Welding Tips and Tricks

You can give these guys a shot. I've used their location here a few times and they're always good.

http://www2.mathesongas.com/storeLocato ... pt=4&ra=25

That's a tough spot you're in. Hope you're able to find someone to help out.

Arno wrote:...Is there no gas seller in the US region yet that carries the newer style 300bar/4350psi bottles like are getting more common here in Europe?...

While I haven't seen the composite bottles yet, I have ordered a nitrogen cylinder that could be filled to 4500PSI. I think the MAWP on it was 6000, but regulations restricted it to 4500. I also never used it. It proved a waste of time, as the idea was to pre-charge a system for a 9680psi test, and the pump we had for the job could accomplish the "pre-charge" faster than setting up the bottle then swapping in the pump.

Steve S

airrj wrote: So whether or not the cylinder can pass the test at 15 years it is scrap. This really adds to the cost of unit compared to aluminum or steel that can go for many more years.

The composite ones are fairly new and specialised though and mostlly meant for easier portability. Fairly expensive too, but could probably mean the difference between being able to reach some locations or not.

They do tend to have a hard life being lugged around a lot (which is also why the protective pieces are on the top and bottom), so I suspect many of them will already get damaged enough in their lifecycle that they won't even need to last that long.

Also in many cases they are operated on an exchange/rental basis, so the end user doesn't really see the lifespan (or lack thereof), but they just end up more expensive to rent if they need to be replaced sooner..

Plain steel cylinders are still the norm though, but there the 300bar units are making inroads too.

Bye, Arno.

The 5 year hydo test has three outcomes, scrap, safe for indicated pressure and plus. The test involves measuring deformation of the cylinder under pressure and then measuring the yield volume after pressure is relieved.

Plus means 10% overfill pressure is allowed. My rudimentary gouges show 2500 psi. There is still a generous safety factor.

Steel at 2265 indicated lasts a very long time. I've had oxygen cylinders from the 1940s come through..lots of hydro stamps for sure.

If it works, why not?

I have a favorite bottle I use for helium, exclusively, for helium leak testing. It's original test date is March 1919, and the neck ring reads, "Army Air Service Balloon."

It's currently out of date, and I intend to have it retested in March of 2019, and have the recertification date stamped directly under the original test date, for a "century cylinder".

Steve S

Otto Nobedder wrote:I have a favorite bottle I use for helium, exclusively, for helium leak testing. It's original test date is March 1919, and the neck ring reads, "Army Air Service Balloon."

It's currently out of date, and I intend to have it retested in March of 2019, and have the recertification date stamped directly under the original test date, for a "century cylinder".

Steve S

That's pretty sweet man