Along with its benefits of durability, low-maintenance, and authentic aesthetics, cellular PVC trim offers workability for crafting into a range of styles; heat-bending PVC trim expands the opportunities even more, allowing contractors to elevate both exteriors and interiors.
What Is Heat Bending?
As a thermoplastic polymer, cellular PVC becomes pliable or bendable when exposed to certain temperatures then returns to a solid state upon cooling. As such, some cellular PVC profiles can be reheated and re-formed, or bent into new shapes.
Variations in batches, profile geometry, and profile density or weight will likely require some trialing and or experimentation to perfect this art and skill.
For best results, do not bend any cellular PVC trim that is more than 6″ wide. Some profiles are produced in a special formulation that facilitates bending, however the capability to bend cellular PVC trim is limited—not all pieces can be successfully bent 100% of the time.
Methods for Heat Bending Cellular PVC Profiles
There are several different methods that can be used to heat PVC profiles:
- Heat blankets (great for jobsite fabrications)
- Convection air circulating ovens
- Radiant ovens or heaters
- Heat guns (great for small jobs and profiles)
Temperatures and Dwell Times for Bending Cellular PVC Profiles
Generally, temperatures in the 275°F to 325°F range are used to heat the material.
- Heat soaking at 325°F has been found to be more reliable and predictable when heating and bending profiles with the formulation in Royal Trim, Kleer, and Skytrim. Because this temperature is close to the melt temperature of cellular PVC, bend results will vary depending on profile geometry, thickness and width.
- We have determined that heat soaking at 300°F will require longer soak times to achieve an acceptable bendable product.
- Soak times are dependent upon the width, thickness, geometry and density of the profile. Typically, wider and thicker parts require longer dwell times.
- Some experimentation is needed to find the exact temperature, soak time and bending technique that will yield acceptable results.
- Fabricators need to take care not to overheat the product, as this will produce negative results, such as a rough texture, product deformation and possible discoloration. In addition, heat bending embossed or textured cellular PVC, will cause this surface attribute to fade, distort or disappear. Care must be taken to not distort the surface or cross sectional shape of the profile, and good bending techniques are usually learned and improved through experience.
(Whatever method is used, Royal Building Products assumes no liability, for any harm or damage to persons, product or property related to heat bending. Any and all safety precautions to prevent any harm or hazard should be followed by the end-user.)
Best Practices for Bending PVC Trim
It’s important to note that bending cellular PVC is an art and skill. The ability to bend cellular PVC trim is limited—not all lineals can be post thermoformed with a 100% success rate. Getting the optimal results will require dialing into temperature ranges and dwell times to get an acceptable bend.
In addition:
- For best results, do not bend any PVC cellular trim more than 6 inches in width or below minimum radius of 24 inches.
- Soaking at 325°F has been found to be more reliable and predictable when heating and bending profiles with our formulation. Heat bending cellular PVC should be done carefully and gradually.
- For gradual heat soaking, heat the product at 270°F for 8 to 12 minutes. Then take the product up to ranges of 300°F to 325°F for 5 minutes or less.
- Allow the product to cool after heat bending. Use low volume forced air (industrial fan) to speed up cooling after heat bending.
- Always wear protective gear and work in a well-ventilated area when heat-bending PVC trim.
Want to learn more about heat-bending cellular PVC trim? Contact one of our representatives today.