Walk into any hardware store in Germany, Austria or the Netherlands and you will find a wall of aluminium cases: silver, ribbed, with a foam grid inside and a price that makes them hard to argue with. Search for "Alukoffer" or "aluminium case" and you will find tens of thousands of people every month looking for exactly that. Then a colleague turns up with a black Peli case, and the questions start. Is it really better? Better at what? And why does it cost more? ⚖️
We sell Peli cases, so you know where our interest lies. We also spent fifteen years watching customers arrive with aluminium cases that had let them down, and a few who arrived with aluminium cases that were exactly right for the job. This guide is the honest version: nine differences that actually change the outcome, the four situations where aluminium is the smarter buy, and a method for choosing that does not depend on brand loyalty.
One definition before we start. "Aluminium case" here means the common briefcase-style and tool-style cases with an aluminium frame and either aluminium or ABS panels, sold under dozens of brands. Not the heavy-duty machined aluminium enclosures used in aerospace, which are a different product at a different price.
Part 1: Nine differences nobody explains before you buy
1. What "aluminium" actually means on the label
Most aluminium cases are not aluminium boxes. They are an aluminium frame with thin panels riveted or clipped into it. The panels are often ABS plastic with a brushed-metal finish, or aluminium sheet between 0.5 and 1 mm thick. The frame gives the case its shape; the panels give it its look. The corners are separate castings or stampings, attached with rivets.
A Peli Protector case is a single moulded shell of polypropylene copolymer, several millimetres thick, with the ribs, feet, handle mounts and latch anchors formed in the same piece. There is no frame, no panel and no rivet. The lid is a second moulding that closes on an O-ring seated in a channel. That is the entire difference in construction, and it explains most of what follows.
2. Dents, cracks and what happens after a drop
Drop an aluminium case and the metal does what metal does: it dents. A dent in a panel is cosmetic. A dent in the frame near a hinge or a latch means the lid no longer closes true, and the case is finished as a protective container even if it still carries things. Thin aluminium also cracks at rivet holes after enough vibration, which is why old aluminium cases rattle.
Drop a Peli case and the polymer flexes, absorbs the energy and returns to shape. The ribbed corners are the thickest part of the moulding for exactly this reason. Peli tests Protector cases for drops at full load, in the cold, on the corners, and the lifetime guarantee covers breakage of the shell. A polymer case can be scratched, scuffed and worn; it is very hard to make one stop closing.
3. Water: the difference between a gasket and a seal 💧
Some aluminium cases have a rubber strip around the lid, and marketing calls this "waterproof" or "splash-proof". It is neither in any tested sense. The strip sits on a frame with dozens of joints, the latches do not compress it evenly, and the corners are where the rivets are. Rain on the lid runs off; rain on the side finds a seam.
Peli Protector, Storm and Air cases are rated IP67: closed, they survive submersion to one metre for thirty minutes, and dust cannot enter. The seal works because the shell is continuous, the O-ring sits in a moulded channel, and the latches pull the lid down with even pressure all round. We explained what IP67 does and does not promise in waterproof, water-resistant or submersible. For kit that lives in a van, a boat, a site cabin or a rucksack in the rain, this is usually the deciding difference.
4. Weight, and why the numbers surprise people
Aluminium has a reputation for lightness because it is lighter than steel. It is not lighter than polypropylene at the thicknesses used in cases, and the frame-and-panel construction adds hardware everywhere. A typical mid-size aluminium tool case weighs 4 to 6 kg empty. The Peli 1500, a similar footprint, weighs about 3 kg. The Peli Air 1525, again a similar footprint, weighs under 2.5 kg. The difference grows with size: a large aluminium case with wheels can weigh 12 kg before you put anything in it.
Weight matters twice. Once for whoever carries the case, and once for checked-baggage and courier limits, where every kilo of case is a kilo of equipment you cannot take.
5. Pressure and altitude
Aluminium cases are not sealed, so pressure is never a problem for them. The moment you make a case sealed, it becomes one: fly with a sealed case and the pressure difference can lock the lid shut or bulge it. Peli solves this with an automatic pressure equalisation valve, a small membrane in the shell that lets air molecules through and keeps water out. It is the reason a sealed case can go through a cargo hold, a mountain pass or a hot car and open normally afterwards. Aluminium cases avoid the problem by not being sealed, which is a solution only if you never needed the seal.
6. Temperature: minus 40 to plus 99
Aluminium conducts heat quickly. A case left in the sun becomes an oven inside within minutes, and a case left in a winter van is cold to the touch and cold all through. Condensation forms on the inside of a cold metal case the moment warm air reaches it, which is how optics fog and electronics corrode.
Polypropylene is a poor conductor of heat. A Peli case in the sun warms slowly, and the sealed interior holds a stable microclimate. Peli rates Protector cases for use from -40 to +99 degrees Celsius. The polymer does not become brittle in the cold or soft in the heat within that range, and the O-ring keeps humid air out, so the condensation problem is largely removed. We listed what summer heat does to unprotected kit in 12 everyday items that won't survive summer in your car.
7. The interior is where cheap cases save money
The foam grid inside a typical aluminium case is thin, low-density polyurethane, often glued to the panels. It compresses permanently after a few months, tears at the grid lines, and cannot be replaced because it is glued. The lid foam is frequently a single flat sheet. The result is a case that held the kit perfectly on day one and rattles by month six.
Peli cases ship with a three-layer foam system (convoluted lid foam, pick-and-pluck block, solid base) that is not glued and is sold as a replacement set for most models. Beyond foam, the same case takes padded dividers, TrekPak, lid organisers and CNC-cut inserts, because the interior dimensions are standard and stable across production years. The options are compared in foam, dividers or TrekPak. A case whose interior can be rebuilt is a case that lasts through three generations of equipment.
8. Latches, hinges, handles: what breaks first
On aluminium cases, the failure points are the latches (thin stamped steel, sprung with a small wire), the hinges (a continuous piano hinge or two small ones riveted to thin metal) and the handle (often plastic on a wire bail). When one fails, the case is usually replaced, because spare parts do not exist for unbranded cases and the rivets make repair a workshop job.
On Peli cases, the latches are double-throw polymer with a stainless pin, the hinges are moulded into the shell with stainless pins, and the handles are over-moulded. All of them are user-replaceable, sold as spares, and covered by the guarantee. A latch swap is a five-minute job with a screwdriver. That is the difference between a case that gets thrown away and a case that gets fixed.
9. Cost over ten years, not on day one
An aluminium case is cheaper on the day you buy it. Sometimes by half, sometimes by two thirds. That is a real advantage and we are not going to pretend otherwise. The question is what happens over the working life of the equipment inside.
An aluminium case that is used daily typically lasts two to four years before a latch, hinge or dent retires it. A Peli case used daily is expected to last the life of the equipment, and often the equipment after that; the lifetime guarantee is not a marketing line, it is the reason the cases are still in circulation twenty years later. Over ten years, the aluminium route is two or three cases plus the kit that got damaged in the one that failed. We ran the numbers, and the sceptic's objections, in are Peli cases worth the money?
Protector cases in the sizes people buy aluminium cases for
Part 2: Four situations where the aluminium case is the smarter buy
Presentation and sales samples
An aluminium briefcase opens flat on a client's desk, looks the part, and holds samples, brochures and a tablet in a tidy foam layout. It will never see rain, never be dropped from a tailgate, never fly in a hold. Its weaknesses do not apply, and its price and look are its strengths. For a sales team, this is the right case, and we say so when asked.
Storage that never travels
Coins, small parts, documents, a collection that lives on a shelf and is opened at a desk. The case is a drawer with a handle. Sealing, drop resistance and pressure valves are paid for and never used. Buy the aluminium case, or frankly a good storage box.
Very tight budgets with low-value contents
If the contents are worth less than the difference in case prices and are easy to replace, protection is not the priority. A hobby kit, a set of hand tools from the hardware store, a first-aid kit for a workshop that never leaves the wall. The aluminium case does the job.
Custom sizes for one specific object
Aluminium-frame cases can be built to order in almost any dimension, cheaply, by a local case maker. If you need a case for a single awkward object that fits no standard model, and that object is not fragile, a made-to-measure aluminium case beats trying to force it into the nearest Peli size.
Part 3: The situations where aluminium quietly fails
Cameras and lenses
The combination of thin foam, condensation and a case that does not seal is exactly wrong for optics. Fungus grows in lenses stored in humid, unsealed cases; dust reaches sensors; a dented frame lets the lid gap. Most of the photographers who come to us with a damaged lens had it in an aluminium case. For this use, the sealed polymer case with a proper interior is not a luxury.
Anything that flies as checked baggage
Baggage handlers stack, throw and drop. An aluminium case arrives dented at the corners after the first flight and with a bent frame after the third. Airlines also treat visible damage to a rigid case as a reason to reject a damage claim. Peli cases are the reason people can check expensive equipment at all; we cover the practical side in toughest suitcases for air travel.
Field electronics, radios, drones, test equipment
Vibration on a vehicle floor works rivets loose. Rain and dust get into unsealed cases. Cold metal condenses moisture onto circuit boards. Every failure mode of the aluminium case lands on electronics first. The military and utility sectors standardised on sealed polymer cases decades ago for this reason.
Anything with a lifetime longer than three years
Calibrated instruments, medical kits, survey equipment, firearms. If the kit is going to be in service for a decade, the case should be too. An aluminium case will be replaced at least twice in that time; a Peli case will be repaired, if it needs anything at all.
Part 4: How to choose without brand loyalty
Ask what the case has to survive, not what it has to hold
Write down the worst realistic day for the case: the flight, the rain, the drop from the van, the week in a hot car, the winter in a site cabin. If that list contains water, drops or temperature extremes, the sealed polymer case is the answer. If the worst day is "sits in an office", the aluminium case is fine.
Price the contents, not the case
A 200-euro case protecting 5,000 euros of kit is cheap insurance. A 200-euro case protecting 150 euros of kit is an indulgence. Most buying mistakes in both directions come from pricing the box instead of what goes in it.
Check the interior can be rebuilt
Ask whether replacement foam, dividers or custom inserts exist for the exact model. If the foam is glued in and no spares exist, the case has a fixed lifespan whatever the shell is made of.
Check what happens when a latch breaks
Ask for the part number of a spare latch. If there is no answer, the case is disposable. If there is, and it is a five-minute swap, the case is a long-term purchase.
Match the case to the transport chain
Checked baggage has weight and size limits; couriers charge by volumetric weight; two-person carries need side handles. Peli model numbers encode interior dimensions, which makes this planning much easier; we decoded them in what Peli model numbers actually mean. If weight is the constraint, the Peli Air series gives up nothing on sealing and drop resistance and saves up to 40 percent against Protector, which puts it well under most aluminium cases of the same size.
Peli Air: lighter than the aluminium case, still IP67
Part 5: Six myths that keep the debate going
"Aluminium is stronger than plastic"
Aluminium is stronger than plastic per millimetre of thickness. Cases do not have the same thickness. A 0.8 mm aluminium panel is far weaker in impact than a 4 mm polypropylene shell with moulded ribs. Strength of a material and strength of a product are different questions.
"Plastic cases crack in the cold"
Cheap polystyrene and PVC cases do. Polypropylene copolymer, which is what Peli Protector cases are moulded from, is chosen precisely because it stays tough at -40 degrees. The cold-weather drop test is part of the qualification.
"Aluminium looks more professional"
In a boardroom, perhaps. On a film set, a survey site, an aircraft apron or a military base, the black polymer case is the professional standard and the silver briefcase is the visitor. Context decides.
"The rubber strip makes it waterproof"
A rubber strip on a riveted frame is a draught excluder. Waterproof means a tested rating, and almost no aluminium case has one.
"Peli cases are only for the military"
They are used by the military because the military needed the specification. The same specification suits photographers, engineers, medics, musicians, divers and anyone who checks luggage. The cases do not know who bought them.
"You are paying for the name"
You are paying for the mould, the material thickness, the O-ring, the valve, the stainless hardware, the drop and immersion testing, the spares supply and the guarantee. Remove all of those and you have an aluminium case at an aluminium-case price. That is the honest comparison.
Frequently asked questions
Can I fly with an aluminium case as checked baggage?
Yes, but expect dents after the first trip, and understand that airlines routinely reject damage claims for rigid cases with visible external damage. If you check it, do not put anything fragile inside.
Is a Peli case heavier than an aluminium case of the same size?
Usually lighter. Peli Protector is roughly on par with or lighter than a comparable aluminium case; Peli Air is substantially lighter, typically by 30 to 40 percent.
Do Peli cases conduct heat or cold to the contents?
Far less than metal. Polypropylene is a poor conductor, and the sealed interior slows temperature change further. Contents still equalise eventually, but without the condensation that a cold metal case causes.
What about Storm cases: are they closer to aluminium in price?
Storm cases are a different Peli line with press-and-pull latches and a slightly lighter shell, also IP67, also guaranteed. They sit at a similar price level to Protector; the saving over aluminium is never on the first day, only over the years.
Can an aluminium case be repaired?
Dents can be pushed out; frames rarely straighten; latches and hinges on unbranded cases have no spares. Repair is usually replacement.
Checklist: aluminium or Peli?
- ✅ Rain, dust, immersion or a hot car in the case's future? Peli, sealed IP67.
- ✅ Drops, flights, courier shipments? Peli, moulded shell with lifetime guarantee.
- ✅ Optics or electronics inside? Peli, for the condensation alone.
- ✅ Kit in service for more than three years? Peli, because spares exist.
- ✅ Weight-critical? Peli Air.
- ✅ Office presentation, shelf storage, low-value contents, one-off custom size? Aluminium is fine.
- ✅ Unsure? Price the contents, list the worst day, then decide.
The short version
An aluminium case is a frame with panels, built to a price, and it does an honest job on a desk or a shelf. A Peli case is a sealed moulded shell, built to a specification, and it does its job in the rain, in the hold, on the floor of a van and in a flooded cellar. Buy the aluminium case for the boardroom. Buy the Peli case for everything that leaves it. 🛡️
If you are replacing an aluminium case that failed, tell us what was in it and how it failed. We will point you at the size and series that would not have.
