Considerations for aluminum heat shrinking
Aluminum is more prevalent than ever on today’s vehicles. What can you do when an aluminum dent has stretched during the repair process?
For example, it is not uncommon for steel panels stretch and therefore require shrinking. However, this issue is usually corrected using heat-shrinking methods for the impacted steel panels. Similarly, aluminum is susceptible to stretching—but is it possible to heat-shrink aluminum? The short answer is yes.
While Aluminum dissipates heat much more effectively than steel, this becomes a problem when we need to shrink a specific area of a panel. To shrink steel, the area is heated using various methods, and once the desired temperature is reached, the area is rapidly cooled using water or cool air.
In the case of aluminum, an induction heater is the desired tool for shrinking. Induction heaters designed for aluminum panels can heat a specific area of the panel much quicker than a heat gun. While the heat gun is used for general aluminum panel straightening, it is not as effective to use during the shrinking process.
Aluminum repairs take more care and precision than steel repairs; the same goes for heat-shrinking aluminum. The amount of heat needed to shrink the aluminum panel is much lower than steel. Generally, the target temperature during the repair is around 250-450°F, depending on the damage.
Around 400°F, the adhesive starts to break down. Adhesive near the area you are shrinking can be a factor in the repair vs. replace decision. When shrinking aluminum, closely monitor the heated area and keep the temperature below 400°F. Exceeding 400°F can cause irreversible damage to the panel.
Aluminum is permanently softened, or annealed, at around 750°F. The panel must not exceed that temperature if it is to be repaired. Take your time, check the temperature often, practice, and carefully observe the progress.
Always follow original equipment manufacturer (OEM) procedures and guidelines for repairability of aluminum panels to ensure a complete, safe, and quality repair.
To learn more about aluminum heat shrinking, visit the I-CAR Canada course catalogue.