aonomus - 9-11-2009 at 14:41
So for $2 a piece, I bought 2 gas washing bottle bottoms. They have a 29/42 standard inner taper (rough surface out), and are 125mL.
Now what I'm wondering is how can I make something to turn these into useful devices again. Two thoughts I had were:
1. Simple rubber stopper + 2 tubes (1 gas inlet with a polyethylene airstone, 1 outlet). Not the greatest seal, and under any real pressure it might
pop off. Fortunately the bottles have little glass hooks out to the sides, so I could use springs, strings, etc to secure the stoppers so even under a
fair bit of pressure they wouldn't budge.
2. Suggestion from a friend, machine out a HDPE cylinder so that it has the 29/42 taper, and find a way to seal glass tubes to HDPE.
Does anyone have thoughts on either of these methods, or recommendations?
Edit: turns out its 29/42, not that it matters 
[Edited on 9-11-2009 by aonomus]
Arrhenius - 11-11-2009 at 17:24
Both sound like fine ideas. Polyethylene would last longer. Just put teflon tape to seal it, and drill holes so that the tubing fits snug. Generally
you don't use these bottles under pressure.