Hi P
The heat source is an 11" 2Kw Copper Element with a 1.25" Boss like this...

..this is connected into the keg by welding a 1.25" stainless steel connector into the side wall of the keg. This is the type of connector I used...

The riser on my pot is 2" copper and the small plumbing shop I got mine from were happy to cut what I needed. The connection between the riser and keg is made using stainless steel ferrules like this...

The 2" stainless steel ferrules fit inside the copper pipe and must be silver soldered resulting in a fitting like this...

The same type of ferrule needs to be welded to the opening in the top of the keg and they are then connected with Tri-Clamps and EPDM gaskets like these...

The connection is very neat and completely stable, even with a high VM column & head

I recently made a new pot head with a ferrule fitted to the elbow and another to the top of the riser. This makes cleaning and storage much easier.

I also installed a dial thermometer in the keg so I'd know when to turn on the water to the condenser...

...the insulation material is called Armaflex and it's brilliant stuff if you can get it.
Here's a pic of my keg in the nude so you can see where I put the different parts...

If you need anything else just give me a shout.
AM
