TargetTalk

Both of my cylinders are leaking air now.

Taken off pump, start hissing, screw on pistol, shoots OK, no leak.

I think both cylinder seals need to be changed.

Need recommendation for the three prong wrench used to open cylinder.

Would the three prong wrench used to open watch caseback work?

of course, for safety, I will release all pressure off cylinder before opening the cylinder.

wow, that is a long run for a short slide.

Isn't there a three-prong wrench for opening those three hole screw?

yes, there is the one that you made, it's easy.
there is the more difficult task not damage of the cylinder surface and cylinder shape
when unscrewing the cylinder cap, be careful
sorry, it is easy to damage the anodized layer and to make a sharp notch

seamaster wrote:Would the three prong wrench used to open watch caseback work?

No, the watch case opener does not have the torque to open the valve end of the air cylinder.

You can ask a local machinist to make you the 3 prong spanner wrench with a long handle or
simply ask Steyr Sport to see which wrench they're using to assemble their cylinders.

It seems if you can open them up, you can do a visual inspection. Why can't these be visually inspected, hydro-tested, and recertified every couple years like scuba tanks?

They could, but the rules don't have an exemption for recertification. Date of manufacture is all it says.

The other issue is that every vendor's cylinders are different. If someone were to offer it as a service, they would need a collection of different tools, seals & fittings to do the testing. It's doable, but a bit of a pain to set up. The manufacturers could do it, or even recylcle valves & gauges on new cylinder walls.

Step 1 would be to get the ISSF to formally allow it. Given that the vendors make lots of money selling cylinders to everyone, they would much rather sell a cylinder for $200 than charge $50 for recertification. I have heard more than one person claim that the 10 year limit is primarily a money making dodge and has nothing to do with safety. Morini & Hammerli had no problem certifying their cylinders for 20 years before the rules change, so there is no technical reason why it couldn't be done.

If (as some people claim) the real problem is the number of cycles of expanding & contracting an aluminum cylinder under goes, then they should install counters that track the number of times a cylinder has cycled through a significant pressure change. A 5 year old cylinder that has been fired down to 80 bar and refilled every week is far more likely to fail than a 20 year old cylinder that is topped off after every practice session.

Above all, 10 years is a mere administrative act.
Cylinders, which so far have been ruptured by the quality of the material, the process of producing bad or poor design. In a well-designed cylinder should be much lower operational than the yield strength of the material and its durability can not therefore decide the number of pressurizing cycles. During long time operation cylinder will be under the influence of external mechanical damage and corrosion attack of the outer and inner surfaces. It's damage are very well visually observable.
On the other hand ISSF rules are clearly specified. We do not create it, we are only respected even if they are sometimes strange.
Boundary of 10 years is very very safe until it is pointless. And it is unsurpassed for ISSF competitions. That is the reality.

P.S. Air pistol cylinders can in no way compare scuba diving tanks, whose stress is a much greater and destruction and their consequences are much more serious.

kevinkunkle wrote:http://www.network54.com/Forum/79537/th ... isassembly

WECSOG at its best! All he needs is a Dremel.

Got the cylinder opened tonight with that "three-screw through wood stick" wrench technique.

Outer cap seal was cut, but I doubt that is the cause of the leak, because prior to remove the cap, I did a water leak test. Leak was coming off center, not perimeter of the cap.

How many seals are there?

http://www.targettalk.org/viewtopic.php ... 50#p263940


from original LP10 manual

Greetings All,

Since I like taking things apart to see how they work, this post has been most tempting.

Only two O-rings I can see in the cylinder.

Since the O-rings do all the work of sealing, I wonder what torque is recommended for refitting the end cap?

Also, what lubricant, if any, would be used on the threads to prevent galling?

Cheers,

David

How much torque?

A lot !!

Used three prong through wood stick technique. Hard to line up all three screws, was able to line up two prongs. Take a lot of torque. Enough to make hand blister via rubber pad grip on my two hands.

Replaced seals. Working great, pressure up to red line, no leak on water test. Shoot vigorously.

Do not overdo it with the torque. Tightening adds to the stress from cylinder internal pressure. Be careful.

Torque required, I was talking about opening. Steyr OEM cylinder is very tight. Takes hand blistering torque to open it.

To recap it, hand tightening is with proper seal is very adequate.

Note: Rubber is incompressible. Poisson's ratio is very high

pbrejsa wrote:Note: Rubber is incompressible. Poisson's ratio is very high

True. But it is deformable to match the sealing groove. Once that's been achieved, no more torque.