Experience with PTFE tubing & glass connectors?

Question

I'm wondering which PTFE tubing size to get to connect to normal 10mm OD glass connectors. For a silicon hose I would take an ID of 8-9mm as it is flexible but I think PTFE is quite rigid.

Anyone has some experience with PTFE tubing?

Answer 1

In short: Do not attempt a direct connection of the PFTE hose with the glass.

Instead (assuming the tubing shall transfer gases with little pressure only):

• Because to the (compared to silicon) lesser flexibility of the tubings made from PFTE, you should consider to use glassware with threaded joints with detachable connectors. This a theme already seen with condensers, e.g.

  

  (source)

  but may be equally applied to impingers

  

  (from here)

  or overhead exhausts:

  

  (from here)

  These connectors may be replaced with ones made mostly out of PFTE, too, e.g.

  

  (source)

  Thus you may connect the tubing to the connector at the bench (gentle warming of the tubing with a heat gun may help), secure this end with the clip, and then mount the connected hose to the reactor. It is faster and more secure (should you need a bit of force, damages are to the tubing and the connector, but not to the reactor) than the direct mount of the tubing to the glass.

• The other side of the PFTE tubing will connect with the metal ferrules to your gas supply, e.g.

  

  (screen photo at 1:04 min from this video)

  Depending on the dimensions, the fittings by Swagelok are sold in sets of 10; a typical mechanical workshop of your university may have them already in the shelf. The less pricey Bowden connections used for 3D printers (e.g., here) are designed for compressed air.

As for any equipment working with gas: monitor the gas pressure in your reactor and use a safety release / pressure valve.