Fill the iron beer lid with water first, then put some borax, spray fire under the beer lid with a musket, and boil the borax water.

Soak the place to be welded in borax water.

Cut some silver solder and soak it in borax water.

Aim the fire of the musket at the place to be welded until it turns red, but don't overdo it, it will melt.

Put your flux where it is to be soldered and burn it together until it melts.

Because the flux has a low melting point, it melts first at the same temperature.

After the connection, soak it in dilute sulfuric acid until the teeth turn white, and take it out and brush it with copper wire. good