Step 1: The bits you'll need
The copper pipe I used was 15mm. So all the joints etc are to fit that size.
I give some links to places where they sell the bits you'll need. This is just to try to be clear about what parts i mean. I am not recommending that you use these suppliers.
1) About 1 metre of 15mm copper pipe (or tube if you're a plumber)
2) 90 degree soldered elbow joints - x6
3) Soldered equal tee joints - x5
4) Compression 90 degree elbow joints - x2
5) Compression stop end - x4
6) Endex female coupling, n2, 15mm.
In my picture this is already soldered to the bent pipe. The big end must be wide enough for
your bulb socket to fit inside.
7) A mains (e.g 240volt, in the UK) to 12 volt transformer. Mine came out of a broken desk lamp.
8) A 12volt dichroic spot light.
9) A socket for your bulb. Mine came from the same broken desk lamp as item 7.
10) 2 metres 0.75mm 2-core round flex.
11) About 1lb old lead piping. This is to melt and pour inside the base.
12) Isolating ball valve. Bottom left in the picture.
13) Ultra miniture toggle switch