I bought a metal washable air filter to replace the disposable filter in my ceiling air return duct. As the air flow goes on and off, the metal filter is making a banging noise at it is either sucked up against the metal frame or dropped onto the metal cover.

I'm trying to come up with a way to pad the frame. Is there a product available to to do this? Most of my ideas are for products that are too thick, such as cabinet door bumpers. Would the soft side of velcro strips work?