HELP: Fixing the Jar

[sissyfm]

Hi all,

I need your help and I also have a few questions.
I got myself a "jar" and now I want to seal it. At the bottom where the valve goes in, the hole is 20 mm wide.

What can I use to seal it properly (down 20mm hole) so I can connect a vacuum pump?

20mm hole down

At the top where the screw cap is, I’d like to cover it with rubber or something similar because otherwise it hurts the skin.

Screw cap

And two more questions:
3) Why do you actually add water when using the pump?
4) What vacuum level is good, and how long should you train your balls with it?

Thanks for your answers!

[krude]

I want to use a glass vase but difficult drilling a hole. I tried sucking air out. How are you going to make a vacuum?

Any suggestions would help