copper vs pvc compressor lines?

Having worked in the heating / cooling (HVAC / R) field, I'm used to black pipe, but I also would not be the least afraid of brazed copper. "Silfos" is easy to use with an oxy/ acet torch and requires no flux.

Biggest problem is COST Many welding stores won't sell "by the stick" IE they won't open a box. You might "friendly up" to a local refrigeration outfit.