In a small bucket, make a holder that will assist holding the light bulb underwater for the drilling and filing process. This step is shown with a real light bulb as that was the original plan for this project, I will talk more about why this didn't work in step 8.

Drill a two inch hole in a scrap piece of wood that fits in the small bucket. Double this up and cut out one side to create the holder that will allow the light bulb to nest in the wood.

Attach another board on the back of the holder to index the location of the hole through the stem of the bulb.

Hold a piece of rubber (bicycle inner tube) to the bottom of the holder to seal the bottom of bucket when attaching it with screws.