low enough so there's a margin until line melts or do you melt parent metal as well? How do you prevent damaging or even collapsing line? Is any hanger suitable and if not,how does one tell? Is there filler available at welding supplies that is equal or better? Most everyone is impressed with OP's brazing repair which is a feat to pull off without contaminating inside line. Welding take's things to a higher level that would be good to know for a few other applications.

 

[Egon]

coil #9 "more feline" as in 9 lives?

Ahh. Flexible!

 

[John0829]

Using a clothes hanger ( done it many times ) is the same as using mild steel gas rods, I prefer to use the mid steel rods but clothes hanger are handy if you happen to be out of the other. Using gas is the same as any other welding you have to learn to read the metal to not get it to hot and burn through or not getting it hot enough to stick. Personally I REALLY enjoy gas welding and brazing, the biggie as with any welding is get it CLEAN if you want it to work.

 

[blueman2]

I am a refrigeration tech so I will be applying my practices and tools to this. I will be using an air acetylene turbo torch with a rosebud about the size of your thumb nail. I usually have no problem doing up to inch and an eighth copper with an MC tank. Most of my experience with steel is brazing copper lines into steel king valves on compressors. We use a paste flux on the mating surfaces and then a 45 to 55% silver alloy brazing rod. Or a hollow core brazing rod with flux inside. I will blast the oil out of the tube with nitrogen and then set my regulator to bleed a low pressure feed of nitrogen through the tube while I heat it up. Probably float the high silver and flux combo all over the top of the trouble area because it is runny, and then switch to the 15% silver alloy brazing rod to cap it because it will build up a patch better. Bleeding the nitrogen through the tube while I heat it will eliminate any oxygen in the line that could allow any residual hydraulic fluid to catch fire, and prevent oxidation and pollution on the inside of the pipe. My first challenge is a bit embarrassing, as I attempted to bubble gum the leak first, so I will have to get the epoxy patch off of the area and get it back down to clean metal. I will document what I do and report back in a day or so.

I have brazed a hydraulic fitting with flux coated silver brazing rods. The ones I have seen are coated with either red, white, or blue depending on the mfr. It worked fine

 

[Kschwennsen]

What kind of pressures can a brazed patch handle? I don't know much about brazing but hydraulics run such high pressures that I don't think I would even try to weld on them let alone braze. I would just replace the line with a flexible hose built for hydraulics. It would suck to have it break down "in the field" with no way to get it back to the shop.

 

[Gord Baker]

I am a refrigeration tech so I will be applying my practices and tools to this. I will be using an air acetylene turbo torch with a rosebud about the size of your thumb nail. I usually have no problem doing up to inch and an eighth copper with an MC tank. Most of my experience with steel is brazing copper lines into steel king valves on compressors. We use a paste flux on the mating surfaces and then a 45 to 55% silver alloy brazing rod. Or a hollow core brazing rod with flux inside. I will blast the oil out of the tube with nitrogen and then set my regulator to bleed a low pressure feed of nitrogen through the tube while I heat it up. Probably float the high silver and flux combo all over the top of the trouble area because it is runny, and then switch to the 15% silver alloy brazing rod to cap it because it will build up a patch better. Bleeding the nitrogen through the tube while I heat it will eliminate any oxygen in the line that could allow any residual hydraulic fluid to catch fire, and prevent oxidation and pollution on the inside of the pipe. My first challenge is a bit embarrassing, as I attempted to bubble gum the leak first, so I will have to get the epoxy patch off of the area and get it back down to clean metal. I will document what I do and report back in a day or so.

Save your consumables and time. Buy a new line. You will never get the oil film removed from the inside. Procedure is correct, job is wrong.

 

[ovrszd]

Save your consumables and time. Buy a new line. You will never get the oil film removed from the inside. Procedure is correct, job is wrong.

Go back to the beginning. He described that the machine would have to be majorly disassembled to remove/replace the line. And I think he mentioned he has the new line onhand.

 

[Menagerie-Manor]

What kind of pressures can a brazed patch handle? I don't know much about brazing but hydraulics run such high pressures that I don't think I would even try to weld on them let alone braze. I would just replace the line with a flexible hose built for hydraulics. It would suck to have it break down "in the field" with no way to get it back to the shop.

Back in the day when going thru my apprenticeship in the pipe welding shop we performed burst testing on brazed copper tube and not once did a brazed joint fail at over 5000 psi, typically the tube would fail with a split similar to a frozen pipe.

 

[lpakiz]

Since we are relaying old "war stories" I'll tell you my experience.
i worked for a construction company as a mechanic. (1975?)
One day, the foreman tells me the D8 (Caterpillar bulldozer) has a split in a steel hydraulic line. The line was at least 1" diameter, maybe 1 1/4. Easy place to get at, right above the track, and the split was right on top.
I applied a patch of brazing rod to it. Looked good. The next day, it leaks again. The bronze filler rod had split exactly where the original split was.
I applied another patch of bronze brazing rod, this time about 1/4" thick, 3/4" wide, 3" long. Good looking patch, I used a weaving techinque. That second patch was a thing of beauty.
Next day, leaks again. My beautiful brazed patch was again split right where the original crack was. No problem on the bonding, the bronze flowed on and adhered perfectly. Formed a beautiful bead. Just cracked that nice patch.
So the next day, I melted off the bronze, formed a steel patch from some 16? gauge steel and brazed that on. End of problem.
Conclusion-- the bronze filler rod just didn't have the tensile strength to withstand the pressure. The steel patch did.
Ever since, I've never attempted to repair a split or crack without incorporating a steel patch.