Ethafoam STPE200 packaging foam is available from All Foam in thicknesses from 5mm to 100mm, but the thickest option is not automatically the safest choice. The right depth depends on the item, how its weight is spread, the space inside the box or case and what the pack is expected to experience in transit.
Ethafoam STPE200 is a semi-rigid, non-cross-linked expanded polyethylene packaging foam. All Foam keeps it in the dedicated semi-rigid packaging range rather than grouping it with AFP30, AFP45, Plastazote and EPDM on the Closed Cell Foam Sheets page.
What Ethafoam thicknesses does All Foam supply?
The current online range includes 5mm, 10mm, 12mm, 15mm, 20mm, 25mm, 30mm, 40mm, 50mm and 100mm. Sheets are available in 100cm x 120cm and 200cm x 120cm sizes, with white and grey colour options.
A 5mm separator and a 100mm support block solve very different packaging problems, so thickness should be chosen after the pack has been planned.
Why there is no universal Ethafoam thickness
Protective packaging works as a complete system. Two products with the same weight can need different cushioning because their shape and contact area differ. A broad flat base spreads the load across more foam, while narrow feet or corners concentrate it into a smaller area.
Fragility matters too. A solid component may tolerate movement differently from an instrument with protruding controls. The journey also changes the requirement. A product stored on a shelf faces different risks from equipment travelling repeatedly in a service case or crate.
That is why All Foam does not give a simple weight-to-thickness rule for STPE200.
Start with usable internal dimensions
Measure the space inside the actual case, crate or box before choosing foam depth. External dimensions can be misleading because hinges, wheel housings, catches, moulded ribs and rounded corners reduce usable space.
Check:
- internal length, width and depth
- lid clearance
- hinges, ribs and fittings
- the item at its widest and highest points
- handles, feet, connectors and controls
Subtract the item dimensions from the usable internal space. The remaining room has to accommodate base, side, end and lid protection without squeezing the product.
Check weight and contact area together
Weight alone is not enough. An item resting on four narrow feet places more concentrated pressure into the foam than an item of the same weight sitting on a broad base.
Identify which surfaces can safely carry the load and which areas need clearance. Displays, switches, connectors, decorative edges and fragile corners should not automatically be used as support points.
For medium and heavy items, this is especially important. STPE200 is used for transit pads, separators, crate lining and industrial cushioning, but the layout still has to suit the load.
Plan every protective layer
A common mistake is to focus only on the foam beneath the product. A complete pack may need protection on the base, sides, ends, lid and vulnerable corners.
If the item sits on a deep base but can slide into a hard side wall, the pack is incomplete. A thick lid pad can also be unhelpful if it puts constant pressure onto a fragile control panel.
Different sides of the same product can therefore need different foam depths.
When thinner Ethafoam can make sense
Thinner STPE200 can suit applications such as:
- separation layers between compatible products
- planned gap filling
- protective barriers against hard surfaces
- crate lining where only limited movement must be controlled
- layered packs where other materials provide additional protection
A thin sheet should not automatically be treated as a heavy-impact cushion. Its suitability depends on load, available compression and the rest of the packaging.
When deeper Ethafoam deserves consideration
Greater depth can be useful where the pack needs more cushioning travel or a substantial support block, provided there is enough room for controlled compression.
Examples include medium or heavy equipment, crate bases, reusable transit packs and products surrounded by hard structural walls.
Depth cannot compensate for a poor layout. A thick block under a narrow metal foot can still be highly loaded. A deep pad that is permanently squeezed by an over-tight case may not work as intended.
The high load bearing packaging foam guide explains why load distribution matters as much as material depth.
What the STPE200 compression data tells you
The current All Foam technical information lists STPE200 at a nominal density of 24 kg/m3, with compression strength values of 0.024 N/mm2 at 25%, 0.081 N/mm2 at 50% and 0.200 N/mm2 at 70% compression under the stated test method.
Those figures help compare material behaviour, but they are not a universal chart for matching one product weight to one foam thickness. Packaging performance also depends on loaded area, impact conditions, geometry and support layout.
For commercial or engineered packs, use an appropriate documented design and testing process where required.
Think about movement as well as impact
Good packaging should control unwanted movement before the item gains speed inside the container. Check whether the product can slide, lift, rotate, strike the lid or move into a hinge or catch.
The base may need greater depth while the lid only needs enough contact to prevent upward movement. Using the same thickness on every side is convenient, but it is not a design rule.
Always check that the case closes normally without excessive force.
Reusable packaging needs an extra check
A reusable service case or industrial transit pack has different priorities from a one-way carton. Repeated loading and unloading can wear narrow foam walls and expose edges to frequent handling.
Consider how often the item will be removed, whether users will pull on the foam, how the case is carried and whether the material will face moisture, dirt or temperature changes.
The current STPE200 data lists a working temperature range of -30C to +80C and water absorption of 1.19% by volume after 24 hours. Those are material values, not proof that every finished pack is suitable for every environment.
Is 25mm Ethafoam enough?
It can be for some jobs, but there is no responsible answer without knowing the product and pack. The same applies to 10mm, 50mm or 100mm.
Before choosing, check:
1. item weight 2. contact area 3. fragility 4. available internal space 5. likely impacts and vibration 6. movement that must be controlled 7. whether the pack is single-use or reusable
Without those details, thickness selection is guesswork.
Ethafoam thickness for crates and transport cases
In crates and hard cases, Ethafoam can be used as base pads, side pads, end blocks, separators, gap fillers and protective barriers.
Measure the case internally and mark which product surfaces can safely carry load. Keep clearance around switches, displays and delicate protrusions.
If the project needs finished pieces rather than full sheets, read the Ethafoam cut-to-size guide before preparing your dimensions.
Can Ethafoam be layered?
It can form part of a layered packaging arrangement, but layers should have a clear purpose. Multiple pieces can create seams or uneven support if they are poorly positioned.
For repeat commercial packs, a single converted block or purpose-cut component may be cleaner and easier to reproduce. Contact All Foam for non-standard cut-to-size or bespoke converting requirements.
White or grey Ethafoam
All Foam offers STPE200 in white or grey. Colour should not replace specification. Choose the material and thickness from the packaging requirement first, then select the available colour that suits the project.
If a broad colour range and presentation finish are central to the job, Plastazote foam sheets are a separate material worth comparing.
Common Ethafoam thickness mistakes
- Choosing the thickest sheet without measuring the case.
- Choosing by weight without checking contact area.
- Forgetting side and end protection.
- Pressing lid foam onto fragile controls.
- Treating a thin separator as heavy-impact cushioning.
- Assuming one thickness must be used everywhere.
- Ignoring repeated handling in reusable packaging.
- Assuming ordinary STPE200 provides anti-static protection for electronics.
- Treating Ethafoam as interchangeable with AFP30, AFP45 or Plastazote.
Quick answers about Ethafoam thickness
What Ethafoam thicknesses can I buy from All Foam?
The current online range runs from 5mm to 100mm, including 5, 10, 12, 15, 20, 25, 30, 40, 50 and 100mm options.
What is the best Ethafoam thickness for a heavy item?
There is no single best depth based only on weight. Check the contact area, fragility, available case space, expected impacts and how the load is supported.
Is thicker Ethafoam always safer?
No. Foam that is too thick for the available space can put constant pressure on the product or stop the case closing correctly.
Can I use different Ethafoam thicknesses in one case?
Yes, where different base, side, end or lid protection is needed. Each layer should have enough space to work without over-compressing the product.
Is Ethafoam suitable for electronics?
STPE200 can provide physical cushioning, but it should not be assumed to provide a required anti-static or ESD specification. For static-sensitive electronics, compare the dedicated anti-static packaging foam and confirm the exact requirement.
Choosing STPE200 with confidence
The best Ethafoam thickness is the one that gives controlled support and cushioning inside the actual container without leaving harmful movement or creating excessive pressure.
Start with accurate measurements, load distribution and the journey. If the pack is valuable, repeat-use, high-load or technically critical, send All Foam the finished dimensions, item weight, quantity and intended use before ordering.
