By CRM Staff
Toronto, Ontario — June 6, 2018 — A 16-page research report released October 2017 by the Aluminum Association finds filiform corrosion to be a real issue for aluminum repairs, especially “in wet and salty environments typical of the east coast of Canada or the USA.” Filiform corrosion differs from the galvanic corrosion steel-aluminum contact can produce, and typically doesn’t pose a structural or safety concern, however can generate a visible “‘paint blemish,” which may result in costly comebacks, and a blemish on a shop’s reputation. “(I)t is certainly understandable why the customer would object to such a blemish in a modern vehicle,” the association wrote.
The association notes that sanding can prompt filiform corrosion, which raises additional considerations for OEMs and repairers. “Sanding or abrading the aluminum surface prior to paint has the potential to make the surface more prone to filiform corrosion since the abrasion process effectively thickens the oxide surface which must be removed prior to the pretreatment,” the report states. “For after-market repair where parts have been abraded, particular care must be taken to prepare the surface for paint.”
According to Repairer Driven News study also provides an overview of how corrosion protection works — or doesn’t — in hemmed aluminum surfaces at the factory, which should provide some perspective on what could happen when a collision repairer works on an aluminum hem flange in the shop.
Careful preparation and coating/sealer work is necessary to avoid any comebacks years later, reports the study.
Collaboration between OEMS, aftermarket repairers and other industry stakeholders might be necessary in order to ensure quality safe aluminum repairs.
To read the full Aluminum Association’s Report, please visit drivealuminum.org/wp-content/uploads/2018/03/HoodCorrosionLong.pdf.
