MP&C
Member
I guess I'm not understanding the need for Ospho if the panel was media blasted. Did the media not remove all the rust? My experience has been that any Ospho residue that gets (got) missed causes adhesion issues (delamination) for epoxy primer. Whereas the abraded surface from media blasting gives a good tooth for the epoxy and doesn't have adhesion issues. I've since eliminated the Ospho step.
In a similar case, a local machine shop did some powder coating for us on some brackets and rather than media blast the part, used a "pre-treatment" solution to rough up the surface of the part. The powder coat delaminated from simply assembling/tightening the hardware. For any powder coating I've been involved in since, the part is always media blasted before it leaves my shop so the powder coater doesn't need the option of the "easy" process. I have experienced ZERO instances of delamination in doing so. Snake oil is snake oil, and shortcuts normally show themselves sooner or later.
In a similar case, a local machine shop did some powder coating for us on some brackets and rather than media blast the part, used a "pre-treatment" solution to rough up the surface of the part. The powder coat delaminated from simply assembling/tightening the hardware. For any powder coating I've been involved in since, the part is always media blasted before it leaves my shop so the powder coater doesn't need the option of the "easy" process. I have experienced ZERO instances of delamination in doing so. Snake oil is snake oil, and shortcuts normally show themselves sooner or later.
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