How long for a PCP tube's life span

[Ribbonstone]

  I do get to wondering about PCP's and age.  We don't normally really stress the air tubes as we don't normally run them to empty, so it's not like a 0-3000psi cycle, it's more like a 2000-3000psi cycle....but a lot of cycles in a gun's life time.

So, while the 2X2 rule does apply, I still think there is a point where the tube is going to just be kind of "iffy". Won't likely be swelling, stress cycling metal doesn't tend to do that...it tends to make it more brittle (which is why door handles/window cranks in old cars tend to unexpectedly crack or snap in half).

So dude...I really don't know.  Modern PCP's tend toards the lighest weight (thinnest) tanks  with enough of a saftey factor in order to be light enough.  Older PCp's tend to be heavy,and a lot of the weight is in "extra" tube thickness compared to modern rifles.

So...one one side we have folks that claim that PCP tues are "forever" just becasue they fall under the 2X2 rule.  On the other, we have FWB that recommends a pressure tube replacement every 10 years.
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My personal oldest (still in use) is an AA s200 from 2003...so the tube is now 15 years old.

Lucky for me, can still get the part as the rifle is still made.  May be over-kill to replace the tube (and I'll get a complete tube/rear filled gage on the front tube), but at least it is a screw on replacement.


So..  THE QUESTION...where do you stand?

1. PCP rifle tubes, steel/aluminum/ or Titanium, all fall under the 2X2 rule, and should last "forever".  Your great-grand children shouold be able to reseal them and keep on shooting.

2. A shooters typical 20-30 year lifespan (yeah..WISH I had 20 years left in me).  They'll eventually get to be brittle and prone to failure, but last as long as you have left as a shooter.

3. 10 years and replace them.

[Machinist]

I go with #4

Take a look at the tube and see if it's rusty.

Personally I'm afraid of aluminum.

Steve

[Ribbonstone]

So...basically if it ain't rusty, you'll use it "forever" (which would be something between #1 and #2).

[rsterne]

Check every few years for corrosion.... if none, you should be good to go "forever".... providing the manufacturer did their homework....

Bob

[AlanMcD]

I agree with Bob, and would prefer another choice - 4) Depends on how it was used/cared for.

If filled from a dry source of air, well protected, never seriously over filled, prevented form exterior rusting (and of course interior by the dry air) then I go with forever . . .

Do bear in mind that steel dive tanks can be used "forever" providing they pass inspections - the "2x2" rule just exempts the vessels from those checks.  So there is no reason that a properly desinged well treated tube can't last forever.

Personnaly I think FWB's recommendation is self-serving: it gives them a liability out in oretty much all cases, and potentially makes them some money as well.  Great company, but that is overkill.

[Ribbonstone]

I'm thinking that in today's world, they're making them to the minimum thickness in order to save weight. Not that thickness is everything, that's more dependent on what it's made of than how thick it is, but I've a suspicion that weight savingsurge has trimmed the longevity level.

[Taso1000]

Hi All,

I have read that in competitions you are not allowed to use a pressure vessel that is over 10 years old  Does any one know what the reasoning or where they based their reasoning?

Thanks,

Taso

[Gear_Junkie]

The steel tube on my Regal is supposed to be replaced 10 years after the date of manufacture.

[toddbrat]

This brings up a question I've been thinking about. I usually fill from a SCUBA tank filled at a paintball field. It isn't breathable but seems fairly dry. I've also been hand pumping a lot lately and that is pretty humid. I'm concerned about moisture and corrosion and wondering if "airing" the tube out is recommended. I've had both my PCP's torn down but never opened the air tubes.

[Taso1000]

Todd,

What would be cool is if we could find a protectant to apply on the interior of our tubes that was non flammable.  Something like WD-40 Specialist Long-Term Corrosion Inhibitor, Frog Lube, Eezox or even Nu Finish. 

Like during an annual tear down/service.  Clean all the metal parts and reapply our protectant, replace all o-rings and then reassemble.

Maybe one of the suitable protectants could be left to air out for a week or so to allow all the volatile substances to dissipate and then reassemble the air gun?

I have WD-40 Specialist Long-Term Corrosion Inhibitor and Nu Finish on hand but I have read that the WD-40 product gets tacky.  I don't know if that's good or bad.

I guess you could coat the surfaces with silicone grease or krytox/ultimox but I don't know if they will displace moisture or moisture could get under them.

Taso

[RAJOD]

The steel tube on my Regal is supposed to be replaced 10 years after the date of manufacture.

Mine said 10 years too but would be interesting to see how they came up with 10 years.  Why not 8? 7? 11?   Just seems like they pulled it out of a hat.   

I would like to see the tubes of like 20 year old guns they have been around long enough.   Maybe someone  in the forum has a 3000 psi PCP from 1998.   

[Ribbonstone]

Nothing last forever...but we treat them as such. Are lot6s of firearms from 1889 (or older) still shot, but not too many PCP's from 1998....but there are some.

So let's see...what PCP's were available  in 1998?


Aws for air tube3s...if you have one apart, buff in a nice thin coating of silicon grease (like waxing a car)....if the metal is coated, it's not going to rust even if you fill it with water, and "real" Silicon grease has no chance of igniting.

[Gear_Junkie]

The steel tube on my Regal is supposed to be replaced 10 years after the date of manufacture.

Mine said 10 years too but would be interesting to see how they came up with 10 years.  Why not 8? 7? 11?   Just seems like they pulled it out of a hat.   

Agreed.  I've had most of my gun apart, but not the air tube.  Next winter, I may pull it off and lube the inside with a very light coat of silicone grease, just to protect it.  Also, I want to see if hand pumping has caused any issues within the year that I've been doing it.

[Ribbonstone]

Believe or not.

Been onlyhand pumping for better than a decade.  Gave up the tanks about 11 years ago.

Have found rust/corrsion three times, but I can't blame the pump for any of them.

1. Found rust inside a new rifle's tube...must have been "factory" rustas I had nothing to do with it.
2. Found rust/corrsion/curd in the middle of a gauge block a couple of times. But that area is NOT PRERSSURIZED...it's where thre gage eneters though the tube, is o-ringed at each end of the block, so is open to whatever outside ambinat air/rain/mist/dust/sweat/etc/ is out there.
3.Found a ring of rust at the fill end cap. Two o-rings, and evidently the first o-ring leaked while the rear o-ring held pressure, so it was outside air/mist/fog/rain/sweat/etc. leaking in rather than anything to do with the pressuized area.

BUT...folks like to make a great big deal about the possibility of moisture and pumps....which is OK by me, as we all seem to have to be fixated on something or other.

[RobertMcC]

My Kral has a expiry date on the tube.

[toddbrat]

Believe or not.

Been onlyhand pumping for better than a decade.  Gave up the tanks about 11 years ago.

Have found rust/corrsion three times, but I can't blame the pump for any of them.

1. Found rust inside a new rifle's tube...must have been "factory" rustas I had nothing to do with it.
2. Found rust/corrsion/curd in the middle of a gauge block a couple of times. But that area is NOT PRERSSURIZED...it's where thre gage eneters though the tube, is o-ringed at each end of the block, so is open to whatever outside ambinat air/rain/mist/dust/sweat/etc/ is out there.
3.Found a ring of rust at the fill end cap. Two o-rings, and evidently the first o-ring leaked while the rear o-ring held pressure, so it was outside air/mist/fog/rain/sweat/etc. leaking in rather than anything to do with the pressuized area.

BUT...folks like to make a great big deal about the possibility of moisture and pumps....which is OK by me, as we all seem to have to be fixated on something or other.

I'll be the first to admit I don't change the desiccant as often as I should in my hand pump and I usually pump outside where I'm shooting instead of taking it in the house where it is lower humidity--and a lot cooler. I do like the thought of a light coating of silicone grease on the insides.

It is also great to hear that hand pumping in Louisiana hasn't really shown any indications of corrosion where it seems it would.

Of course, all of the swampland there does tend to keep the moisture in the ground and out of the air 

[Ribbonstone]

Most folks won't like how I pump fill....it takes a long time.

  Connect pump, put in 50-60 pump strokes.
  Bleed the pump and disconnect hose. (which blows out the little moisture trap built into nearly every pump).
  Give it a few minutes to cool down...go do somthing constructive for 5 or 10 min.
  Hook up pump and put in another 50-60 pumps.

Repeat as many times as you need to get the tube full.
 

[AlanMcD]

With that pumping routine, you won't be letting any liquid water make it's way into the gun.  The key is to keep the air charge cool (by letting the heat of compression dissipate into the large aluminum base of the pump) and then the water will condense in the pump base and not enter the gun.

The 50-60 strokes, with cool down time in between is the key.

[toddbrat]

This all makes me feel better. My Urban is almost 1:1 shot to pump strokes with my Benji handpump. Only fill to 2k psi, get 30 shots then about 31-32 pumps back to 2k. Sounds like most of the moisture should be in the pump base.

[RobertMcC]

My hand pump got a moisture trap on it. But I keep the dehumidifier on in the basement all the time.