O-rings

[Nuke Power]

David,
Whe selecting o-rings do you select an ID of the same dia as the piece that is going to go through it or do you select it one size smaller to ensure a good seal. Also what material have you found to work best with regards to propel resistance... viton,silicone..?

[subbie]

Might I suggest a trip to the Parker site and download their handbook?
Quite informative...

[Kazzer]

Might I suggest a trip to the Parker site and download their handbook?
Quite informative...
Could you please post the URL for Parker

[Nuke Power]

i prefer the easy answers. Meriman knows the answer. Besides I have been looking through an 85 page manual on the subject and the damn thing seems to cover everything but that. Its easy on the job you just look up the mil spec number and it comes in the mail or you sneak one out of the O-ring kit. Unfortunately I have not found an o ring kit that carries them that small.

[Albion]

depends if it is internal seal external or face to face.

if you are using an o ring to seal the inside of ma tube say 40mm id. then you would need a 40mm od o ring, say it was 3mm section then the groove in the internal part would need to be maybe 2-2.5mm (dependant on manufacturer data.

[Nuke Power]

Look guy I am not an o-ring idiot here. I am only trying to answer 2 questions here. One of which only experience can answer since most companies do not use propel in a manner such as our.

[He Who Shall Not Be Named]

What a load of crap!

Just smash the O-ring in there till you get a seal. Done. Finished. Why make Rocket Science out of it.

You people!

So much fails to get done because people make such a big, hairy deal out of the many steps needed to assemble a physical object; to their way of thinking, things have to be just so.

Don't over-think/over-intellectually engage with your work. If you do you'll get bogged down in exacting industrial standards and practices to the point where you won't get a god-damned thing done.

Sometimes you are better served just plowing into the work, identifying the 'right way' as you go through the process of invention, assembly, and use.

Got a problem with the above ethic? Let's compare work -- we'll see who has operational stuff and who still has a pile of unassembled sub-assemblies and unused hardware.

I have spoken ... so let it be written!

(insert crack-of-thunder sound effect here)

David,

[jeep4grog]

I agree with Dave here... ( I know...:D)

But for those of you that want a suggestion on size, match the ID and add .5mm or so to the OD. Silicone has pretty good elasticity and will compress well. I don’t see any issues with Propel since the contact time will be minimal (ie: hours not years) over the life of the O ring. I generally replace these once a year anyway. They are cheap.

Buna and Viton O rings have a higher durometer and don’t compress as well. Compositions like Teflon encapsulated silicone are very hard and don't compress well in this type of application. They might actually start stress fractures in your tube.

I have 28 years in pharmaceutical manufacturing maintenance (and 5 years in the Navy afloat) and I think I have seen every solvent, acid, or nasty chemical ever used...

[Nuke Power]

The dark side is the right side! DOnt you know David is the Sith lord? sheesh!

David why in that long drawn out penis contest could you not at least answered the little question I have. I am basically needing a pushrod seal cast into the butt of my missile. The point of the question was to prevent myself from ordering 50 of the wrong type of O-ring, since they come in packs of 50!
Oh and I agree david.

[He Who Shall Not Be Named]

The dark side is the right side! DOnt you know David is the Sith lord? sheesh!

David why in that long drawn out penis contest could you not at least answered the little question I have. I am basically needing a pushrod seal cast into the butt of my missile. The point of the question was to prevent myself from ordering 50 of the wrong type of O-ring, since they come in packs of 50!
Oh and I agree david.

Why didn't you say so, you ****!

Make the missile nozzle from 1/16" brass rod, bored out with a hole of the correct diameter (between .010"-.030") for the high flow rate needed for a missile. Seal the outside of the nozzle using a 1/16" wall, 1/16"i.d. Buna-rubber O-ring affixed within a grove of the charging/launching adapter.

Idiot!

David,

[toppack]

This is where I get my O-rings. Come in varity-size packs, low cost and are great quality:
(They may not have any with 1/16" I.D.) A flea doesn't have a b-Hole THAT Small! :D
(Not that I'm a Flea b-hole expert or anything.) :D
See Link:
http://search.harborfreight.com/cpisearch/web/search.do?keyword=o-rings&Submit=Go

[Nuke Power]

I order nearly everything through McMaster Carr. I think they have teleporters. Their shipping is so fast it would make Capt Kirk jealous.

[He Who Shall Not Be Named]

This is where I get my O-rings. Come in varity-size packs, low cost and are great quality:
(They may not have any with 1/16" I.D.) A flea doesn't have a b-Hole THAT Small! :D
(Not that I'm a Flea b-hole expert or anything.) :D
See Link:
http://search.harborfreight.com/cpisearch/web/search.do?keyword=o-rings&Submit=Go

http://www.mcmaster.com/

[Albion]

Look guy I am not an o-ring idiot here. I am only trying to answer 2 questions here. One of which only experience can answer since most companies do not use propel in a manner such as our.might want to ask the question better next time then:rolleyes: