That is less than 1% silver. https://db1736767dbd5e7094bb-d61bbc5...c56171125c.pdf
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That is less than 1% silver. https://db1736767dbd5e7094bb-d61bbc5...c56171125c.pdf
there are eutectic, or there used to be, solders available for joining steel and stainless steel. I still have a couple large spools of the stuff that will join stainless. it works great for putting stuff like commercial kitchen hoods and such together but not as strong a joint as mig, big or stick.
It's either joint contamination or not enough flux.
My guess is it's a flux issue.
But I did wonder if your scotch-brite pad was contaminated with oil or something which in turn would contaminate your joint.
New pad and I cleaned it with acetone before applying heat so I can't fathom how. I agree it sure acts like it though.
being 1/4" mild steel and pins for alignment I think I would opt for a tig weld with pre heat of the material. A good brazed joint will work. silver solder would be way down on my list do to the amount of solder and cost.
A lot of our silver soldering on bigger tools we would pre heat on a piece of carbon or aluminum in the furnace clamped together to temp then pull them out and touch the solder to them. You got a beautiful joint good penetration/flow and little warpage.
On medium to big parts a plain propane or map gas torch is going to be wanting getting up to temps required.
1/4" can easily be veed out and welded With the right filler rod when cleaned up the weld will disappear. A good tig weld will have almost no splatter and the pattern or grain will polish out quickly.
I normally braze cast iron in bigger jobs, steels aluminums stainless tig or mig. I reserve silver solder for little jobs or attaching carbide cutters to shanks. soft solder is for electricals and plumbing.
Regardless of silver braze you are using you want .002" to .005" clearance for maximum strength and wicking. For larger areas like you have light prick punch marks work well or silver braze foil/sheet. Never used this one but this is an example of the product. You would cut a 7/8" x 1 7/8" piece and sandwich it in between the pieces with flux.
https://www.amazon.com/Silver-Brazin...07S67TWKP?th=1
https://www.canadametal.com/wp-conte...lver-alloy.pdf
How about 2 or 3 flat head screws 1/4 20 drilled thru one and tapped into the other. with the pins that will be as strong or stronger than the solder joint. Easier too.
clamp on the pins lay out the holes center punch drill a #7 hole separate open one side to letter f or g countersink and bolt together.
Will be awaiting your PM
Soldering can be a bit of an art form.
I used some of that soft silver bearing solder to solder two stainless steel mixing bowls together to form a large spherical still.
I tried using a torch and the solder just balled up like you described.
I finally got it to work using a heavy antique coper soldering iron, who would have thought?
I did use a liquid flux and heated the iron with a torch, it does not take that much heat for the soft silver solder, it does take finesse.
You have to use the iron to smear the solder on the part kind of like frosting a cake, once you get both parts wetted with solder you can put them together and heat them to get them to join.
Of course, this won't work with the hard silver solder, that takes a lot of heat, like brass brazing.
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
I should be opened up now. Did you receive my PM a little while ago?
Ill see if I can find it and resend it.