[Arran]

I have already figured out how to make a replica condenser can out of copper pipe, the trick is that copper plumbing parts come in standard dimensions and and the Mershon condensers fall somewhere between those standards. Pipe usually goes by inner diameter and the caps, couplings, and nipples are made to match the outer diameter. So the Mershon can may end up being 1-3/16 inner diameter and the standard pipe may be 1-1/8 or 1-1/4 inner diameter. The thickness of the wall of a water pipe is also thicker then a Mershon since it has to bear a certain pressure, so the pipe caps are thicker walled as well, if you look closley at the cap on a Mershon it also has a series of small holes around the perimeter. For the bottom you can use a copper or bronze threaded nipple and then fit an insulator inside of it. So the bottom line is that you can make an acceptable substitute for a Mershon can but not an exact replica out of plumbing parts.
Regards
Arran