Heat shrink tape is a critical component in the production environments of multiple industries around the world — ranging from automotive, aerospace, and energy to sporting goods, oil & gas, and many other industrial manufacturing applications.
If you’re manufacturing products in one of these industries, you’re likely using a compaction film of some kind to compress composite materials such as carbon fiber, Kevlar®, or fiberglass, or you might need to apply light compression to vulcanized materials such as rubber, silicone, or PVC for hose, roller or fluid transfer purposes.
While there are a variety of compaction film options available, only Hi-Shrink Tape from Dunstone provides the consistent, reliable compaction needed to produce the desired results while also keeping costs down and increasing overall productivity. This is because it provides compression on a tailored curve as the curing temperature increases, whereas non-shrink films like cellophane, woven nylon, or polypropylene will begin to relax with higher temperatures — putting system integrity at risk and leading to low-quality products with poor performance.
But with a variety of tapes available, what’s the best heat shrink tape for your specific needs? Do you need a solution that functions in extremely high curing temperatures? Perhaps a Hi-Shrink Tape that’s incredibly thin with a lower shrink percentage is ideal. Or, you might need a shrink tape that provides a much higher compressive force to ensure the resin system properly penetrates the layers and spaces in the material.
Here, we’ll explore a few questions to ask in order to understand what the best heat shrink tape is for your respective application. Of course, there may be additional considerations that aren’t explored here. It’s always best to speak with one of our expert engineers regarding your use case and end goals. Connect with them now to get started.
How Much Shrink Force is Needed?
As you explore our portfolio of Hi-Shrink Tapes, you’ll see that there are a wide range of shrink percentage and force figures for different products. The term MD shrink refers to the shrink percentage in the machine direction. Tapes are available with MD shrink percentages ranging from 5% up to 20%. Max shrink force, just as it sounds, refers to the amount of force applied in pounds per inch of width. Our tapes apply anywhere from 1.65 (HT Series) lb. of force up to nearly 22 lb. of force (500 Series).
It’s important to understand that a number of other factors contribute to the overall compressive force being applied to a part. Other elements like tape thickness, taping tension, the number of layers of tape used, overwrapping percentage, and the diameter of the product being wrapped all contribute to the result. If you or your production team are fairly new to this product type, check out our blog on how to use heat shrink tape.
Calculate PSI during tape application: Use our handy calculator to determine how much pressure is being applied by using a specific tape based on your usage details.
How Thick Does the Tape Need to Be?
As mentioned above, tape thickness is a key consideration in identifying the best heat shrink tape. It’s extremely fast and easy to identify the thickness of Dunstone Hi-Shrink Tapes — the first number in the numerical name of a product (e.g. 210S) refers to the thickness in mils. So 210S is 0.002 inches thick, or 0.05 in millimeters. We offer our Hi-Shrink Tapes in 1-, 2-, 3-, and 5-mil thicknesses, with 2-mil tapes being the most common and accessible.
But what thickness is right for your application? Generally, if you have a thin-walled part that’s smaller, you’d use a thinner Hi-Shrink Tape (like the carbon fiber shaft of a golf club). Larger, thicker products, like drive shafts or composite utility poles would require a thicker tape in order to provide the required compressive force. Of course, every application is different, so be sure to discuss yours with our team.
Is a Release Coating Required?
Unlike adhesive-lined tapes, Dunstone Hi-Shrink Tapes don’t require any adhesive in order to be fixed to a part. They can simply be wrapped around and fixed by overlapping the starting end. In most cases, the tapes are simply removed from the part after curing or ground off. In some instances, the tape stays in place — serving as a protective barrier. That said, some resins or materials may require an additional solution for removing the tape. This is where release coatings come into play.
Dunstone offers our Hi-Shrink Tapes with one- or two-sided release coatings. These are indicated in our product part names by an S (standard, no coating) or an R (release coated). After the curing process, a release-coated Hi-Shrink Tape can quickly and easily be removed from the layup, typically without leaving behind any “cello marks” and producing a consistent, clean surface finish. We also have a new release coating available in the 200 Series line that is a zero-transfer UV-cured Silicone coating that can used for demanding release applications where the standard PTFE coating will not work. Contact us for details.
All of our 100, 200, 300, and 500 Series Hi-Shrink Tapes come in standard or release-coated variations. Our HT series is naturally designed to provide excellent release characteristics, and the extremely high-temperature X series also provides some release abilities.
Does the Application Produce Gas or Other Volatiles?
A final — and very important — consideration for your application is what the best heat shrink tape is for resin systems and materials that, when compressed, either produce or could trap various gasses and other volatiles in the matrix. Failing to allow these elements to escape can also result in voids, imperfections, or de-lam (when the layers don’t properly bond). In these instances, a perforated shrink tape is critical to success.
However, many people mistake these perforations as a method for allowing the excess resin to escape the layup during compression. While this can technically happen, most excess resin actually escapes between the tape layers. The perforations are intended for gasses and other volatiles to pass through — resulting in more consistent part appearance and performance while reducing the chance of voids and other negative results post-cure. Two specific Dunstone Hi-Shrink Tapes with perforations include our 220R and 220S series.
Let’s Find the Best Heat Shrink Tape for Your Part Needs
Dunstone has been manufacturing and engineering a full line of Hi-Shrink Tapes for multiple industries for decades. Our expert team is ready to help you find the right product to ensure lasting performance, but why not take some for a spin first? We offer complimentary samples of our readily available tapes — just reach out and let us know what you’re thinking.