O-ring groove too deep - options

Question

O-ring groove too deep - options

Tmoose (Mechanical)

(OP)

20 Dec 16 13:30

We may have a situation where an o-ring groove is so deep the o-ring will not be squeezed at all at installation.0.25" Ø section. Low pressure oil seal.

I think I've seen instances where a second, very small section o-ring was installed first to provide a seal.
I was surprised when I found nothing in all my o-ring information.

Does anyone know of an "official" fix?

monkeydog (Aerospace) · Answer 1 · 2016-12-20 14:12:11

Have you looked at going with a fatter o-ring?
You may have to open the with of your o-ring groove.

dgallup (Automotive) · Answer 2 · 2017-01-05 15:03:10

I would not trust 2 o-rings, seems entirely hit or miss. Sounds like a one off problem so a custom shape seal is probably out of the picture. I would go with either reworking the part if possible or a bigger o-ring cross section which may require cutting a wider groove as monkeydog noted.

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1gibson (Mechanical) · Answer 3 · 2017-01-05 17:03:33

Can you get a weird profile (X section) O-ring of a larger size into the existing groove? Far from official but it might work.

Or maybe try to cut a thin garlock or similar gasket to drop into the groove and take up some space? Like a backing ring?

wtxhorsman (Mechanical) · Answer 4 · 2017-01-11 21:57:24

You may contact Parker O-Rings. I can't think of the name of the seal to save my life right now, but a few years back we used them in tools that had worn O-ring grooves and they solved our issues on tools pressure up to 30ksi. Worst case you can do like our technicians did and wrap the grove about 30 times with plumbers tape....

Tmoose (Mechanical) · Answer 5 · 2017-01-21 01:43:09

The part was assembled and pressure tested OK.
The assembly specialist said the o-ring looked barely flush in the groove, and the cover assembled "too easy", kind of confirming the measurement was correct.

Thanks for the suggestions.

Compositepro (Chemical) · Answer 6 · 2017-01-21 04:03:26

You may find that on a cold day that o-ring does not seal at all. Try putting your assembly in a freezer and then test it again.

monkeydog (Aerospace) · Answer 7 · 2017-01-21 16:21:42

So, after the suggestions provided on this site, what approach did you use?

Tmoose (Mechanical) · Answer 8 · 2017-01-21 17:23:53

For various reasons the component was used with the 0-ring groove depth neither confirmed, nor corrected.
The part was assembled and pressure tested fine.
The assembly specialist said the o-ring looked barely flush in the groove, and the cover assembled "too easy", in my mind confirming the "too shallow" measurement was likely correct.

That particular O-ring is not likely to get very cold, very often.
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O-ring groove too deep - options