Silver soldering BS blades or Carbide?

[f350ca]

Steve, your POC brand welder looks like it should have worked, but sounds like they forgot the annealing step. The few welders I've used welded the blade then you slid the clamps away from the weld if I remember, then passed a lower current through the blade to bring it to annealing temp.
The battery should give plenty of welding current.