Must the gasket come out to be measured?

Answer: Yes. In the groove you measure compressed height, which hides permanent set.

Should an empty case be stored with the latches closed?

Answer: No. Half-latch it with a 2 mm gap so the gasket can recover.

Can ethanol be used on a Prop Charge Container?

Answer: On oil spots, then dry at once. Never let it pool in the groove.

How long should records be kept?

Answer: A year past retirement at least; decay trends need three years of readings.

How Often Should a Prop Charge Container Be Inspected?

Q: How often should a Prop Charge Container be inspected?

Answer: Twelve months for twice-a-month access, 180 days weekly, 90 days on a vehicle.

Q: When is a case scrapped instead of repaired?

Answer: A crack through a rib root, a rim warped past 2 mm, or three repairs.

Quick answer: Set the interval by duty, not calendar: twelve months for a store case opened twice a month, 180 days for weekly access, 90 days on a vehicle. A gasket past thirty percent set or a latch under 120 N is at the line.

Setting the Cycle by Duty
Six Points on Every Walk-Through
Cleaning and Drying
Replacement Lines for Four Parts
Three Things That Add Years
Records: Card, Trace Code, Handover
FAQ

1. Setting the Cycle by Duty

Calendar-driven inspection is a guess. A Prop Charge Container opened twice a year and one opened daily do not age alike.

Duty	Interval	Tier adds
Dry store, under 2 a month	12 months	Shell, gasket rebound, latch travel
Dry store, weekly	180 days	Decay, hinge pin play
Vehicle or yard	90 days	UV, corrosion, markings

One exception overrides the table: after any drop, impact or long soak, run a full check.

Vehicle-tier cases fail first in the wet season: a fortnight above eighty-five percent humidity leaves an unseen film in the groove, and decay climbs from 0.6 to 1.9 kPa.

2. Six Points on Every Walk-Through

Six points, ordered by wear rate: gasket, latches, hinge pins, corners, valve, markings. The first two cause seventy percent of failures.

Prop Charge Container: olive green case upright on a timber bench, handle raised, one latch each side, vertical ribs and neat edge trim, blurred field

Gasket: measure section height once pulled, replace past 30 percent set;
Latches: gauge the closed latch, adjust or replace below 120 N;
Hinge pins: past 0.3 mm of play, replace pin and boss;
Corners: raking light for whitening, retire past 8 mm cracks;
Valve: the plunger should snap back cleanly;
Markings: re-label past a third of lost area.

3. Cleaning and Drying

Cleaning removes salt, dust and oil, not a polish. Polyolefin shrugs off acids but not every solvent, and one wrong wipe cannot be undone.

Soil	Allowed	Never
Dust	Neutral detergent, pH 6 to 8	Solvent cleaners
Oil	Ethanol spot wipe, dry at once	Immersion
Salt	Warm water, 2 hours at 40 C	Heat gun held close
Mould	Diluted wash, lid open	Pressure washer in groove

Never spray into the groove: water drives soil to the bottom and pushes the gasket out of position, so it refits without compression.

Drying is skipped most often. Two hours at 40 C empties the groove and rib cavities; air drying at eighty-five percent humidity does almost nothing.

4. Replacement Lines for Four Parts

Write the call into the sheet; hand-feel drifts between people and a number does not.

A gasket goes at thirty percent set, at any through-crack, or when decay returns above 1.2 kPa. Latches go when clamp force stays under 120 N after adjustment. Pins go at 0.3 mm of play, and the case stays. The body is retired only for a crack through a rib root, a rim warped past 2 mm, or three repairs. Prices differ widely: gasket four percent of case cost, latch seven, pin under two. Explicit lines take a fleet from six years to ten on cheap parts changed on time.

Prop Charge Container: closed olive green case in a timber shed, side latch and folding handle out, scuffs on the lid, sandbag beside

5. Three Things That Add Years

Posture beats material on a Prop Charge Container. Store upright, 100 mm off the floor on a pallet, so water drains from the rib channels; flat storage loads the lid for months.

Four high is the ceiling; past that the bottom rim creeps in and the lid stops seating within a year.

UV chalks the surface, and the chalk wipes off the rib roots with a little wall thickness each season.

A stored case left clamped keeps its gasket loaded; half-latch it with a 2 mm gap.

6. Records: Card, Trace Code, Handover

A box card answers three questions: last visit, parts replaced, next due.

Six columns: case number, in-service date, inspection date, parts replaced, decay reading, inspector.

Etch the trace code into a rib, not the panel, where a score line starts a crack.

Conclusion

Maintenance of a Prop Charge Container is not difficult; the discipline is writing the intervals and limits down. Three tiers, six check points and four replacement lines cover most decisions, and a fleet then lasts a decade on cheap parts changed on time rather than a bigger budget for a Prop Charge Container.

This article discusses only the container (case body) side of specifications and design intent, and does not cover any handling, loading or use of the contents.