Empty Tanks???

[NW Dive Dawg]

Aren't you in "Don't Tell" territory now?

I'm basically in a "probably best not to drive up my road without calling first" territory. WA is now a can't buy or sell AW's state..... but possession is not prohibited.

7" diameter target at 200 yards (ok, 6.5" for steel and 6" for AL once you subtract the wall thickness). You could do it with the issue iron sights.

My M1A is already zeroed for 200 yards..

PS...... One other thing to consider on this thread is "toning" the tanks. For example, if you have two basically identical Luxfer or Catalina AL80's and you know that one is full and not sure about the other, you can just tap the tanks with a wrench or hammer and if the "unknown" tank has the same tone as the "known" full one.......you can be pretty sure that the unknown one is full.

Not saying at all that this is a safe way to confirm status but it can be an indicator.

 

[Still Kicking]

My quick skim of it doesn't show any official mention of lubricating the valve thread.

Luxfer says light lubrication is "essential" and all the PSI instructors I've met have recommended it -- not that any of that is necessarily based in science. I guess it comes down to take your pick.

From Luxfer's Scuba Cylinder Visual Inspection Guide:

"The application of a small quantity of lubricant to the valve threads is essential forthe proper care of the valve and cylinder. We recommend that only Dow CorningCompound 111 be used on valve threads.Only a very small amount of the lube is needed, and only applied at the bottom ofthe valve threads. The lubricant will ride up the threads as it is installed. We onlyrecommend this lubricant since it has proven compatible with cylinders and valves,doesn’t add any grease or oil to the cylinder, is safe to use, and helps prevent galvanic corrosion."

https://www.galiso.com/Training/mobile/pdf/Luxferscbaguide.pdf

 

[lowwall]

If you can't reach the cue ball, maybe try a bridge instead. Or a .22.

Speaking of which, I've played a game after hours at the now defunct Beverly Hills Gun Club (a 50' indoor range) where we rolled out a golf ball and three or four of us tried to keep it from coming to rest with our .22s. I like to think my M41 and I did pretty well.

 

[Tanks A Lot]

Luxfer says
.....
helps prevent galvanic corrosion."

Luxfer is not alone, Catalina says the same, for the very same reason (Valving of SCUBA (Air) Cylinders 2005):

Apply a small amount of lubricant, Dow Corning Compound 111, to the end of the valve and the leading 2 to 3 threads of the valve. A small amount of lubricant has been found helpful to reduce galvanic corrosion in the threads of the cylinder.

I disagree with both, as the reasoning is flawed for two reasons.

1. The lubricant would have to sit between the the cylinder threads and valve threads to prevent any galvanic corrosion. On a typical M25x2 valve at 200 bar, you will see around 1 ton of weight pressing the valve outwards. You probably have 9 to 11 threads engaging, depending on which valve/cylinder combination. Let's say each thread has to hold 100 Kg of weight. Good enough for an armchair calculation. With 100 Kg of weight, most if not all of the lubricant will get squeezed out of the way and metal to metal contact will still happen.

2. Galvanic corrosion doesn't just happen if two different metals touch each other. You need something to make those electrons flow, water is excellent for this. This is why you will see nearly all galvanic corrosion on the very top of the cylinder, where aluminium, brass and water meet.
As I explained above, lubricating threads is an excellent way of trapping moisture in there, not preventing galvanic corrosion, but actively promoting it.

The only time galvanic corrosion on un-lubricated threads was of interest to me was when I received a batch of cylinders that ingested lots of saltwater. They had been destroyed in less than 6 months after their visual. The aluminium was literally glued to the valves.

 

[greeniguana]

"Small quantity of lube"

 

[BRT]

They don't need to be lubed. I have never lubed valve threads and I service many hundreds of them every year.

And when the threads fail or the o-ring sealing surface corrodes away just sell them new tanks!

 

[Tracy]

And when the threads fail or the o-ring sealing surface corrodes away just sell them new tanks!

I mean, you could, but that doesn't happen.
It is more apt to happen because of lube on the tank threads than from lack of lube.

 

[BRT]

I mean, you could, but that doesn't happen.
It is more apt to happen because of lube on the tank threads than from lack of lube.

You are going to tell me that you have seen thread failure because of lube? After a long lifetime of building and fixing I'm not buying in. I have seen tank thread failure from lack of lube. As well as failure of many other threads from lack of lube.

 

[Tracy]

You are going to tell me that you have seen thread failure because of lube? After a long lifetime of building and fixing I'm not buying in. I have seen tank thread failure from lack of lube. As well as failure of many other threads from lack of lube.

Yes
Cool story, Your doubting me will definitely keep me up at night.

 

[Tanks A Lot]

....I have seen tank thread failure from lack of lube....

I'm genuinely curious of how that has happened. My experience after servicing nearly 10000 cylinders is the exact opposite for the above outlined reasons.
If you wouldn't mind detailing on how a cylinder thread failed because of the lack of lube, I'd appreciate that.