Can an explosive storage case be rotomoulded?

Answer: It can, but rotomoulding rarely goes below 5 mm, doubling weight and ruling out one-handed carrying.

Does a dissipative shell drift over time?

Answer: Surface resistance can shift an order of magnitude in a dry season; retest every three years.

Is a single-layer liner enough for one of these cases?

Answer: Only for items of consistent shape. Where shapes vary, a flat pad cannot stop lateral movement.

Are two latches sufficient?

Answer: Yes, if both sit on reinforcing pads and the lock hole is independent; one lock cannot open the case alone.

Does a closed lid flatten the seal?

Answer: It deforms slowly; store with latches released so the cord recovers.

Explosive Storage Case Structure and Craft: 5 Key Points

Quick answer: Five measurable details decide an explosive storage case: a 3.2 mm wall with ribs at 85 mm pitch, a seal groove sharing the rim with a ground post, a retardant load capped by drop results, and four end-of-line readings.

How Wall Thickness and Ribs Are Set
Seal Groove and Ground Post on One Rim
How Much Flame Retardant Before Drop Strength Falls
Latch Lock Boss and Foam Compartments
Four Readings Before the Case Ships
FAQ

1. How Wall Thickness and Ribs Are Set

An explosive storage case is carried by one person or a small team, so volume sits between 8 and 20 litres and the body is single-shot polypropylene moulded. With no rotomoulded wall for stacking load, every throw in a vehicle lands on 3 mm of plastic.

The wall is 3.2 mm, the base 4.0 mm, tolerance ±0.3 mm, because bottom corners take the first hit. Ribs run at 85 mm pitch, 6 mm high, R1.5 root, filling evenly on an 800-tonne press at 40 degrees Celsius; closer ribs sink, wider ones bulge. The lid carries two recesses as stack stops, two cases maximum, not a flat load platform.

Feature	Dimension	What it controls
Body wall	3.2 mm, ±0.3	Crush resistance, boss strength
Base	4.0 mm	First contact on a drop
Rib pitch and height	85 mm and 6 mm	Side wall bulge
Lid depth and corner	45 mm and R20	Opening clearance, corner cracks

2. Seal Groove and Ground Post on One Rim

The rim of an explosive storage case is fifteen millimetres wide: the seal groove takes half, the ground post needs a footprint.

Explosive storage case: four beige cases on concrete, one open with black foam compartments, one closed under two latches, one on a pallet

The seal is 5 mm EPDM cord in a 6.2 mm groove, compressed 22 percent, floor flat to 0.3 mm. Below 18 percent it leaks; above 28 percent the lid must be forced and latches wear first.

Static control runs on material and grounding. The shell is dissipative grade at 10 to the 6th to 10 to the 9th ohm; an M6 nickel-plated brass post sits in the boss inside the handle mount, only a nut showing outside. Grind the paint off before measuring and hold 10 ohm or less. The case is opened by hand, so discharge starts at the handle; handle mount and ground post must form one path.

3. How Much Flame Retardant Before Drop Strength Falls

Retardancy and toughness pull against each other on a thin wall: the same 6 percent masterbatch costs a 3.2 mm wall more impact than an 8 mm box wall, since a thin section is mostly oriented skin.

Three numbers fix the claim: glow-wire ignition at 750 degrees Celsius or higher, UL94 V-0 on a 1.6 mm bar, afterflame of 8 seconds or less. The masterbatch works from 5 to 6 percent, and notched impact falls from 11 to 8 kilojoules per square metre; 0.4 mm more base and 0.8 mm at rib roots recovers about 9.5. Past 9 percent, corners crack on a cold drop test.

4. Latch Lock Boss and Foam Compartments

Closure is two latches plus one central lock hole. Latches are rated 380 N pull, the hole is 7 mm through, and the boss needs 3 mm of wall or one pry opens the shell.

Explosive storage case: a grey corner in a workshop, one latch clamped on the rim, folding handle at right, pallet behind

The liner is EPE at 25 kilograms per cubic metre in six compartments, 8 mm walls, under 1 mm clearance, top 3 mm below the seal groove. Flush or proud, and the lid presses foam before seal, killing air tightness. The real argument is opening force: thicker liner, forced lid, preload, fatigued boss. Trim foam rather than uprating the latch.

5. Four Readings Before the Case Ships

Four readings tell whether a batch is stable: air tightness, opening force, drop, surface resistance.

Air tightness is charged to minus 20 kilopascals for 60 seconds, decay 0.5 or less; IP67 takes one metre of water for 30 minutes.

Reading	Limit	Instrument
Air tightness	Minus 20 kPa held 60 s, decay 0.5 kPa	Leak tester
Opening force	60 N or less per latch	Push-pull gauge
Drop	1.2 m, six faces, rated ballast	Drop rig
Surface resistance	10 to the 6th to 10 to the 9th ohm	Resistance meter

Three units per batch go through the drop; hardware takes 24 hour neutral salt spray. A drift means checking the mould and resin lot first.

Conclusion

Wall and ribs decide the drop, groove and post must agree on fifteen millimetres of rim, retardant load is set backwards from drop results, clearances set the feel, and four readings tie the rest together. In an acceptance sheet, those five are what a well-built explosive storage case sells.

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.