This has got to be the best way to connect airline tubing to DIY yeast CO2 generators.
Aquarium silicon does not properly stick to the plastics used in soda pop caps, so a bulkhead fitting is needed. They can be purchased, but are hard to find and therefore expensive.
A BIC pencil is the only material needed. They are very common, so look around your house for a couple.
The outline of steps are here:
1.Find a BIC pencil. Color does not matter.
2. Snap off the clip
3. Use pliers to gently pull the plastic tip off.
4. Hold down the lead-dispense button at the end.
5. Cut here(line is thin, look carefully):
6. Take your tip and cut here(thin line):
7. Attach the two back together
8. Slip through your cork or cap for CO2 generator.
9. Easy mixture changes, no leaks at all.
Done! Brilliant idea, yes?