No surprises: Pro tips for handling 4:1 Pebax or Polyolefin Heat Shrink Tubing

Image 6.png

When you first order a sample of our 4:1 Pebax® or Polyolefin Heat Shrink Tubing, you might be surprised when it arrives individually wrapped and completely flat. No, the FedEx truck didn’t run over your sample—it’s just that the walls are incredibly thin.

4:1 tubing is completely different from other heat shrink tubing. It’s much thinner—more like household plastic wrap than a plastic straw.

The tubing sample arrives in about a 12" length with an unexpected feature—a “neck” on each end. Here’s our first tip: Don’t cut them off! Here’s what to do. Leaving the neck as is, cut length of tubing you need, plus a little extra to allow for some shrinkage.

To inflate the tubing, simply slide the neck onto the EFD tip attached to the nozzle of your hot box or air hose and add room-temperature air. Next, slide your component into the inflated tube and apply heat using a hotbox or heat gun. Then, do the same for the other piece of tubing. If you're using the whole piece at once, cut off one neck, inflate the tubing, and insert your component before applying heat.

Getting the right size of tubing is essential. We advise customers to order an ID size just a little larger than the max OD of their substrate. With 4:1 tubing, it’s more important to pay attention to the expanded ID number rather than the recovered ID number. Ordering a size close to your max OD also will ensure the thinnest possible wall since the wall thickness increases as it recovers.

A final note on applying heat: Check the recommended temperatures for Pebax or Polyolefin, and don't overdo it! The tubing is so thin that you’ll see it react when you apply heat correctly.

Why use 4:1 heat shrink tubing? Usually, it’s because the customer needs the tubing walls to be as thin as possible (< 1 mil). Common applications include:

  • Outer layer for catheter shaft

  • Cover for coils and braids

  • Jacket for laser-cut hypotube

  • Coating for tapered guidewire

We’re always happy to help if you have a question about your 4:1 tubing sample or want to discuss whether 4:1 tubing is the right choice for your project. Contact us at sales@cobaltpolymers.com or (800) 337-0901.

Sales Foley