Polyurethane Foam: What You Need to Know for Case Inserts

When you're protecting delicate gear like electronics, tools, or instruments, the case only gets you part of the way. It's the foam inside that keeps everything secure and protected from damage.

Polyurethane foam is a go-to choice for case inserts because it offers a good mix of cushioning, flexibility, and affordability. Whether you need something custom-cut or need to keep your gear from bouncing around, it gets the job done.

Need a custom foam insert? Get a quote from our in-house Canadian team.

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Table Of Contents:

  1. What Is Polyurethane Foam?
  2. Why Polyurethane Foam Is Used in Case Inserts
  3. Flat vs. Egg Crate: Which Polyurethane Foam Is Best?
  4. Applications of Polyurethane Foam
  5. How to Choose the Right Foam Insert
  6. How Long Does Polyurethane Foam Last?
  7. Get A Custom Polyurethane Foam Insert

What Is Polyurethane Foam?

Polyurethane foam (also known as PU foam) is a soft, open-cell material made by mixing polyols and isocyanates. It’s light, cushiony, and easy to work with, which is why it’s often used inside cases.

There are two main types:

  • Open-cell structure foam: Softer, breathable, and great at absorbing shocks, working as an anti-static foam.

  • Closed-cell structure foam: Denser and better at resisting moisture (though rarely found in standard polyurethane)    

How It’s Made

The foam forms through a chemical reaction that expands into a sponge-like structure. The process can be adjusted to create different densities depending on how firm or soft you need the foam to be.

Physical Properties and Densities

  • Soft and flexible

  • Absorbs impact well

  • Comes in a variety of densities

  • Not waterproof, but does provide water resistance

  • Easy to shape, cut, or machine

Why Polyurethane Foam Is Used in Case Inserts

Polyurethane foam is popular for case inserts because it checks a lot of boxes:

  • Good shock absorption: Helps cushion gear from drops and vibrations

  • Lightweight: Easy to carry, won’t add much bulk

  • Customizable: Cuts cleanly for custom inserts

  • Budget-friendly: Great protection without overspending

  • Works well for delicate items: Especially useful for electronics and lighter tools

It’s not the right choice for every case, but it meets most everyday needs very well.

Flat vs. Egg Crate: Which Polyurethane Foam Is Best?

The polyurethane foam used in cases typically comes in two shapes: flat and convoluted (often called “egg crate” foam). Each has its own job.

Flat Foam

  • Best for custom-cut inserts

  • Gives a clean, fitted look

  • Supports oddly shaped or heavier items

  • Usually used in the base of the case

Egg Crate Foam

  • Great for case lids

  • Spreads pressure evenly to keep items snug

  • Adapts to a range of shapes

  • Useful when you’re not cutting inserts

Quick Comparison

 

Flat Foam

Egg Crate Foam

Best Use

Precision-cut inserts

Lid padding

Looks

Smooth and clean

Wavy, contoured

Custom Cuts

Easy to cut to shape

Meant to stay as-is

Support

High

Medium

Typical Placement

Bottom of the case

Lid or top layer

 

Common Uses

  • Flat foam: custom gear layouts, tools, instruments

  • Egg crate foam: lid padding, general-purpose cushioning

Applications of Polyurethane Foam

You’ll find polyurethane foam inserts in all kinds of cases. Some of the most common uses include:

  • Electronics (cameras, drones, laptops)

  • Tools and repair kits

  • Medical equipment

  • Musical gear

  • Audio/visual setups

  • Military or tactical gear

It’s ideal when you need lightweight protection for gear that’s not overly heavy.

How to Choose the Right Foam Insert

When picking the foam type for your case, think about:

  • Fragility: The more delicate your gear, the softer and more fitted the foam should be

  • Weight: Polyurethane is better for light to medium items; for heavier gear, polyethylene might be a better fit

  • Case size and shape: Deeper or unusual cases may need layering

  • Custom vs. pre-cut: Custom inserts give better protection and organization

  • Extra options:

    • Adhesive backing

    • Layered inserts

    • Mix of flat and egg crate

If you’re unsure, our design team can help figure out what fits best. Reach out for a custom quote.

How Long Does Polyurethane Foam Last?

Polyurethane foam products typically last 5 to 10 years, depending on their use and storage conditions. Polyurethane foam won’t last forever, but with the proper care, it can stay in good shape for a long time.

What Shortens Its Lifespan

  • Sunlight: UV can cause yellowing and breakdown

  • Weight: Constant compression can leave dents that don’t bounce back

  • Humidity and heat: These can speed up wear

How to Make It Last Longer

  • Keep your cases in dry, cool storage

  • Don’t overload or press sharp items directly into the foam

  • Use lid foam to help spread out pressure

  • Replace the foam if it starts to crack, compress, or fall apart

Get A Custom Polyurethane Foam Insert

Polyurethane foam is a flexible, lightweight, and cost-effective option for protecting delicate gear. It’s easy to work with and holds up well when matched to the right application. 

Need help choosing the right foam? Get a quote for a custom insert made in our Ottawa facility.

Contact Us Today! Give Us A Call

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