I have several how water radiators that I would like to replace the grills on (the lower portion that covers the pipe connections). Can anyone point me in the direction of who made these and where I can find replacement parts? Thanks!
I would see if your city has an architectural salvage store.
Since most new hot water systems would use baseboard-style radiators, these types of covers are not very commonly sold new, at least in my region.
You could also check with a local sheet metal shop and find out about having something custom made to your needs.