Prep M is a "wash primer" that improves bond strength of SMP-based products on most non-porous substrates. Use Prep M on non-porous substrates. In cases where high thermal or physical loads-especially under humid conditions requiring ultimate adhesion-use Prep M. A clean, dry and grease free substrate is necessary for ultimate adhesion. Read and follow instructions in Technical Data Sheet and Material Safety Data Sheets. Pretreatment of plain aluminum, steel, copper and brass surfaces Pretreatment of powder coated metals. Pretreatment of lacquered metals (conduct a pre-test) Pretreatment of polyester (FRP) Pretreatment of ABS Pretreatment of PVC