Little question

[Andrey]

See picture, is this small white thing necessary or rather not? What is it for?

What happened: I am making a quite complex loop and 2 acryl pipes which I made today turned out to be leaking, so I will have to redo them once I buy more pipes. If only I knew how much work it will be - feels like having a second job.
So during the making of one of the leaking pipes this white thing got stuck and broke off when I tried to pull it out, so I just polished this end with fine sandpaper.
I don't want to buy another whole fitting, because both the metal parts and black ring are still okay.

 

[Vanzin]

HI,

the part is especially for PETG Tubes and is preventing PETG Tubes to disform, when the water temperature is gettig to warm. It is not really necessary but recommended to use, if you have PETG Hardtubes.

 

[Andrey]

HI,

the part is especially for PETG Tubes and is preventing PETG Tubes to disform, when the water temperature is gettig to warm. It is not really necessary but recommended to use, if you have PETG Hardtubes.

Hi, thanks a lot! I use acryl (PMMA) tubes, they are much harder to work with (may chip during sawing and require longer heating to bend), but the result is worth the hassle. The hardest part for me is to make them exactly as long as needed and stick them deep into both fittings, because acryl tubes are quite rigid.

Another little question: I can feel with my fingers that either the black O-rings or the tubes may have slightly different diameters, sometimes the ring is stretching when gliding along the tube, sometimes it's gliding easily without touching it. It's probably just 0.1 mm difference, but it's palpable.
The question is - is it too bad when the ring feels loose on the tube? Does it even matter after fully screwing the fitting? If it does, then can I use the duct tape to make the tube slightly thicker at the end?

 

[Andrey]

Good news: I remade the bad pipes, ran the dist.water test overnight and it didn't leak!
Now running a second test with coolant instead of water.
That means I can now answer my own question: it is not too bad when the ring is a bit loose, all that matters is that the pipe goes straight into the hole and the fitting is fully screwed.