Repairing MDF shelf finish


Does anyone have a good technique for repairing the plastic finish on an MDF shelf?

I have a SolidSteel rack and one of the shelves has a ding in a very noticeable place. The plastic coating has been knocked off, but the underlying particleboard is OK.

I'm thinking there must be some product that would adhere to the particleboard and could be smoothed in and made to match the existing plastic, and then painted black when it hardens. Any suggestions?

Thanks - David
magister
Thanks for two good ideas. I'll check out the glazing putty, which I'm not familiar with. For some reason I've never been fond of plastic wood, but it could work here. Unfortunately, the shelves on SolidSteel racks only go one way, and the chip is on the front top.
Yes, I know what you mean about them only going one way. Don't they have holes that line up on the bottom? Can't these be re-drilled?
I don't have access to a drill press, and I woulnd't dare redrill them without one. If the holes are not identical in depth, and straight, the shelf won't ever be level and solidly supported. If I can't get a goodlooking repair I might have to go this route.