Q: Looking for epoxy that is resistant to DOT 3 brake fluid. We are a manufacturer of stainless steel filters, and one of our customers uses DOT 3 brake fluid with our filters. We use an epoxy resin in our assembly of the filter.
A: DOT 3 brake fluid is a tough one. Most hydraulic fluids act as a paint remover when exposed to an organic finish.
Brake fluid will seriously attack conventional polyester and hybrid powder coatings. Standard epoxies fare better, but only a high-performance epoxy will adequately withstand regular exposure to the DOT 3 material. Epoxies formulated for decorative purposes don’t have the chemical resistance needed to thwart the aggressive solvating ability of the fluids used for hydraulic systems.
Therefore, I suggest you specifically ask your powder supplier for a brake fluid-resistant epoxy. These have been commercially available for years, so you shouldn’t have a problem getting the right material for the job.