Auto Body Filler Hardener Mixing Ratios: The Ultimate Industry-Insider Guide

Jul 11, 2023

Not sure what ratio of body filler hardener to use? Don’t fret: The Autobody Source has a definite report featuring an industry insider!

When it comes to body filler hardeners, there’s no consensus on the proper amount and application. The Autobody Source seeks to settle the debate with its new report.

As summertime heat poses challenges for body filler applications, this resource provides you with valuable insights and recommendations from industry experts. You can learn the proper techniques that can optimize your operations.

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In a recent video clip featuring Evercoat Optex, The Autobody Source generated significant interest and discussion surrounding the best hardener mixing ratio. Seeking expert advice, it turned to Tim McKinney, a representative from Evercoat, for his expertise on the matter.

McKinney emphasizes that insufficient catalyzation can lead to post-curing and repair mapping issues. To address this, Evercoat has implemented stickers on their cans to guide you in achieving the proper ratio.

If you’re working in high-heat conditions, he suggests keeping both the product and the hardener at cooler temperatures. This helps slow down the reaction, reducing the urgency to apply the material quickly and giving you enough time for proper application techniques. Additionally, he suggests spreading the product out over the mixing surface to dissipate heat effectively.

For particularly challenging situations, you should incorporate a small amount of Rage Ultra XTRA #100144 filler. This not only slows down the reaction but also thickens the product, counteracting the thinning effect caused by high heat. Its corrosion resistance, which meets the ASTM B117 Corrosion Test, also offers added protection to car surfaces.

To assist you in achieving optimal results, The Autobody Source provides visual examples of the best-practice mixing ratios for Rage Optex, along with a detailed application guide in the accompanying video.

A spokesperson says: “The strong response to our video is an indication that collision repair professionals have lots of questions with regard to proper body filler hardener application. This new guide, created in collaboration with Evercoat, should give you all the information you need.”


The Autobody Source is a leading online publication dedicated to providing valuable insights, industry news, and resources to professionals in the collision repair industry. With a focus on innovation and best practices, the company serves as a trusted source of information for technicians, shop owners, and industry enthusiasts alike.

Don’t play a guessing game when it comes to vehicle coating products. Read The Autobody Source’s new report so you can master the application of body fillers!

You may visit to read the full report.

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