You're beating a dead horse, hardware stores don't carry such items unless they also sell scientific supplies
Obviously, you didn't use the terms "water" and "aspirator" together when you searched the Hive, or you would have found
Post 292979
(wolfx: "Try again with an aspirator, buy a GOOD one ( for ...", Methods Discourse) Post 220694 (missing)
(chem_123: "Re: Water aspirator question", Newbee Forum) Post 213705 (missing)
(spric: "Re: Asspirators!", Newbee Forum) Post 194849 (missing)
(wolfx: "Re: vacuum question", Newbee Forum) Post 50137 (missing)
(BrightStar: "Re: another aspirator question", Newbee Forum) Post 31473 (missing)
(blue_diamond: "Success!!!", Methods Discourse) Post 16254 (missing)
(savestheday: "Re: Some aspirator questions....", Chemicals & Equipment) Post 16242 (missing)
(Felix: "Some aspirator questions....", Chemicals & Equipment) &
Post 163841 (missing)
(randolph carter: "Who has the best aspirator?", Chemicals & Equipment)which would have made your quest much easier
