Sciencemadness Discussion Board

Tubing I.D. and Material for 10mm Connectors

artemov - 31-8-2019 at 22:40

For glassware such as these below (barbed connectors are stated as 10mm), what inner diameter of the tubing should I get (6, 7, 8mm)?

If the material are less elastic than rubber, for example silicone, vinyl or Viton, should I get a slightly bigger size?

What material is good for halogens and acids (nitric acid), and vacuum too, value for money wise, as I prolly won't deal with those often?

Cheers.






monolithic - 1-9-2019 at 04:25

I use 5/16" (7.9 mm) silicone vacuum hose on "10 mm" hose barbs and it works perfectly. You want to undersize it by 1-2 mm to get a tight fit, assuming your hose material is reasonably flexible. My silicone tubing has held up to organic solvents (xylene, toluene, ethyl acetate, hexanes, etc.) and some acid fumes (acetic acid mostly) without issue. I doubt it would hold up very well to nitric acid fumes, however.

[Edited on 9-1-2019 by monolithic]

wg48temp9 - 1-9-2019 at 05:15

Quote: Originally posted by monolithic  
I use 5/16" (7.9 mm) silicone vacuum hose on "10 mm" hose barbs and it works perfectly. You want to undersize it by 1-2 mm to get a tight fit, assuming your hose material is reasonably flexible. My silicone tubing has held up to organic solvents (xylene, toluene, ethyl acetate, hexanes, etc.) and some acid fumes (acetic acid mostly) without issue. I doubt it would hold up very well to nitric acid fumes, however.

[Edited on 9-1-2019 by monolithic]


Silicone rubber is not considered compatible with Xylene, toluene, and hexane. I used it once as fuel line on a chain saw it became very soft but cracked at the barbs. Of cause its dependent on time and temperature and the type rubber. Some fuel hoses do have a silicone rubber covering but with a more compatible inner sleeve.
https://mykin.com/rubber-chemical-resistance-chart-3

draculic acid69 - 1-9-2019 at 07:36

I've always used clear aquarium tubing for everything and it's been fine but now I'm using that shitty brown rubber tubing for condensers as it's not so stiff which in condenser lines is a good thing.wouldnt use it for anything other than that though.

monolithic - 1-9-2019 at 07:57

Quote: Originally posted by wg48temp9  
Quote: Originally posted by monolithic  
I use 5/16" (7.9 mm) silicone vacuum hose on "10 mm" hose barbs and it works perfectly. You want to undersize it by 1-2 mm to get a tight fit, assuming your hose material is reasonably flexible. My silicone tubing has held up to organic solvents (xylene, toluene, ethyl acetate, hexanes, etc.) and some acid fumes (acetic acid mostly) without issue. I doubt it would hold up very well to nitric acid fumes, however.

[Edited on 9-1-2019 by monolithic]


Silicone rubber is not considered compatible with Xylene, toluene, and hexane. I used it once as fuel line on a chain saw it became very soft but cracked at the barbs. Of cause its dependent on time and temperature and the type rubber. Some fuel hoses do have a silicone rubber covering but with a more compatible inner sleeve.
https://mykin.com/rubber-chemical-resistance-chart-3


Yes, it is incompatible with direct exposure but after a few hundred distillations it's still holding up. I chose silicone because it was cheap and easy to find. There are better options, perhaps at a higher cost.

It's also important to consider wall diameter. My tubing was something like 2.5 or 3.0 mm wall diameter, which lets me pull a good vacuum without the tube collapsing.

[Edited on 9-1-2019 by monolithic]

Herr Haber - 2-9-2019 at 04:04

8-10 mm depending on the material and it's thickness.
I used some silicone for NoX and it showed signs of aging very fast. Plain rubber on my vacuum pump didnt look good either after a few distillations.

I now use Viton for almost everything. As a general rule its easier to bend than Teflon but has the same chemical resistance.

artemov - 2-9-2019 at 04:37

Thanks guys. 8mm silicone/viton it will be :)