A few weeks ago I mentioned the idea of soldering the end cap for the element guard onto the base of the elements itself. Here's a run-down of what I did for those looking for an effective and permanent solution :handgestures-thumbupleft:
Here's the pieces from Mac's custom element guard (minus the 32mm piece of pipe)
When sliding the 50mm end cap over the thread side of the base, I found that I lost too much on the thread and was not able to screw it into the socket in the boiler well enough...it would leak even done up as tight as I could get it, and there was a fair bit of wobble still in the element at this point.
Because the method shown in the previous photo, holds the 50mm cap against the socket...using it on the back of the element base would require it to be fixed permanently...and step in soft soldering an element :D