Air scrapes the hose wall. A small ID with a large nozzle makes turbulence and dumps PSI before the tip. Gauge at the pot then reads high while the steel stays dirty.
Typical loss on a working length (order of magnitude)
| Hose ID | #4 nozzle | #6 nozzle | #8 nozzle |
|---|---|---|---|
| 19 mm (3/4 in) | 3.5 PSI | 11 PSI | Do not use |
| 25 mm (1 in) | 1.5 PSI | 4.5 PSI | 9.5 PSI |
| 32 mm (1-1/4 in) | 0.5 PSI | 1.5 PSI | 3 PSI |
| 38 mm (1-1/2 in) | Negligible | 0.5 PSI | 1.5 PSI |
BLAST APEX blast hose is 19 mm ID as the stock listing. Larger ID is quoted to the nozzle on the pot. Conductive lining is required so static does not spark in dusty work.