Originally Posted by ekjohns
thanks for the info. I will be doing this soon and I am not very good at soldering. If you have time could you give a nice description of how to solder the spud with tinning? I looked up tinning copper but that was on a flat sheet of copper with a special tool that was heated up in a furnace. Not quite sure how to do it on a spud
Start with this thread: http://www.homebrewtalk.com/f51/soldering-stainless-steel-155782/
Clean the entire back surface of the spud where it will be soldered. Use some coarse wet/dry sandpaper or a coarse Scotchbrite pad or similar. when the surface appears matt, wash it with some soapy water and then wipe with solvent.
When it's dry, brush on some flux and heat the spud with a propane torch by applying the flame around the inside of the threaded hole. Do not apply the flame to the flux. As it warms up and you see the begin to flux boil off, remove the torch and rub the solder on the spud. If it's hot enough, the solder will melt and begin to coat the surface of the spud, if not, re-apply the heat. The "heat, dab-dab" test process should only take a second or two. Once it's up to temp, it will only take a little heat to maintain the temp to finish coating the surface with solder.
Wash & clean the flux off the spud once it's tinned.
Thinking about it, you could probably set the spud on an electric stove burner and heat it up that way.
Clean the hole in the pot in a similar manner, flux around the opening of the hole & flux the spud. Be careful fluxing the pot, if the flux is allowed to dribble down the sides, it will discolor it a little if that matters to you. Set the fluxed spud on the opening and make sure the pot is blocked up level & so it won't roll.
Heat the spud from inside its threaded opening. Don't worry about heating the pot, try to avoid that. As the spud comes up to temperature, the solder you tinned it with will begin to melt and that will transfer heat to the pot. When you see the spud set down flush at the top & bottom, begin to apply solder to the sides to fill in the remaining gap. Watch your heat, the spud will be plenty hot which will give you enough working time without having to keep the flame on it constantly.
Don't go too crazy with the solder, strive for a meniscus around the edge. Too much and it will dribble and run down the side of the pot.
By not applying the flame directly to the pot, you avoid introducing heat distortion. On heavier pots or keggles that may not be a problem.