Soldering SS

[SUGARSMITH]

Any advice on soldering a ss 3/4" npt coupling to the side of my evaporator pan. The one that was on there broke off and I need to solder it back on. I know to clean the area really well and clean it with flux/acid, I plan on using silver solder and a mapp gas torch. Is there anything I am missing other than a lot of luck ?

[Southtowns27]

You need to use an iron to solder the SS. The torch will get the stainless sheet too hot and the solder will just bead up and run off...been there, done that. However, it will probably be helpful to preheat the heavier fitting with the torch, that way the iron won't overheat the sheet while you're waiting for the fitting to get hot enough.

[tylerj]

If you use a torch use the smallest flame you can manage. Too much and the ss will oxidize and nothing will stick. I used a liquid ss flux by Lennox and it worked quite well with the lowest flame I could sustain on a propane torch. I would pre-tin both the hole and the fitting separately then re-clean both.. apply more flux and join together. I would apply the solder to the ss with it laying flat (evap on its side if possible). It may be tricky to try to apply it on a vertical surface. Here is a picture of a sink I soldered some copper tubes too. One did leak under heat so I had to re-solder it.

[sniperdodo]

I found a really good video on youtube that shows an excellent way to dimple and solder.
http://www.youtube.com/watch?v=OpMFQFi6Hh4
if the link doesnt work go to youtube and search "Dimpling and soldering a 1/2" NPT coupler in a stainless homebrew kettle / pot "

[mtcrumpit]

there is a guy in New Boston NH that fixes pans. not sure how far that is from you.

[abbott]

My float box had a tab soldered to it to bolt it to the pan with that broke off. I used a torch to melt the old solder away, cleaned everything with flux, sanded, and cleaned again. I tried to solder that stupid thing a half dozen times or so, but in the end, here's what worked: I made sure everything was really clean and sanded well. I heated the tab (separate from the float box), added a little more flux, and kept heating until solder would melt onto the tab. I tinned the area that would be touching the float box, then set the tab aside to cool. Next i did the same to the float box. With them both tinned, i held them together and heated the tab until the solder melted together. To my amazement, it stuck! My first soldering success! Clearly i'm no professional, but maybe this will help you get the job done.

[Flat47]

Not too sure about stainless nipples to stainless pans, but I've soldered lots of brass fittings on to pans with a handheld mapp gas torch. I keep the flame only on the nipple. Like others have said, the thin stainless will over heat.

[SeanD]

I put one on a steam table pan using a torch. I had all the trouble mentioned here. What worked was after the cleaning and flux, I heated the area by waving the flame across the area like a pendulum ten times so that each swing up and back counted as one. Each count was about one second so the metal was reading for tinning in about ten seconds.

Sean

[maple flats]

I put a female adapter on my condensate pan by wire brushing (ss brush), fluxing (special SS flux), then wraping a piece of silver solder around the adapter where it was to be soldered. Then I held the fitting snog and heated the adapter with a torch. As soon as the solder melted I took the heat off. Perfect looking and it stood the torque test with a pair of pliers. The silver solder I have is only 1/16" wire.