Welding Tips and Tricks

I'm getting ready to fab some steel low-pressure hydraulic lines (2000 psi) and my experience with low-temp soldering (plumbing joints) vs. compression fittings makes me strongly biased toward joining the fittings with silver solder.

I'd like your advice on appropriate sil-sol rods and sources with reasonable prices. By appropriate rods, I mean ratio of silver, and appropriate mixes for steel tubing (about 0.070 wall"). Are sil-sol rods like SMAW rods, with some having very difficult 'personalities'? If so, I would need a rod that isn't prone to porosity, cold joints, or other demands that an unskilled novice wouldn't be able to handle.

And while superior, easy-to-use rods seem to be a bit higher in price (and I would prefer such rods) I'm hoping it isn't going to cost in the neighborhood of $25.00/rod!

Thanks for reading. All comments appreciated.

The more silver the easier they flow.
I just grab the 15% stuff the local HVAC supply store sells.
@ $8.00 a stick

15% can suffer leaching over time when used with steel. I would use 30% on carbon steel and of course with silver solder flux. But before attempting it I would be seriously questioning the suitability of this process against 2000psi. Is this going to be a capillary joint and what size? We need more info before a reliable opinion can be shared.

Coldman wrote:15% can suffer leaching over time when used with steel. I would use 30% on carbon steel and of course with silver solder flux. But before attempting it I would be seriously questioning the suitability of this process against 2000psi. Is this going to be a capillary joint and what size? We need more info before a reliable opinion can be shared.

Thanks! I like $8.00 rods as much as I like colonoscopies but $25.00-$30.00/rod for SSF-6 is insanity for someone at my skill level.

These lines are for a hydraulic system on a small tractor. The lines are 1/4" steel, and the fittings I want to use are the weldable type (steel). I hadn't seen them referred to as capillary, but indeed that is how the weldable joints are made, by capillary brazing.

As to withstanding the pressure, 2000psi is at the low end of this type of system -- the hydraulics in larger equipment can go several times higher. That's the reason I'm not just grabbing the cheapest sil-sol I can find. I haven't found specifications for solder in these joints; I hoped to find the knowledge/expertise here.

Thanks!

My 02c is study the technical specifications of the various wires and also avoid the cadmium free varieties. They are a PITA to use, like everything else that has been " greened ".....

At one time you could buy a a small roll of wire in a round clear plastic container that didn't break the bank.

kiwi2wheels wrote:My 02c is study the technical specifications of the various wires and also avoid the cadmium free varieties. They are a PITA to use, like everything else that has been " greened ".....

At one time you could buy a a small roll of wire in a round clear plastic container that didn't break the bank.

Thanks! Exactly the things I hoped to learn.

I've seen small rolls on fleaBay. I didn't really look, except to note the prices -- I assumed they would be too light on silver and couldn't serve. I'll have to check them when I get a handle on the nuances of the tech specs.

That $8 rod will probably do all the joints you are describing.

Have you considered bronzing as an option?

Trev

TRACKRANGER wrote:Have you considered bronzing as an option?

Trev

No, I didn't really consider it. I only have MAPP (and propane) and a POS BumzOMatic torch; I had the idea the torch doesn't lend itself to brazing. I hope to maximize the possibility of getting 100% successful joiints without having to invest in a quality torch and gas.

Should I be giving higher regard to bronze?

Thank you!

What is the depth of these joints?

If you have a good 1/2" of well-fit penetration for the joints, you "could" get by with plumber's solder for 2000 PSI on a 1/2" tube. The overall strength is proportional to the square of the wetted surface area (engineers correct me if I'm off on that...).

That said, I like silver solder. We use a rather expensive alloy at work, but I'd have to read the numbers tomorrow to give you reliable info.

Steve S

ShaunBlake wrote:

TRACKRANGER wrote:Have you considered bronzing as an option?

Trev

No, I didn't really consider it. I only have MAPP (and propane) and a POS BumzOMatic torch; I had the idea the torch doesn't lend itself to brazing. I hope to maximize the possibility of getting 100% successful joiints without having to invest in a quality torch and gas.

Should I be giving higher regard to bronze?

Thank you!

Sorry, I hadn't realized the heat source available. Stick with Silver Solder I reckon.

Otto Nobedder wrote:What is the depth of these joints?

If you have a good 1/2" of well-fit penetration for the joints, you "could" get by with plumber's solder for 2000 PSI on a 1/2" tube. The overall strength is proportional to the square of the wetted surface area (engineers correct me if I'm off on that...).

That said, I like silver solder. We use a rather expensive alloy at work, but I'd have to read the numbers tomorrow to give you reliable info.

Steve S

I don't have the fittings on hand yet; I think I said it was 1/4", but it will be 3/8". I expect they will not be 1/2" deep, but I think they must be at least 3/8", eh?

I would be pleasantly surprised if soft solder could be used. However, I intend to use sil-sol, but if the "lighter" (~15%) is adequate, I know that I can find a mix that I can handle without having to resort to the MuggyWeld horribly expensive stuff.

Steve, another big Thanks! Your comment about checking the numbers inspired me to do a little research. (I regret that I didn't do that instead of asking you folk to do it for me!) Soft solder's top strength would suffice, I suppose, but I don't know what must be done to get into that range. However, sil-sol at it's lowest would be adequate for my needs.

That's great!

Since I forgot to check the alloy today...

I do know that to get it to wet out properly, red brass must be heated to between brown and dull-red, so it's a high alloy, thus the cost.

Follow the math, follow the money...

Steve S