Bought two round bottom bottles today with embossing on the base

[ROBBYBOBBY64]

Just round-bottom sodas, not hamiltons. Hamiltons have a football shaped body, as in the image provided by RobbyBobby64.

William S. Hamilton patented the torpedo bottle in 1809. I see lots of people refer to any bottle that has a rounded bottom as a hamilton. Good information, thanks for correcting this error.
ROBBYBOBBY64.

 

[ROBBYBOBBY64]

Flux is good. A good wire brush to remove oxidation first is also needed. I used to repair electronics and and coils on heat pumps. I never used silver solder on circuit boards as the high melting point would damage the components. Silver was great on the copper coils, but required us to use MAP GAS to get it hot enough to melt properly. A majority of the time tin/lead solder is sufficient for most applications.

I remember how to use a solder sucker. I have a computer electronics degree.
Love messing with things, improving or at least super sizing.
ROBBYBOBBY64.