How To Make A Homemade Vacuum Tube: Part 3 - The Plug
Channel: BlueJersey112
Date: 15/10/2012

And on to the 'plug', which acts as a support for the copper tube and the seal. As it prevents the tube from wobbling/bending excessively and breaking the seal.

The 'plug' was drilled with a hole saw. The diameter of the hole saw is dependent on the diameter of the bottle cap, as explained in the video.

The wood I used was 1 inch thick. When drilling, remember to stay away from any deformities, cracks, knots, rot, or anything that might ruin the structrue of the plug for your vacuum tube.