I have a soldered copper water pipes that terminate in a 3/4" male thread adapter. That is screwed into a brass gate valve female-female. The valve won't close fully.
I want to cap the pipe. I can use a pipe plug on the brass valve or remove the valve and use a pipe cap on the copper thread adapter. I don't want to un-solder the thread adapter for a sweat cap.
Shopping around, I find plugs and caps in PVC, galvanized iron or black iron. Copper threaded caps seem nonexistent and brass ones are rare and expensive.
I don't want to use solder because it involves soldering.
I don't want to use brass or copper because the stuff is expensive. Can I get away with PVC? This is all on cold pipe. What's my best choice to avoid galvanic corrosion problems?