100cf vs. 90cf vs. 80cf: Big difference?

[reeldive]

Beware of cylinders filled by Paint ballers. I saw one Luxfer AL80 filled to 3600 psi. Can you hear the BOOM yet?

 

[FredT]

The "cheap" gages used on SPGs and many fill stations are ± 2.5% of full scale. For a 5000 psi gages that is ± 125 psi. There are several classes of gage much better than that, and a couple worse. The mechanical gages are most accurate at the middle of the scale, and can be expected to be off by at least the tolerance on each end. To accurately measure a 3000 psi line, the best gage to choose is either a 0-5000 psi range or 0-6000 psi if going to fill over 3400 psi bottles. "Better" gages can be had with varying accuracies to ±0.01%, but they'll cost about as much as a mid size car. Simple recalibration of the "good" gage is about $1500-3000. Most folks pay for the accuracy they need. Even the "cheap" gages are pretty repeatable if you can compare them to a "reasonably good" gage, but absolute accuracy sucks.

FT