With Small-Diameter Cylindrical Parts, Precision is Key

Part design influences a number of manufacturing decisions, especially when it comes to the products that are used to support key processes. For companies using composite materials such as carbon fiber in their parts, compaction of the composite material is one of these key processes. Shrink tape for composites is one of the most common solutions, alongside autoclaves and vacuum bagging.

However, when it comes to using shrink tape, part design is a critical detail that cannot be ignored or deprioritized. The diameter of parts, especially those with a small cylindrical structure, significantly influences the type of shrink tape needed. Here, we’ll explore shrink tape for composites through the lens of three small-diameter products from the sporting goods industry: arrow shafts, golf clubs, and fishing rods.

How These Products Are Typically Made

It’s helpful to understand first how golf shafts, arrow shafts, and fishing rods are manufactured. They all follow a similar process that’s tailored to small diameters and overall performance requirements. A carbon fiber prepreg is cut to geometric patterns, then rolled over a mandrel or tool depending on design needs. Once wrapped, machines apply a layer of shrink tape or film to consolidate the layup. The assemblies are then hung vertically in ovens to cure, a process that enables uniform resin flow and surface quality. After curing, the tape or film is removed — sometimes peeled away like a snakeskin, other times stripped by high-speed unwrapping machines — before the shafts undergo sanding, painting, and labeling. With that clarified, let’s dig into the specific products.

1. Arrow Shafts

When it comes to arrow shafts, consistency in compaction is quite possibly the most important outcome of the process. Whether for hunting, elite archery competitions, or even casual use, the consistent compaction of the resin and composite along the arrow shaft makes a difference — particularly when arrows receive frequent use.

Shafts where the compaction process was inconsistent can result in voids, delamination, weight imbalances, flexibility issues, and more. While some of these issues contribute to the accelerated breakdown of the shaft with each use, others will result in instant problems such as unpredictable aiming, inaccurate shots, arrow speed, and more.

2. Golf Club Shafts

Archery and golf are both high-precision sports, and the quality of the composite material and compaction processes will play a significant role in that precision. While compaction is critical with arrow shafts, it’s arguably more critical in golf club shafts because clubs will see dozens of swings (hopefully not hundreds!) during an average game. Any voids, imbalance in the resin flow, dry spots, and under-compaction could result in poor performance, weak feel, over/under-stiffness, and other negative outcomes.

With golf club shafts, precise layup tooling and processes are critical to success. Autoclaves are common here, but mandrels and shrink films are also a regularly used solution. With the latter, extreme precision is needed as the film is wrapped around the length of the part. It’s common to see high levels of over-wrapping and even multiple layers in order to achieve the compaction needed for consistency.

  • The thickness of shrink tapes and films in compaction processes matters in multiple industries beyond sporting goods. Learn more here.

3. Fishing Poles

Fishing rods demand the same level of precision as composite arrow shafts and golf clubs — but for different reasons. In general, fishing rods don’t see the same high impacts as these other shaft types, but the stress on high-end rods can be intense — especially when there’s an aggressive, heavy fish fighting on the end of the line. However, proper compaction is still critical for success.

Voids in composite fishing rods actually reduce sensitivity to important moments, such as detecting micro-bites or vibrations. Poor compaction can also lead to dead spots along the shaft, creating higher risk of delamination, inconsistent bending and recovery, and lower energy transfer when casting.

Other Key Considerations

While established manufacturers may already have autoclaves in place, they are not necessarily required in order to achieve the same level of compaction. Dunstone Hi-Shrink Tape is commonly used in high performance applications where consistent compaction throughout the curing process is essential to successful manufacturing.

The same levels of pressure achieved with an autoclave are also achievable with tape. Of course, this depends on the part geometry and circumference, but whether through machine winding or manual application, Dunstone Hi-Shrink Tape is an outstanding, reliable, and cost-effective solution. Examples of our Hi-Shrink Tape for composites in these applications include:

  • 220R — One of our staples, 220R features a .002” (0.050 mm) thickness, 20 percent shrink, and 8.6 pounds of shrink force. It features a release coating on one side to allow for easy removal from the layup after curing.
  • 212HT — If your application requires higher curing temperatures while also benefiting from release properties and moderate compaction force, 212HT is the way to go. It’s designed for complex shapes and offers higher temperature capabilities for thermoset applications up to 180°C.
  • 500 Series — When you need maximum compaction during cure, as many of these applications do, the Dunstone 500 Series Hi-Shrink Tape is the solution. It provides more than 20 pounds of shrink force, enables extremely high taping tension, and provides a maximum shrink of up to 20%.
  • X Series — If your production process requires extremely high temperatures for curing, the Dunstone X Series Hi-Shrink Tape will bring the heat. It’s designed for applications with cure temperatures of up to 400ºC/752ºF.

Request a Free Sample

Complimentary samples are available for all of our in-stock Hi-Shrink Tapes, including those mentioned above. Simply reach out, and let us know some details about your application. We’ll get a sample sent out right away. If your application is more complex, our engineers are ready to assist. Reach out to us to discuss custom solutions.