My son & I are building a Wyvern Engine from the Hemingway Kits, which has a split Phosphor Bronze bearing. The procedure calls for the the two halves to the be soldered together, machined, then split apart again. I purchased a Benzomatic MAP / PRO TS8000 Torch, which cane with flux and lead free solder, for the job. But all my attempts, on a piece of test brass, have failed. Is the flux and solder wrong? I was getting the parts red hot. Tried to indirectly heat the flux coated area on one attempt. The flux turns black and the solder balls up and does not stick!