Why We Foam: How Redline Supercharges Rotomolded Parts
Brought to you by Redline Plastics—where badass manufacturing meets smart engineering.

Let’s talk foam—not just the sticky kind, but the kind that transforms rotomolded parts from good to great.

At Redline, foam isn’t just a filler—it’s a functional part of the design. We use it strategically to add insulation, increase strength, control vibration, and fill voids in hollow rotomolded components. Why? Because rotomolding creates durable, hollow plastic parts—but sometimes, the job demands even more.

Foam is how we deliver that more.

Why Add Foam to Rotomolded Parts?

Rotational molding is ideal for making tough, seamless plastic parts—but those parts are typically hollow. Foam allows us to:

  • Boost structural strength
  • Add thermal insulation and sound dampening
  • Control vibration in high-impact or high-motion uses
  • Fill internal voids for added durability and rigidity

Whether it’s a UTV part, a marine component, or an industrial product, foam helps us make it tougher, quieter, and longer-lasting.

How We Use It: Spray-In Foam for Function

Our go-to? Spray-in polyurethane foam—applied directly into the interior of hollow rotomolded parts. It expands to fit the shape, cures in place, and does its job without adding unnecessary weight.

You get:

  • Thermal insulation for heat-sensitive environments
  • Sound dampening for quieter rides or equipment
  • Added strength where structure matters
  • Less vibration and rattle in motion-heavy applications
  • Seamless void filling in large or complex shapes

Getting It to Stick (and Stay)

Rotomolded plastics like polyethylene and polypropylene are famously hard to bond—so we don’t leave adhesion to chance.

We prep surfaces with tools like:

  • Plasma & Ozone Treatment – These clean, non-contact methods boost surface energy, helping foam chemically bond to low-energy plastics. Great for high-volume runs and complex shapes.

  • A Little Dark Magic – Okay, not actual sorcery—but with the right prep, timing, and materials, our foam adhesion feels a little supernatural.

Our engineers combine science, strategy, and just the right touch of wizardry to make sure your foam stays exactly where it should—for the long haul.

Engineered In, Not Added On

At Redline, foam isn’t a last-minute fix—it’s part of the design process from day one. We tailor everything:

  • Foam type
  • Application method
  • Surface prep strategy
  • Thickness and placement

Because better performance starts with smarter design.

Let’s Build Better with Foam

Foam enhances what rotomolding starts. And Redline delivers both—under one roof, with the expertise to back it up.

Got a product that could benefit from insulation, strength, or quiet confidence?

At Redline Plastics our dedicated team of ninjas is ready to provide you a unique solution to your foam problems pulling from a vast arsenal of kick ass experience that can be tailored to your specific application.  If you’re having problems or need a solution and want to understand which of those applications may best suit you, pick up the phone NOW and give us a call!