reubencahn
Contributor
I understand that the valves are nitrox ready, and I would think the tanks, being new are reasonably clean. So are the tanks ready to go, or do they still need to be cleaned?
PST E Series Nitrox Ready ?
- Thread starter reubencahn
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Spectre
Contributor
They are supposedly O2 Cleaned. However I know a few people of the opinion that you shouldn't trust factory o2 cleaning,and should either do it yourself or have it done by someone you trust...
esmiami
Guest
This is a company that has been making all kinds of gas cylinders for 101 years. I'd think by now they know how to make an O2 clean scuba tank.
with ALL THREE of mine, the TANKS are O2 clean from the factory.
The VALVES are not, however, so they say, for more than 40% EANx.
Now in truth are they OK? The valves appear to be (internally) Thermos (I took 'em apart and checked them out) and I saw no problems with them as they came.
Was the "letter" azz-covering? Probably.
I've since PP filled all of them several times without incident.
The VALVES are not, however, so they say, for more than 40% EANx.
Now in truth are they OK? The valves appear to be (internally) Thermos (I took 'em apart and checked them out) and I saw no problems with them as they came.
Was the "letter" azz-covering? Probably.
I've since PP filled all of them several times without incident.
as far as common practice goes, these tanks and valves are fine for pp blending in them right from the factory.
We actually put O2 clean stickers on them when they come in from the factory.
The valves are described as O2 service rated, and O2 cleaned.
We actually put O2 clean stickers on them when they come in from the factory.
The valves are described as O2 service rated, and O2 cleaned.
of my tanks had current VIS stickers on them, and a "storage fill" in them when they arrived. The shop I got them from delivered them to me in the ORIGINAL packaging and shrinkwrap; they didn't even unwrap them until I got there.
I took the letter in the box to be butt-covering on PST's part since they pretty clearly farm out the valve to either Thermo or someone making a darn good clone of one, and it has a nice "Nitrox Only" plate on it....
BTW, the tank neck O-rings on mine appeared to be Buna and not Viton. Not a big deal, but there you have it (the debate on Buna .vs. Viton in O2-service is nowhere near settled; there are valid arguments for both views.... if you want to hear the "other side" go talk to some aircraft folks - they use buna O-rings on O2 connections....)
I took the letter in the box to be butt-covering on PST's part since they pretty clearly farm out the valve to either Thermo or someone making a darn good clone of one, and it has a nice "Nitrox Only" plate on it....
BTW, the tank neck O-rings on mine appeared to be Buna and not Viton. Not a big deal, but there you have it (the debate on Buna .vs. Viton in O2-service is nowhere near settled; there are valid arguments for both views.... if you want to hear the "other side" go talk to some aircraft folks - they use buna O-rings on O2 connections....)
Actually, they are EPDM. (I believe)...
Alot of manufacturers are switching to EPDM from VITON for O2 service. I was told at one point, why, but I dont remember. Maybe someone else has that info...
For example, Aqualung switched a while back to EPDM for their regs, Apeks already has been using EPDM for while.
EPDM is pretty cheap too, not that much more than BUNA, so we switched to all EPDM orings in our shop too...
Alot of manufacturers are switching to EPDM from VITON for O2 service. I was told at one point, why, but I dont remember. Maybe someone else has that info...
For example, Aqualung switched a while back to EPDM for their regs, Apeks already has been using EPDM for while.
EPDM is pretty cheap too, not that much more than BUNA, so we switched to all EPDM orings in our shop too...
Hmmm... might be. Its tough to know; there is no "standard" for color, really. I didn't analyze it...
Buna still has the best abrasion resistance and tensile strength, which are important in dynamic O-rings; of course that's a non-issue with a tank neck O-ring, but its an issue for dynamic ones in valves and regs.
As with all things, there are trade-offs. You get and you give, and there is no single answer.
One issue with EPDM is that it can be tough to find it in other than 70 duro. That's ok for most uses, but where you want a harder O-ring you may have trouble finding it.
Look at some of the published "compatability" charts and you'll see some of the trade-offs. For example, EDPM is listed as "ok" for O2 "cold" (not Lox, but room temp) but unsatisfactory at 200F. Viton is listed as "fair" in the same application. Silicone O-rings, by the way, are listed as "ok" for hot (300Fish) O2, but we all know that silicone GREASE is a no-no for O2-service! That's one that makes 'ya wonder...
There are some head-scratchers in there when you start delving into material compatability issues in real depth....
Buna still has the best abrasion resistance and tensile strength, which are important in dynamic O-rings; of course that's a non-issue with a tank neck O-ring, but its an issue for dynamic ones in valves and regs.
As with all things, there are trade-offs. You get and you give, and there is no single answer.
One issue with EPDM is that it can be tough to find it in other than 70 duro. That's ok for most uses, but where you want a harder O-ring you may have trouble finding it.
Look at some of the published "compatability" charts and you'll see some of the trade-offs. For example, EDPM is listed as "ok" for O2 "cold" (not Lox, but room temp) but unsatisfactory at 200F. Viton is listed as "fair" in the same application. Silicone O-rings, by the way, are listed as "ok" for hot (300Fish) O2, but we all know that silicone GREASE is a no-no for O2-service! That's one that makes 'ya wonder...
There are some head-scratchers in there when you start delving into material compatability issues in real depth....
Yeah, its driving me crazy... Alot of guys think viton is the only way to go for O2 service.
Now, the new standard seems to be going in the direction of EPDM (as far as reg manufacturers go).
Imagine, a customer brought their reg in for O2 cleaning two years ago, and we put VITON orings in, and now this year its EPDM. Its tough convincing everyone that EPDM is better suited for O2 service...
What made viton not any good anymore???
I dont know.
Now, the new standard seems to be going in the direction of EPDM (as far as reg manufacturers go).
Imagine, a customer brought their reg in for O2 cleaning two years ago, and we put VITON orings in, and now this year its EPDM. Its tough convincing everyone that EPDM is better suited for O2 service...
What made viton not any good anymore???
I dont know.
Soggy
Contributor
Just picked up my tanks from the LDS today. The yoke/DIN combo valve that comes on the tank is NOT O2 service rated. On the paperwork, it states in big, underlined, bold letters that it is only good for 40%.
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