Get rid of the faucet was hard but with a long big clamp and some force, job done.
Important step! Fill the bottle completely with water before opening it! The water drives out the gaseous residues and thus avoids an unpleasant accident! I do not recommend this manipulation, at your own risk.
Removing the cap and rounding the edge.
Soldering and cutting
This was my really first soldering attempt... please don't judge ;) I have been training since.
Cutting hole for blowing air.
Messy task but it works well. Found an empty old extinguisher to make the template with some cardboard.
My old sander was used to vibrate plaster, it works not like expected but some air bubbles escape. Let it dry.