Sciencemadness Discussion Board

Using a 24/40 flask with my other 24/29 glassware

Mateo_swe - 17-7-2020 at 09:41

So i recieved my latest glassware order from ebay.
One flask, a dual neck 2000ml rbf has the wrong connections.
All my glassware is 24/29 and this flasks necks are 24/40.

Is this 24/40 flask still usable with my other glassware?
If i have understood this correctly both the 24/29 and the 24/40 has a 24mm diameter hole in the top and same taper degrees.
The only thing different is the length of the ground areas, 29mm for the European 24/29 and 40mm for the US 24/40.
So then my other 24/29 items should fit in this 24/40 flask, right?
Or are there other things that one must take into considerations here?

Syn the Sizer - 17-7-2020 at 10:05

Yep, as long as the first number matches you are good, 24/29 is 29mm long so just won't protrude in as far as the 24/40, and vice-versa, the 24/40 is 40mm long so will protrude a little further ~11mm into a 24/29 ground glass joint, but both are interchangeable. I had the same fear when I got a 24/29 EM flask and all my glassware was 24/40.

Edit:
Though 1 good point to make is if you get a male 24/40 joint and using it on a 24/29 female joint, be careful with grease, you don't want the bottom ~11mm greased to prevent contamination from your grease of choice in the reaction/collection flask.

[Edited on 17-7-2020 by Syn the Sizer]

[Edited on 17-7-2020 by Syn the Sizer]

Mateo_swe - 17-7-2020 at 12:04

Thanks.
I can use this 24/40 flask then.
Its a nice flask and its a hazzle returning it.

Syn the Sizer - 17-7-2020 at 12:51

For sure, it opens up to more glassware if the part in one joint size is sold out, you can check the other.

Syn the Sizer - 17-7-2020 at 13:51

I just had a thought, I think if a person was looking for a step down adapter to a smaller joint size and you own a mixture of 24/29 and 24/40 glassware, you might want to get a 24/40, depending on the clearance at the bottom of the adapter you might not have space for the extra ~11mm to protrude out the bottom on 24/29->19/22 adapter. I don't think it would be an issue stepping up to say 24/29->34/45

Fyndium - 17-7-2020 at 23:21

I feared at first I ordered wrong types of joints because I just a while ago ordered glassware that is mixed with 24/29 and 24/40 joints. Luckily they are interchangeable.

Most adapters look that they have a bulge to allow for headspace.

s-l500.jpg - 22kB

Syn the Sizer - 18-7-2020 at 04:28

Awesome, that is good to know. I thought after I made my first reply "I wonder what the clearance on an adapter was" so thought I should mention that, but now that I see the adapter, do remember seeing they usually have that bulge.

JJay - 18-7-2020 at 12:36

I personally prefer 24/29 flasks and 24/40 everything else. I have a combination of both sizes of both flasks and adapters. I have one straight-through 24/29 adapter with a gas takeoff that that won't accept 24/40 adapters with large drip tips, but in general, it's not a problem. 24/40 joints hold together more tightly. I think that attribute is desirable for most pieces of jointware and undesireable for flasks, but the practice of deliberately mixing 24/40 and 24/29 is not common.

[Edited on 19-7-2020 by JJay]

Syn the Sizer - 18-7-2020 at 12:48

JJay, That was my original concern with adapters. I had a feeling some 24/29 adapters night have just enough clearance for a 24/29 and the extra 11mm of a 24/40 would be too long.

I like your logic in concerns to the joint size of flasks and everything else. I agree, you want your parts to hold well and your flask to be more easily removed. if you need to switch it out or want to pipette a sample you don't want to fight just to get the flask off.

Sulaiman - 19-7-2020 at 11:30

not a massive concern but a 24/29 joint is 21.1mm minimum diameter,
a 24/40 joint is 20mm diameter,
not a huge difference but for cleaning, poking, stirrers, the extra 1.1 mm can make a difference,
just another minor reason to favour 24/29 for flasks, or vessels.

Syn the Sizer - 19-7-2020 at 11:47

Quote: Originally posted by Sulaiman  
not a massive concern but a 24/29 joint is 21.1mm minimum diameter,
a 24/40 joint is 20mm diameter,


That is interesting to here and a very good point. I guess the 24 really only applies to the maximum diameter, and as the 24/40 drops the extra 11mm it would still taper, 11mm makes a 1.1mm difference, would that be a 10% (9o) angle?

[Edited on 19-7-2020 by Syn the Sizer]

[Edited on 19-7-2020 by Syn the Sizer]