Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: Chemical Resistant Vacuum Tubing?
LuckyWinner
Hazard to Others
***




Posts: 146
Registered: 27-8-2018
Member Is Offline


[*] posted on 21-6-2021 at 07:15
Chemical Resistant Vacuum Tubing?


older threads recommend natural rubber tubing which is not greatly chemically resistant at all...

would thick walled viton tubing be suitable?
what mm outside inner diameter is needed to support almost absolute vacuums?
since its flexible I guess it will collapse if thin walled.

this will be used for solvent distillations...

there are silicone vacuum tubings but they also do not offer good solvent resistance
View user's profile View All Posts By User
Chemgineer
Harmless
*




Posts: 15
Registered: 25-5-2021
Member Is Offline


[*] posted on 21-6-2021 at 08:51


What about PTFE lined tubes?
View user's profile View All Posts By User
Herr Haber
International Hazard
*****




Posts: 905
Registered: 29-1-2016
Member Is Offline

Mood: No Mood

[*] posted on 21-6-2021 at 09:21


PTFE tubing is rigid.
I've never seen lined tubes.

I use Viton for my pump. Just look for something with an absurd inner / outer diameter ratio if you're pulling a really strong vacuum.




The spirit of adventure was upon me. Having nitric acid and copper, I had only to learn what the words 'act upon' meant. - Ira Remsen
View user's profile View All Posts By User
LuckyWinner
Hazard to Others
***




Posts: 146
Registered: 27-8-2018
Member Is Offline


[*] posted on 21-6-2021 at 11:05


what type of diameter, since my olives have a couple mm I cant go with 2mm inner diameter.

what outer to inner wall do you need for viton to not collapse?
View user's profile View All Posts By User
Fyndium
International Hazard
*****




Posts: 1015
Registered: 12-7-2020
Location: Not in USA
Member Is Offline


[*] posted on 21-6-2021 at 12:24


It's not too critical in my experience. I have used pneumatic hoses with 8mm ID and ~15mm OD and they never collapse or kink, and I always use 100% vacuum. For suction filtering I have used ordinary PVC/PU with normal wall thickness and even when they collapse a little sometimes, they work perfect always. PTFE tubing can be good if it is thick enough, but it is also very rigid, more like tube than hose, and it will kink instead of bend, unless the radius is huge. I have moved to using discardable tubing which is thick PVC or PU, I use it as long as it lasts and then replace it. Can't really beat 1€/m price tag.
View user's profile View All Posts By User
BromicAcid
International Hazard
*****




Posts: 3078
Registered: 13-7-2003
Location: Wisconsin
Member Is Offline

Mood: Legitimate

[*] posted on 21-6-2021 at 13:30


Usually just have a 50 ft roll of natural rubber tubing, when it gets brittle/discolored change it out. You need to change it out periodically from accumulated residues.



Shamelessly plugging my attempts at writing fiction: http://www.robvincent.org
View user's profile Visit user's homepage View All Posts By User
S.C. Wack
bibliomaster
*****




Posts: 2276
Registered: 7-5-2004
Location: Cornworld, Central USA
Member Is Offline

Mood: Enhanced

[*] posted on 21-6-2021 at 14:40


Glass. Perhaps the inside of other tube can be coated with something.

The best plan would be traps of perhaps several types in series.




"You're going to be all right, kid...Everything's under control." Yossarian, to Snowden
View user's profile Visit user's homepage View All Posts By User
ChemGlass
Harmless
*




Posts: 8
Registered: 9-7-2019
Member Is Offline


[*] posted on 21-6-2021 at 16:24


I have a roll of Aldrich Teflon tubing somewhere in storage. I don’t really need it. How many feet of tubing do you need? Are you opposed to having stiff tubing? I can’t imagine this Teflon tubing collapsing under high vacuum. It’s incredibly strong if I remember correctly from having last used it. I probably have around 10ft I think. I could spare some if you’d like to see if it works for what you need. Like if you wanted to pay just for shipping I could send you some Teflon tubing for free. I don’t mind getting rid of a few feet if you’d like to experiment with it.

[Edited on 22-6-2021 by ChemGlass]
View user's profile View All Posts By User
macckone
International Hazard
*****




Posts: 1784
Registered: 1-3-2013
Location: Over a mile high
Member Is Offline

Mood: Electrical

[*] posted on 22-6-2021 at 13:11


4mm OD x 2mm ID teflon tubing is widely available, look under 3D printer parts.
It is very flexible at that diameter. You would need something on either end if it is being connected to a vacuum pump and stand glassware.
If it is just for the area between the takeoff and the pump, just use automotive vacuum tubing.
It doesn't outgas, won't collapse and is resistant to a fair number of solvents, the ones that it won't work with are acetone or MEK. But it isn't sensitive to non-polar organics. I haven't tried it with amines, and it is not appropriate for nitric acid.
If you use it for nitric acid, you will need to replace it but it is not expensive.
View user's profile View All Posts By User
Sulaiman
International Hazard
*****




Posts: 3061
Registered: 8-2-2015
Location: UK ... on extended Holiday in Malaysia
Member Is Offline


[*] posted on 22-6-2021 at 15:07


2mm i.d. is rather small for a vacuum line, pumping down may be rather slow.

I would be more concerned with solvent vapours getting to my vacuum pump than interacting with the tubing.

I'd consider long pieces of glass tubing joined by short pieces of tubing.

My dual stage rotary pump does not collapse most thick-walled (2mm or more) tubing (pvc, silicone, rubber etc.)

pvc tubing contains plasticiser(s) that often interact with solvents,
rigid pvc (uPVC) pipe is more chemically resistant.




CAUTION : Hobby Chemist, not Professional or even Amateur
View user's profile View All Posts By User

  Go To Top