In some applications, copper pipe can be TIG or MIG welded to copper pipe or to fittings. One example might be in antenna construction, but this is not what we usually encounter. Normally we braze or...
Modern seamless pipe is extruded. The process starts wit a large cylindrical ingot like a big fat copper washer being forced through a a smaller diameter die to create a smaller diameter but longer...
tig or mig depending on the wall thickness Copper to copper is either soft soldered, or silver solderedSilver solder is a bad term as "solder" normally means lead content according to the AWS
You should not connect a lead pipe to any pipe. Lead is not legal to be used for any pipe anymore. If performing a repair on a waste line lead and copper can be joined by a rubber coupling with steel...