I have to pass a 6mm diameter metal tube through a hole in a plastic bottle (common PET coke bottle) and seal it very well. I have a bottle with a 6mm hole that I did with a Proxxon FBS 240/E and a Grinding bit and the metal tube is thigh passing through the tube.
My question is: What is the best way to seal this hole against water and oil? Relative pressure from inside to outside is expected to be something not really big.
The iron tube is not expected to move but it can happen often, so it will be good to have some mechanical resistance in this, if possible (only if possible).
Every suggestion is welcome :)