prep work to silver solder braze loader hydraulic line

[Fuddyduddy1952]

I have a Surplus Center catalog I'm looking at 7 pages of hydraulic fittings.
www.surpluscenter.com
800-488-3407
All you need is steel line that size. I would assume the fittings are good, if you can flare that would be an easy fix.

 

[2manyrocks]

Although I have a flaring tool for HVAC copper lineset, I'm not sure it will handle steel hydraulic line. I may try to redo the brazing, but I'm leaning towards getting a hose fabricated and moving on because of all of the other projects I have to deal with.

 

[etpm]

I wouldn't worry about your copper patch too much because you could always paint it. But steel would be better. In any case your patch looks crappy. I mean the soldering job. If I were you I would remove the patch and start over. You can get small pieces of steel sheet at a good hardware store. Where I live I have two options. The first is available at two hardware stores. They both sell all thread, steel rod, steel tubing, and steel sheet. Other metals and shapes as well. The steel sheet is available in one square foot and four square foot pieces. My second option is available at only one store. The store sells "Hobby Metals". The Hobby Metals are small pieces of steel, brass, and aluminum. These pieces come in various shapes and one of these shapes is sheet. Small pieces of sheet, like 4 x 4 inch. A good hobby shop will also carry the steel sheet you need. So take the tube off of the tractor, remove the patch, clean the area, and put on a new patch. And remember, getting this job done right will give you the experience and confidence to do this type of job again. You may need to do this in the future because you won't have another option and you will know how.
Eric

 

[2manyrocks]

Trying to move from an F to a passing grade.......

I hadn't re-pressurized the loader so the loader tube was still clean and easy to remove.

I removed the copper patch because it was going to cause galvanic corrosion and cleaned the tube with a wire brush in a rotary grinder. I cut another patch from a thin piece of sheet metal and formed it into a round shape.

I may have made another big mistake right there. The patch metal is about the thickness of todays' thin metal roofing and isn't the thickness of the loader tubing. Should I have used thicker metal for the patch?

Rebrazed it trying not to get it as hot this time. A real problem for me is I do not have a real brazing torch. I only have a mapp cylinder with a mapp torch like used for soldering copper pipe. The flame isn't concentrated.

This what it looks like now.

As a backup plan, I'm wondering whether to take it to the hose fabrication shop while I have it off the loader and while it's still clean. The fittings take a 7/8" wrench with an internal diameter of .672. The loader tube OD measures .520. The ID of the tube is .393. I don't measure well, but is this a standard fitting and hose size?

The overall shape of the tube is shown in the pictures below. I think I could get a hose made with a straight end and a 90 degree fitting on the other and it could be substituted for the metal tubing.

 

[etpm]

I don't know how big the hole is or how thin the steel is so can't say if your patch is too thin. But consider this: If the hole is 1/16" x 1/2" then it is .031 square inches in area. If your hydraulic pressure is 3000 PSI then the pressure pushing against the patch is 93 pounds. That pressure is concentrated in a small area but if the patch is strong enough even soft solder would be enough to hold the patch in place. And FYI, the reason your solder job looks so gloppy is because it never got hot enough for the solder to become fluid enough to flow properly. Your thinking that the flame isn't concentrated enough is right on. If you had the proper torch MAPP gas should work for the job you are doing. At least you are trying and that's good. In the end though you may not be able to get your torch to work and so will need to have a hose made up. You should be able to have a hose made up the way you describe.
Eric

 

[cbg8670]

I have brazed many steel to copper joints, and steel to steel 45% solder or higher is what we use. Havnt had problem with corrosion. Some of my joints will see 500 to 600 psi . Don't know about 2500psi
Steel gets hot quick if it glows you have to start all over. Clean steel with wire brush on drill works best(imo).

Another thought is get line off take to good weld shop have them patch with tig

 

[2manyrocks]

I don't see my brazing getting better without getting a better torch. I had to get the tube red in order to get the silver to flow and even then, I was getting globs.

I found another issue, an oil leak at the stub to the tractor brakes, that needs repair. While the tractor is out of service anyway, it might be best to take the tube to someone to patch while the tube is still clean.

 

[true temper]

Wish you were here I could easily fix it right up for you and show you how to do it.
Your redo photo isn’t perfect job but it just might work.
Don’t use a wire wheel to clean it before brazing it it just smears it and it won’t wet the silver good. Use sandpaper or emery cloth and clean it with oven cleaner before fluxing it.
Keep trying and you will get it, it will be a lot better than cobbling it up.

 

[2manyrocks]

Thanks for that. If it were a normal weld, I'd use a grinder to grind out the weld and start over, but with this being brazed, how would I redo this now? Grind it out, sand it, oven clean, flux, reheat, use thicker patch metal?

Is there an inexpensive brazing torch I could buy because trying to do this with Mapp cylinders isn't working that well for me?

 

[rScotty]

There are just about too many types of solder calling themselves "silver solder" these days. What you want is what jewelers use. It will often be called "silver brazing" rather than soldering because getting the silver braze to flow requires that the steel get to at least a dull cherry heat. Mapp or propane won't get hot enough to flow good high temperature silver braze wire onto steel. Well, maybe they will with a master, but for use mortals we use acetylene/air or acetylene/oxy.

At that point where the steel begins to glow, the silver braze will suddenly flow everywhere on the joint in a matter of seconds. Your task is just to hold the heat exactly at that temperature while it flows. Too much and it will burn the metal and ball up. Too little and it stops flowing. If you mess up, just clean and start over Cleanliness is everything. Flux is very important. Going slow is the right way. Nothing cleans a joint better than filing to good metal and then cleaning with acetone wipes. I never grind or sand. Too many particles.

People who do a lot of silver brazing I would often clean a joint, apply flux, and then cut some pieces of silver brazing wire and stick them into the flux about where you want them to flow. Let the whole thing dry. Now begin to apply heat - not to the joint but nearby and gradually move the heat into the joint. The flux will melt first into a protective liquid glass. Sometimes it will bubble and move the silver pieces away from where you want it, but just push it back using the tip of the remaining silver brazing wire.
Keep the heat on and the silver in position....the bubbling will stop shortly and that is when you know the silver is about ready to flow. Let it flow. Overheating will cause blackening, although it is common for the edges of the flux pool to turn black as it cools. Most of the flux will simply be glassy.

If you got a good copper patch on, I would expect that to hold. I've even seen some joints on bent tubing repaired by a method of making a flexible patch with copper wire wound around the tubing bend. Do the super cleaning followed by winding a coil of #14 clean copper wire onto the steel tubing for an inch or more and then silver brazing the whole copper coil turns together and to the steel tubing.

Always go slow when adding heat and use plenty of flux. You can add flux even as it heats up.

rScotty