Demijohns come in a few shapes and sizes but the principle will be the same for all.
You will need a few tools to start with and be able to drill glass but this is only if the flex is to go into the Demijohn and out the bottom.
Drill and Glass bit
There are 2 options for the running of the flex. Out a hole in the side at the bottom or if you're not up to drill the glass then you can use a side entry cord grip.
Running the flex out of a side hole needs a 10mm hole drilled. Do some test drilling in bottle to find the best way. Have a look at Youtube for help on this but normally drill slowly whilst running water over the drill bit. Once you have done this if needed follow the next steps.
First thing is to measure the inside diameter of the opening. A tip is to get some thing cardboard and cut strips of until it fits inside. Then measure the width of the cardboard. This is the diameter of the bung you will need. Pick a bung from this section.
You will now need a lampholder. There are many to choose from so whilst below is a link to the lampholder section you can only use one with a 10mm fixing in the base. You can however have BC, ES, switched or un-switched and long as its 10mm.
A few other things to pick. Some flex cable and again there is a lot. You must use a 3 core flex for this project. Have a look here.
Now you will need a plug and maybe an in line switch which are here
Below are the last parts which depend on where you decided to run the flex.
Through the Demijohn and out the side these are needed.
Where the flex is not taken into the Demijohn
Please note other colours are available.
Please see our guides on wiring a lampholder and switch if needed.