what to use to seal glass tube nozel hole

hey i have a glass tube extractor, using butane. what can i use to make it seal better? im using power 5 with the blue nozzle caps. but it doesn't seal perfect.

Grab some Teflon Tape aka plumbers tape....

Wrap around butane nozzle...seals perfectly.

thanks. i just really dont want the butane to react with the teflon and put contaminents in my oil.