Synthman - 14-3-2012 at 02:38
Hey everyone 
I am a uni student and am just looking at purchasing my first distillation setup. Obviously the American "standard" joint size is 24/40 as there are
plenty of kits this size on the internet. This is fine, and have been thinking about purchasing a kit of this size off ebay. But after looking at the
local Australian lab suppliers, the largest size they offer is 29/32 and that seems to be fairly standard here. Should I purchase an 24/40 kit from
online? Or would it be better to buy locally?
Or better yet, does it matter? And what actually is the Australian standard for ground glass joints?
Thanks!
Endimion17 - 14-3-2012 at 06:13
I don't know the Australian standard, but 24/40 is used in USA, and 24/29 pretty much throughout the world. 29/32 belongs to the latter standard, so
if that one is abundant, Australia might very well belong to the same group.
they do fit together (same 1:10 ratio), but their length differs, which can be a pain in the ass.
I wouldn't recommend buying different standards. Stick to one locally available. Even better - choose one taper and let it be the dominant taper in
your lab. Reasonable choices are 19/26, 24/29 and 29/32.
Dr.Bob - 14-3-2012 at 07:36
Be careful, the first number is the diameter of the opening, and the second is the length, but the taper should be the same for any with the same
FIRST number (diameter).
So 24/29 would fit into 24/40, and 24/40 might fit into 24/29, but stick in a bit.
But 24/29 and 29/42 will NOT work together, as an example.
I would recommend picking one size and sticking to it, either 14, 19, 24, or 29 mm diameter, at whatever length is readily available in your country.
Adapters are also readily available for most common sizes, like 14/20 to 24/40 or 19/22 to 24/40. But they add another joint to leak and piece to
break.