Anyone here experienced in silver soldering?

[ulav8r]

1% silver bearing solder has a much lower melting point than Sil-Phos or true silver solders. 430 degrees vs. 1200 degrees or more. The flux included with silver bearing solder will burn at much higher temps and will create a "dirty" surface that solder will not stick to.

[elmacgyver0]

I would not call that "silver bearing lead free solder" silver solder. I believe that acid core stuff is made for plumbing and maybe stained glass windows, rosin core would be for electrical wires/electronics. silver solder is used for specialized stuff for the most part. HVAC, hydraulics, gun sights, carbide and tungsten joints, ect

The silver solder I'm familiar with is a solid wire that is not very flexible, more like music wire.
The "silver bearing solder" is something else, it does have a small percentage of silver.
I have used the hard silver solder to attach extensions on short gun barrels to bring them to legal 16+ inch length when building semi-auto versions of sub guns to conform with ATF regulations.

[elmacgyver0]

1% silver bearing solder has a much lower melting point than Sil-Phos or true silver solders. 430 degrees vs. 1200 degrees or more. The flux included with silver bearing solder will burn at much higher temps and will create a "dirty" surface that solder will not stick to.

This!

[country gent]

when I put together a cutter carbide on a steel shank I have freshly milled stoned surfaces. I then soak them in a 50 50 mix of white vinegar and hydrogen peroxide several hors or over night. this etches the surface to a nice surface. flux and lay silver solder in flux and assemble with a "third hand" holding them on the welding table. I normally use a #3 tip on the oxy acetylene torch When it hits temp I see the solder flow around the seam joint. the part then sits under the third hand until cooled down. Its then ready to soak and wire brush to remove the glass like flux grind and use.

[Hannibal]

when I put together a cutter carbide on a steel shank I have freshly milled stoned surfaces. I then soak them in a 50 50 mix of white vinegar and hydrogen peroxide several hors or over night. this etches the surface to a nice surface. flux and lay silver solder in flux and assemble with a "third hand" holding them on the welding table. I normally use a #3 tip on the oxy acetylene torch When it hits temp I see the solder flow around the seam joint. the part then sits under the third hand until cooled down. Its then ready to soak and wire brush to remove the glass like flux grind and use.

Thanks for the benefit of your experience. Good stuff!

[Hossfly]

Found that on line. Any particular solder you like? I think for starters I'm just going to try a new combination and avoid acid core this time. I presume things like acid core solder have a shelf life but right now that's just a guess.

Harris is what I’ve used.

[Hossfly]

You’re on the right track with what the guys are telling you about using the 45%-55% wire silver solder.
With the white flux, comes in plastic bottle and is a paste, it dont go bad, it will dry up but you just add a little water, comes with brush inside. Solder is sold 1 Troy oz. Plastic container rolled, not cheap. Joint has to be very clean, new wire brush clean flux and play torch appropriately to size of job. Oxy. Acct. works best with proper tip. Flux will turn amber color and start to flow then add small amt of your solder.
It is tricky but gets better with practice.

[Hannibal]

The flux included with silver bearing solder will burn at much higher temps and will create a "dirty" surface that solder will not stick to.

After sleeping on it and now that I realize what I have I suspect this is exactly what is happening.

[.429&H110]

I learned refrigeration in trade school.
You have a community college that might let you audit a class and see all the ways and ways of magic.

Taught me to bend and swedge copper, all sizes, rarely use a fitting. Fittings cost money, look bad.
Drop a silver ring in the fitting first, heat until the silver shows. Quick and minimum silver.
If you see a someone soldering refrigeration without a nitrogen purge your job is doomed.
Copper oxidizes on the inside to sandpaper grit, water plumbing washes it out
but in a sealed system you will have grit lubricating the compressor.
Compressors don't die, techs kill them.

It's a big subject.

[Hannibal]

I learned refrigeration in trade school.
You have a community college that might let you audit a class and see all the ways and ways of magic.

Taught me to bend and swedge copper, all sizes, rarely use a fitting. Fittings cost money, look bad.
Drop a silver ring in the fitting first, heat until the silver shows. Quick and minimum silver.
If you see a someone soldering refrigeration without a nitrogen purge your job is doomed.
Copper oxidizes on the inside to sandpaper grit, water plumbing washes it out
but in a sealed system you will have grit lubricating the compressor.
Compressors don't die, techs kill them.

It's a big subject.

I appreciate your advice. I'm actually attempting to solder mild steels together. Same basic principles apply however given the solder I had on hand I think my mistake was actually too much heat. Causing the flux to burn and creating a contamination problem.

I appreciate everyone's posts and advice. I've ordered a 45% silver alloy solder and a different flux. Hopefully this will work well with my project.

[Hannibal]

So to follow up, I re-cleaned the pieces and tried again using a much smaller tip and it worked perfectly. Apparently when I'd used it before I wasn't applying nearly as much heat so that was the problem.

I still want a stronger joint so I'll be doing more testing in the future once the 45% solder and flux arrives but at least now I understand what was causing me problems this time.

Thanks for all the replies. Lots of good information in this thread. I've learned a lot and I'm always amazed at the knowledge of this forum's members.

[.429&H110]

From a copper to copper point of view I really don't like phos copper.
Phos works fine, once, but it's a one shot one try then the phos is gone.
Phos is certainly not for repair work. Phos is cheap the Chinese love it.
And the Chinese are apt to have lead in their brass faucets.
1% Lead fills a brass mold better, cheaper, will make a water sample flunk a lead test.

Another subject that will kill you is Cadmium.
Long ago we used Cadmium solder, and Cadmium is still out there.
That is why we keep the wind at our back, face shield and eye protection.
Eye doctor told me you can get UV from a gas flame, when I got my cataracts out.
Now you tell me.

[.429&H110]

Long ago in NH story?
I tended an old 120hp Cleaver-Brooks boiler, brushed it, talked to it, set up it's variable firing rate 10-30gph. It's flue efficiency was amazing 90-95%, would almost condense flue gas, too bad that it made NOx, firetube, hydronic ran 230F flooded, heated offices, a gym and locker rooms, made enough domestic hot water to shower two hockey teams at once, looked like a locomotive and about as noisy.

It went into alarm one cold Saturday, the air pump had destroyed itself.
Primary air pump is a block of cast iron with a five inch cylinder bored through, five vanes spin offset pumping air, with motor oil oozing in. Two of the vanes broke and went round and round digging big chunks out of the cast iron, good thing the flame failure worked.

Dismounted the thing got on the phone was not a replacement anywhere best idea was to use compressed air?
Only 20psi, but a lot of CFM. Need a solenoid. Doable.
Old Guido was on campus doing trash wanted to know "Don't they teach you kids nothin in trade school?"

So Guido let me hold the rosebud, once the cast iron was 1000F? not quite glowing Guido started laying in silver solder. It was an ugly gobbery mess, but a cylinder hone polished it bright and round. I had it rehung before it was cool to touch, oil heat back on sooner than boss expected. Why the casting did not crack, I do not know. Heated slowly? Guido is long gone, and I miss the Guidos we have lost.