Soldering or welding stainless steel objects together
The major trick with soldering stainless steel is using the correct type of flux, which needs to be very aggressive to remove the oxide layer which is what makes stainless steel "stainless."

You will require a flux specifically made for that, and then you will need to carefully clean the flux residue off when you are done soldering. This can be done with ordinary low temperature solders, no particular need to pull out the oxy-acetylene torch. It may also help to wire-brush with the flux in place, so that the brush mechanically abrades the oxide layer and the flux coating keeps it from re-oxidizing.

If that proves to be too weak, silver brazing (commonly misnomered as silver soldering, which is even more confusing in the era of silver-bearing low-temperature lead-free solders) or "normal" bronze brazing is considerably stronger. Bronze will have a color mis-match, which matters to some folks.

95-5 Tin-Antimony is a low-temperature solder that might be a touch stronger than some others, and which works well on stainless IMPE.