Quick answer
For most jobs we recommend foam or polyurethane foam. EVA is a petrochemical product, so it is expensive and its price fluctuates; it can smell, and if swelling after cutting is not allowed for it will not hold the product well. Harder does not mean a better grip.
The insert inside a box is what holds the product in place and protects it in transit. There are many options: board or carton dividers, foam, polyurethane foam, EVA and vacuum-formed trays. The most common mistake with inserts is assuming that a harder material protects better, or that EVA is more premium. In this article we explain which insert we recommend and why, the values we look at when choosing foam, and what to watch for with EVA.
In short
- Board and carton dividers adapt quickly but don't grip in three dimensions; foams grip the product, protect it from impact and stop it moving.
- We use 22-density foam rather than 16, recommend black foam over white, and apply flocking for a premium look.
- EVA is expensive, its price fluctuates and it can smell; we always test its cut against the actual product.
What does each type of insert do?
| Insert | Characteristics | When to use |
|---|---|---|
| Board / carton divider | Paper-based, quick to adapt; made in 1 to 3 layers, no three-dimensional grip | When separating products and holding them in place is enough |
| Vacuum-formed tray | Pressed with a mould | High-volume jobs |
| Foam / polyurethane foam | Grips the product, protects against impact, stops movement | When protection and a neat look are both wanted |
| EVA | Does the same job as the foam group; a petrochemical product | When there's a specific requirement |
Foam, polyurethane foam and EVA are really the same type of product: they all wrap the product, protect it from knocks and stop it moving inside the box. The differences show up in cost, texture and application. Vacuum-formed trays are pressed with a mould, so they depend on volume; on small runs the mould cost dominates.
What do we look at when choosing foam?
Density. The market widely uses 12 to 16 density foam as the economy option. We generally don't use 16 density; our standard is 22-density foam. We can source up to 40 density when the job needs it.
Thickness. We set thickness by the product's size and weight. For round or similarly shaped products, we make sure the foam thickness covers the product's radius. That keeps foam cost at a minimum while still giving full protection.
Colour. We avoid recommending white foam where we can, because by its nature it tends to yellow over time. We recommend black foam.
Finish. For a refined look we flock the foam surface. Flocking comes in different colours, and since it's the top visible surface it fully delivers the premium feel.
We don't need the product to cut foam; we can produce from a technical drawing alone.
What should you watch for with EVA?
EVA is often requested for inserts because it's seen as more premium. In fact both its chemistry and its look make a premium texture harder to achieve. So we don't recommend EVA, but we source and apply it when asked. If you choose EVA, keep these in mind:
- Price. EVA is a petrochemical product, so it's expensive and its price fluctuates.
- Hardness. A harder material doesn't mean a better grip.
- Swelling and expansion allowance. If the swelling and expansion after cutting aren't calculated well, the product won't be held properly or the insert won't sit right in the box. That's why we never cut EVA without the product; we always test against it.
- Odour. The chemicals in EVA can give it a smell, which matters especially for perfume and cosmetics. Ammonia-free or so-called A-grade EVA has no odour, but costs considerably more.
For these reasons we suggest leaning towards foam or polyurethane foam for inserts wherever possible.
For foam types, density and how cutting methods affect cost, see PackPrice's foam insert guide. For the boxes these inserts go into, read our rigid box and magnetic box articles.
Get in touch with your product's size and weight, or see our box models on the products page.