In reply to message posted by Bruce T:
I have been having trouble getting a good seal on some 2″ brass ball valves that I am connecting to some existing irrigation futures.
the 2″ type “L” copper futures have male adapters silver soldered on the ends.
I think that they have been overheated from the oxy acetalyne and annealed because no matter how much teflon tape or paste I use on them, the male adapters bury themselves with little effort.
I am thinking that the adapters were annealed making the threads so soft that they loose their pitch as soon as they are fitted into the valves.
I had no problems with the male adapters above ground that were soft soldered.
Or do I have to take out some slab and replace the MIP’s?
Very common problem when folks use Oxyacetylene and do not know to use the flux properly as a guide line.
What you can try is use Quick wick with leak block to fill the little imperfections and this should stop the leaks.
If worse comes to worse you can cut out the existing C M adapter and use a C C good quality ball valve with Hercules 95 -5 solder flux combination as this should over come the over heating the other un knowning handyman did.
Many of the non skiled have no clue to brazing and watching the flux as a temperature guide line.
If you have the need to braze lines hire a “plumber” who certified to braze medical gas lines under the guide lines of the AWS and NFPA.
Even though this is slightly over kill I would rather have a more qualified mechanic then a border line handyman.
By the way as a certified medical gas welder/brazer I know there are some lower temperature alloys out there that you might be able to use if brazing with in FDA requirements and a tensile joint strenth of over 87,000 PSI.
Feel free to E mail me for other possible options