Screw lock for 100% oxygen, where to get?

[Agro]

A have an adapter including check valve. Inside is a screw which I have to lock a littel bit. Loctite would be a solution but I found no Loctite which is allowed to be used in 200 bar oxygen. What can you recommend? Any experencies? Thanks a lot.

 

[happy-diver]

Peen it over mate with a nail or something!

 

[iain/hsm]

A have an adapter including check valve. Inside is a screw which I have to lock a littel bit. Loctite would be a solution but I found no Loctite which is allowed to be used in 200 bar oxygen. What can you recommend? Any experencies? Thanks a lot.

From experience you won't find anything that a manufacturer will say "Certified for 200 Bar Oxygen Service". The market need is too small and the cost to test and certify ie BAM testing is too great.

You can find "BAM tested" on oxygen but the testing is 20 maybe 40 bar upper limit
Note by your "which is allowed" I have assumed you mean BAM Tested as your Swiss origin.
Also most will not be suitable for your small thread,

Again to define a small thread a 3 to 6 mm metric thread male into a blind female block
and not a open thru threaded hole.

I would suggest Loctite 290 in a small 5Ml bottle will set you back around £10

If you need a BAM certified high strength Loctite with a BAM approval for low pressure oxygen
then something like Weiconlock AN 302-75 and you will pay over £100

Failing that you have Loxeal 83-21 the Coltri of Italian sealants its BAM tested but to 20 Bar
At the bargain price at £90.00

Loctite 271 is BAM tested but its not suitable for fine threads IMHO
Loctite 245 also as above
Loctite 567 has a BAM approval for low pressure but only suitable for M10 and above threads
Loctite 270 also as above but on say M6 maybe but your at a 3 Nm (290 inch pound) torque

So we're back to £10 and Loctite 290 in a small 5Ml bottle I guess.

Used on many pure oxygen compressor and boosters 100's to my knowledge for fine threads only up to 6mm and only in blind holes. Others here may disagree but only at the diving instructor level. lol

 

[broncobowsher]

Screw, as in machine screw? Would it be possible to use a jam nut (or set screw)? Mechanical locking instead of chemical locking.

Having a hard time trying to picture what you are working with. My mind is thinking of a half dozen different interpretations of your problem.

 

[Agro]

I'll post a photo within next days

 

[-JD-]

I was thinking a couple wraps of O2 Service teflon tape may do the trick as a soft-lock if it just a vibration issue you are combatting.

PTFE Seal Tape - Oxygen Service

Premium quality full density 1/4-inch wide PTFE thread sealing tape suitable for use with Nitrox, Trimix and Oxygen breathing gas handling equipment commonly encountered in support of SCUBA diving applications.

www.divegearexpress.com

 

[Agro]

Sorry, I can take pic tomorrow.

The product has to lock the screw a little bit only, so it does not matter at all if specification sais for smaller or lager threads only, it will work anyway.

Weiconlock AN 302-75: I found no data sheet saying it's OK für O2. Am I blind? I can get this product in a small amount for 40 Euro, that's perfectly OK. But does it work on high pressure O2?

Same on Loxeal, I found no information about O2. Am I blind?

Loctite 290: Data sheet sais NOT suitable for pure oxygen. They are not speaking about high pressure oxygen, but oxygen. Which semms to be oxygen at ambient pressure.

Seems to difficult to finde a product.....

 

[happy-diver]

Here it is in the language of looking where a slight peen easily reversed prevents the unscrewing of the pieces

 

[Agro]

Here is a drawing. It is a non return valve. The right yellow screw must be locked a little bit, it has a M13x0.5 thread.

This yellow screw presses on the plastic part on it's left side, it is a Zytel seat out of a Poseidon Xstream Poseidon Zytel Ventilsitz für 1. Stufe XSTREAM Threfor screw only must press very softly on the seat, not dammaging it. So screw sometimes comes loose.

Peening over with a nail or so is not my favourite, don't want to dammage it.

Do you think a bit of teflon tape might work? It's a very fine cylindric thread.

My favourite still is some kind of Loctite but I found none for 300 bar O2. I would even accept 200 bar.

Thanks for your help.

 

[rjack321]

Here is a drawing. It is a non return valve. The right yellow screw must be locked a little bit, it has a M13x0.5 thread.

This yellow screw presses on the plastic part on it's left side, it is a Zytel seat out of a Poseidon Xstream Poseidon Zytel Ventilsitz für 1. Stufe XSTREAM Threfor screw only must press very softly on the seat, not dammaging it. So screw sometimes comes loose.

Peening over with a nail or so is not my favourite, don't want to dammage it.

Do you think a bit of teflon tape might work? It's a very fine cylindric thread.

My favourite still is some kind of Loctite but I found none for 300 bar O2. I would even accept 200 bar.

Thanks for your help.

Who cares about your set screw threads... this zytel part is basically nylon which is not certified for high pressure O2 either - even though it's in the lining of virtually every conventional scuba hose (not the braided types however). Good luck