Has anyone upgraded their O rings yet?

Boris The Builder · 11th May 2007, 13:02

Quote: (Originally Posted by Woz)

An O ring is the wrong seal for the application. Until they sort that out, then the Boris's lid will leak. Everything being done to try and solve it so far is a bodge. Re-jig the tooling and fit a chevron seal.

And what do you know exactly? You obviously have extensive indepth knowledge of the Boris dome design so would you you care to elaborate on

a: why this is the wrong application (obviously based on your thorough mis-understanding of the user issue experienced by a few and not the many - which is not O ring related by the way)

b: what are all these bodge fits to the problem that you do not understand?

c: explain why a chevron seal will remedy the issue that you still do not understand

d: do you have any kind engineering credentials from the internet that would enable you to mis-apply a chevron seal to a unit that you quite possibly, based on your comments, have never examined?

Woz · 11th May 2007, 13:11

I've stripped a few Borises down.

My background is designing pressure vessel doors for the end of pipelines. 48" class 1500 ones. And the main problem was not sealing at high pressure but at low pressures. We spent about £25k on designing a seal that would do both and had patents to cover it. The problem with an O ring is it's not designed to seal like a gasket and be compressed but it's designed to try and "flow" up the gap between components. If you try and seal it like a gasket the point contact you get on an O ring means that you either have to apply a suitably large force to compress it and have a suitably stable component to do this with or alternatively use either a softer material or ideally a seal that is designed to seal at low pressures.

The Boris lid isn't dimensionally stable enough or made from strong enough material to do the functions required by an O ring to compress properly and seal effectively. So a choice of a different seal would be a much better idea than putting a larger O ring in. There's only so much force you can put on an O ring the way the Boris is designed- too much interference and you can't get the lid on, too little and it doesn't seal. If the tolerances are out on the lid then you can't maintain the pressure and it leaks. Simple.

11th May 2007, 13:02	#11 (permalink)
Boris The Builder New Member Current Rebreather/s: Ouroboros Other Rebreather/s: Join Date: Nov 2006 Location: UK Posts: 29	Re: Has anyone upgraded their O rings yet? Quote: (Originally Posted by Woz) An O ring is the wrong seal for the application. Until they sort that out, then the Boris's lid will leak. Everything being done to try and solve it so far is a bodge. Re-jig the tooling and fit a chevron seal. And what do you know exactly? You obviously have extensive indepth knowledge of the Boris dome design so would you you care to elaborate on a: why this is the wrong application (obviously based on your thorough mis-understanding of the user issue experienced by a few and not the many - which is not O ring related by the way) b: what are all these bodge fits to the problem that you do not understand? c: explain why a chevron seal will remedy the issue that you still do not understand d: do you have any kind engineering credentials from the internet that would enable you to mis-apply a chevron seal to a unit that you quite possibly, based on your comments, have never examined? __________________ Boris The Builder Do not go where the path may lead, go instead where there is no path and leave a trail! - Ralph Waldo Emerson
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11th May 2007, 13:11	#12 (permalink)
Woz Custom Title Allowed! Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: Jun 2005 Location: Nottingham Posts: 185	Re: Has anyone upgraded their O rings yet? I've stripped a few Borises down. My background is designing pressure vessel doors for the end of pipelines. 48" class 1500 ones. And the main problem was not sealing at high pressure but at low pressures. We spent about £25k on designing a seal that would do both and had patents to cover it. The problem with an O ring is it's not designed to seal like a gasket and be compressed but it's designed to try and "flow" up the gap between components. If you try and seal it like a gasket the point contact you get on an O ring means that you either have to apply a suitably large force to compress it and have a suitably stable component to do this with or alternatively use either a softer material or ideally a seal that is designed to seal at low pressures. The Boris lid isn't dimensionally stable enough or made from strong enough material to do the functions required by an O ring to compress properly and seal effectively. So a choice of a different seal would be a much better idea than putting a larger O ring in. There's only so much force you can put on an O ring the way the Boris is designed- too much interference and you can't get the lid on, too little and it doesn't seal. If the tolerances are out on the lid then you can't maintain the pressure and it leaks. Simple. __________________ Still punting shiny diving tatt to gullible divers www.kitfondle.co.uk Last edited by Woz : 14th May 2007 at 10:50.
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