Quote Originally Posted by duraleigh
All those transitions mentioned above may not be available at HD/Lowe's....they carry the smaller sizes.

Plumbing supply or pool supply will probably be your best bet.
The pvc male tread coupler can be found at any pool store that sells plumbing parts.
The copper female thread coupler will probably have to go to a plumbing supply store. Note- they come in two varities.
1 is for use in DWV (drain/waste/vent). it has a short thread and slip solder end and is for use in systems that are not under pressure.
2nd type is for pressure supply lines and has a longer/deeper thread and slip solder end and is a bit heavier copper material.
The 2nd type is of course the better one to use but is harder to find. You can use the DWV type but i really don't recommend it, only use DWV if you have absolutely no other choice.

Be prepaired for "STICKER-SHOCK"! copper is expensive, dwv couplings can be $20-30 and presure couplings can cost $40-50 EACH!!!