Guide for Building a Bowling Ball Mortar.

[little seacoast]

Mooke, The neck of the tank itself seldom fails, thicker metal and smaller diameter. Sounds like the valve itself failed on yours.  Most cylinder failures that I have seen have been in the sides of the tank and as DD pointed out, the pressure in a mortar is greatly diminished as the gases leave the powder chamber.

[flagman1776]

 

[Double D]

The 3A or 3AA is the material,  the 1800, 2100, 2400 or whatever is the pressure rating.  None of this tells what the tank size is.  I think measuring will be the only way to determine the diameter. 
 
The "testing" is "hydrostatic testing" where the tank is immersed in a water jacket & after zeroing the guages, an overpressure is applied, then depressurized.  If the permanant expansion exceeds 10% the cylinder is deemed to be metal fatigued & condemned. 
 
http://en.wikipedia.org/wiki/Hydrostatic_test
 
I am conflicted about using condemned fatigued cylinders.  I know the thinest part of the cylinder wall is likely the most fatigued place but I do not know enough about it to feel comfortable.

Actually that information does point to dimensions.  Here is the entry we have in the reference sticky's on bowling ball mortars and pressure tanks with nominal dimensions.

 I can understand you concern about condemned tanks.  Understand how ever the cannon is the powder chamber.  This tank is not a the cannon, it is simply an expansion chamber and ball holder attached to the chamber.  The down side is we really don't know the pressures exerted again the walls of the tank when the gun is fired.   

   

A bowling ball gun with proper windage would need a minimum bore of 8.815 inch.
Circumference of a bowling ball.  Max 27.002 inches.  27.002 xi .31831 = 8.595 maximum diameter of a bowling .  (8.595/39)x40= 8.815 inches http://www.topendsports.com/sport/tenpin/dimensions.htm

The Pressure tank need to make the expansion chamber for a bowling ball mortar for is the 300 CF, DOT 3AA2400 made by Taylor Wharton. http://www.taylorwharton.com/assets/base/doc/products/cylinders/TW1102_StandardHighPressure.pdf

[GGaskill]

My understanding of cylinder inspection is that there are two phases.  The first is a visual inspection where they look for rust, lack of paint, etc.  The second is the pressure test.  A cylinder can fail either part. 

[flagman1776]

 

[smokemjoe]

 Mine tank was a reject because someone struck a ark  on the side of the tank.  The company burned a hole in the bottom for it couldnt be used again.