Lead contamination is extremely unlikely. Silver solder does not, as a rule, contain lead.

My guess is that the little pallion of solder sitting there causes the flux to pool up there which, when the solder melts, changes the surface tension of the area, resulting in a small declivity. I would guess that if you did a cross section of it under high magnification you would see the it actually looked like an impact crater - that is, lower in the center and the edges actually slightly higher than the surrounding metal. The metal that is "missing" from the center of the crater has to go somewhere, it doesn't just vanish into thin air.

That's my guess, I'll be interested t hear what others have to offer.

Rich

Interesting theory. I typically set my solder pallion in the wet flux, then warm it until the liquid cooks off. Is that recommended, or do most folks cook off the liquid first and then add the solder? The latter seems like it would eliminate a flux pooling problem, if that's what's going on.

Here's a theory, if I had to really come up with one: Maybe when the solder flows, it has capacity to draw in some silver from where it is making direct contact, which then all flows into the seam via capillary action, thus "sucking" some of the base metal away from that particular spot. That could explain the missing metal. It seems like I have this problem more with Easy Solder than with Medium or hard, but I haven't really been keeping careful count.

If this theory is true, I have to assume you are using too much heat. John Christiansen

You're doing it the "approved" way. If you dry the flux first and then place the solder there is no flux on the solder itself and it develops oxides before it melts. That "uses up " some of the flux reducing those oxides, leaving the flux less aggressive in combating oxides in the joint itself.

I gave up using pre-cut solder pallions for anything other than tiny little inaccessible joints years ago. I use wire solder and get the joint hot and the bring the solder into the flame and feed the joint just enough to fill it. It takes a bit of practice, but you can get the practice using soft solder and copper until you develop the feel for the process. After you do, you'll never look back.

Rich

Ahh. I have noticed that when using the pick to solder, if I heat the little solder piece too slowly (on the charcoal block), it turns into an oxidized, crumbly, useless little crumb. If I attack it quickly, it turns into a proper little droplet of molten metal.

I had not really considered the oxidation of the solder itself before - only worrying about the sheet/wire I was fabricating.

That doesn't really address the pitting, but I think I'll start fluxing my solder when using the pick technique - duh. Seems obvious.

I do have wire solder, and usually cut a nib off the end. I'll try just probing it in there when all is good and hot. Either way, the problem seems related to everything being too hot for too long. I think the quicker the whole transaction takes place, the cleaner the result. Having those little solder chips frying on there for 30-60 seconds is too much. Adding the solder at the last second- right when it's hot enough to flow - whether by pick or wire-end - seems to be the way to do it. No prolonged frying, less oxidation, no pits. We'll see how this goes.

Talking to myself again....

Last night, while I was waiting for some wax to burnout, I did a bit of silver soldering using the end-of-the-solder-wire technique. It worked beautifully! You can apply as little or as much as you need, easily adjusting to how the joint receives the solder. No pits, no huge fillets, no gaps, no waste. Very nice. Thanks for the tip - and as a bonus, I have a nice little pendant to show for my efforts.