Connect copper to polyvinyl chloride pipe by attaching pipe thread adapters to the two pipes and screwing the fittings together. Use solder and flux to attach the male pipe thread adapter to the copper pipe and PVC primer and glue to attach the PVC female adapter.
To prepare the copper for the joint, cut the pipe to length and dry fit the pieces. Make sure the cuts are as smooth as possible for leak-free joints. Use emery cloth to clean the copper pipe at least 2 inches from its end. Clean the inside of the adapter with emery cloth.
Use a brush to apply the flux to the outside of the copper pipe and the inside of the fitting. Coat both surfaces evenly to ensure a good connection, slide the adapter over the pipe, and twist to distribute the flux evenly. Heat the joint with a propane torch until it is hot enough to melt the solder. Touch the solder to the pipe so that it melts and collects in the joint.
Cut the PVC pipe to length and trim any burrs from the end. Apply the purple PVC primer to the pipe and adapter. Once it dries, apply the PVC glue to both pieces, and slide the adapter onto the pipe as far as it can go. Once the copper adapter is cool, apply Teflon tape, and screw the joint together.