Buoyancy of Steel 100's?

[RecklessAmateur]

Hey, so here's puzzler of the day. I have two steel 100's of different makes and I'm convinced they have different buoyancy characteristics (one of them is probably 15 years old, one brand new). Can anybody point me to a site or any info that would help establish once and for all how buoyant each filled and empty? I'm sure I'll need to figure out the hieroglyphics of various numbers stamped on the tanks--any guidance about what I should be looking for? Thanks in advance.

 

[Scared Silly]

A fairy accurate chart: Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

 

[spectrum]

Your new cylinders are probably XS Scuba and the oldie a PST. If so new one will be about 1.5 pounds more negative. 15 years suggests the 3500 PSI DIN only version. Come back with brands, pressures etc and we can pinpoint it. If there is a Faber in there it could be VERY negative.

Pete

 

[Diver0001]

The internal volume is the same so just weigh them. If there is a difference in weight (which is quite possible) then google "density of steel" or something like that and work out displacement variance between the two tanks and it should give you a good idea of where to attach a trim weight, if necessary.

R..