SpudFiles

Can anyone that has used a similar air tank help me with what max pressure I may be able to use safely?ive had 100psi in it and expect to be able to get 150psi,anything past 120 is unchartered waters for me,also will the compressed air change pressure in different temperatures I'm sure it does but how much?
The tank is made of a 40cm/4cm length of approx 1.5mm auto exhaust tube with 2mm end caps MIG welded at each end aswell as the bronze fitting bronzed on and an anchor nut MIG'd on the inside of the other end cap for the schrader valve to be screwed into.
Can anyone give me an estimate of what max pressure I may be able to use?

Looks / sounds to me like the lowest rated part is the schrader valve IIRC 315PSI ??? No one can vouch for the welding...

You see muflers blowing apart from a backfire, so it's a guess what it would hold. I've just recently made a similar looking tank out if galvanized pipe...that sucker aint letting go too easy.

I have a prototype galvanised HPA tank that holds up to 100 PSI (safely).

What you need to understand is the effects of pressure on it's cylinders - Thin walls and large volumes don't mix... Thick walls and small volume permits higher pressure. Welding is also a no-go for me.

Go to bunnings, buy THICK threaded metals like brass or cast iron and modify them to accept two valves (shrader and firing valve). It's safer!

I would be vary apprehensive of using a tank like this at any pressure anywhere near a person while pressurized. Flat ends are generally a no go, each time it is pressurized the metal flexes which fatigues the weld, so after numerous fillings it may let go with no warning at all, even at 100psi there are hundreds of pounds of force on the end. If I was to even consider using a tank of that sort I would not withought hydro testing it. Il

wdr0 wrote:I would be vary apprehensive of using a tank like this at any pressure anywhere near a person while pressurized. Flat ends are generally a no go, each time it is pressurized the metal flexes which fatigues the weld, so after numerous fillings it may let go with no warning at all, even at 100psi there are hundreds of pounds of force on the end. If I was to even consider using a tank of that sort I would not withought hydro testing it. Il

I agree. Well said.

Pressure is like electricity. You cannot see it therefore you MUST be extra careful around it.

http://www.engineersedge.com/calculator ... t_calc.htm

Keep in mind working pressures are much lower than burst pressure.

If you must use this cylinder...

Your ends are thicker than the walls, that's a plus. The welds are on the person who did the welding. Try pressurizing with water and measure the length and diameter in several spots to see if it changes significantly... Not a good sign. Be careful. Wrapping with something to contain shrapnel might help.