I've only just discovered TPU!

[Radian]

I wanted a particular sized O-ring and was about to buy a selection kit when it struck me that a flexible 3D printing filament would allow me to print one instead. After a quick search, Thermoplastic Polyurethane turns out to be a thing!

 

 

 

I'm besides myself with joy!

[dpmiller]

what's the temperature and chemical ratings of the printed item?

[SteamyTea]

9 minutes ago, dpmiller said:

what's the temperature and chemical ratings of the printed item?

Ask NASA, they know how to cover up a substandard O Ring.

 

[Bonner]

TPU is a great material and useful to be able to 3D print with it!

Just a tip for anyone who does have the kit however.... You can buy O ring cord which can be cut to length and joined with superglue. The only trick is cutting the ends square and getting a smooth joint but you can make a jig to help with that.

We use O rings made like this at work for testing pipes, up to about 2000psi (above that the material starts to extrude so you need a metal composite seal)

[Radian]

9 hours ago, dpmiller said:

what's the temperature and chemical ratings of the printed item?

 

Unlike PLA and ABS filaments the glass transition point is below zero i.e. it's flexible at room temperature and above. The typical printing temperature is around 200^oC so I would guess it's OK up to 100^oC. UV stability is supposed to be better than PLA etc. and chemical resistance should be fairly good as you'd expect from PUR. It should be good with petrol but not engine oil.

 

10 hours ago, SteamyTea said:

Ask NASA, they know how to cover up a substandard O Ring.

 

Feynman wrote at length about his experience in "What Do You Care What Other People Think?" which, like all his books, is a must-read.

 

9 hours ago, Bonner said:

You can buy O ring cord which can be cut to length and joined with superglue

 

Yes, I've done that before and was planning to do it again when it struck me that I might be able to print something the exact size. Superglue on even tiny little drive-belts like those in CD drives is incredibly effective - but you're right about needing a jig to line up the ends.

 

The bit that got me really excited was the prospect of making custom gaskets of arbitrary 3D printed shapes from TPU. Then I realised both parts of an electrical  box in the case of the thing I'm making could be made semi-flexible and hence watertight when secured together.