Pyramid Refurbished Air Tank.

Hydro-static testing takes tanks to 5/3 their rated pressure. It is not destructive...destructive is a powerful word and I have read no literature confirming that destruction occurs when Hydro-static testing CF wrapped tanks. In fact...this method of testing is generally known as non-destructive testing...

1725388064561.png


So yea, I have a bone to pick with the choice of words, and all the flopping around from it applies to this, to it applies to that, or it only applies to current testing...

High pressure Vessels / Tanks are generally designed at minimum 2.4x their yield, meaning a Hydro-Static test is pressurizing the tank far below the calculated yield.

4,500 psi x 2.5 = 11,250, meaning the tank shouldn't yield at the tested 5/3 rating which is 7,500 psi, far below the yield. If the tank does yield, then yes, it is destroyed, which is the purpose of the test, to make sure the integrity remains as designed.

So in other words, if the test IS in fact destructive, then your tank failed the test, if the test is NOT destructive, your tank passed.

-Matt
 
Last edited:
So after a suggestion here made by a Member, instead of Buying a Used tank from Ebay for less than $100.00, I went ahead and ordered a Refurb 90 ci tank from Pyramid. It looked to be in Great shape. The paint on the neck of the bottle has some scratch marks "probably from being removed" but otherwise looked great. The Fresh New Seal is there stating that it had been thoroughly tested to 7500 PSI is there and ready to be Refilled! Yayy Me! Unfortunately It loses 1000 Psi overnight. Now using a Small Pump to air it up is time consuming. From empty it took over several hours only filling to a certain Temp and then allowing time for the pump to cool down. Now I was Told when I ordered it that "It will be all ready to go! You have a Pump and the Correct Filters so Air it up and Have Fun!" I did that. And it Leaks. So back it goes. I am waiting to hear now from the usual commentors about how I somehow "Misinterpreted" what I was told? LOL How could it have passed a 7500 PSI Certification and not been diagnosed with a leak? Riddle Me that! lol
I hope that "Balanza Tres" approves this message.
That sounds to me like one of the valve o rings may have failed. Should not be too much of an issue for pyramid to correct. I don't think you misinterpreted anything.
 
  • Like
Reactions: Chief Ten-Beers
Specifically the wording in blue; all pressure vessels with high pressure gasses must be inspected and tested every 5 years, steel, aluminum and CF are all included.

Private ownership and non-DOT transportation are exempt.
This ONLY applies if the owner has a compressor. If owner is having a shop fill the tank than owner must adhere to DOT, local laws & regs & the shop's own criteria for how they approach things.
 
Interesting. I called Pyramid and the Guy said that they "Fully Test the Unit". I guess this one missed that step?
At least the return Tag is on the way.
Ya, bout have to it's back to liability .. if they admit there action was the issues you maybe using that to sue them .

Always remember ... It's everything else's fault but your own .😇. Never admit to anything or say your sorry.
 
I've accumulated a few CF tanks in the past year, both new and used. No issues with the actual tanks whatsoever. I have no qualms buying used tanks or the cheap eBay offerings. I fill mine with an Omega Supercharger compressor so I don't care about DOT certs. The valves are the item I would describe as 'you get what you pay for'. The JB TJ3 is my favorite so far.

New:

-3L Acecare from Amazon. I put a Scandinavian Arms valve on it. No issues.
-2L Tuxing from eBay. Cheap Palm Beach Air valve. Bottle gauge quit working but valve operates fine.
-6.8L Omega from AoA. Standard Omega valve. DIN adapter O-ring blew out. Easily replaced with dive shop O-ring kit.

Used:

-9L Air Venturi from AGN classifieds. Came with original valve from 2014. Valve was stiff and the fill gauge was over 50bar off. I put a Joe Brancato TJ3 valve on it. No issues.

Hope this helps
 
  • Like
Reactions: Chief Ten-Beers