Hi, I have an antique iron birdbath -- it's really beautiful. of course, when i fill it, the water turns rusty in a couple hours, scums over on the surface, and looks very unappetizing, i'm sure, to the birds.

i tried scouring the rust off, drying well, then spraying with several coats of rustproof clear spray sealer, but the problem continued after a few weeks. i thought about clear epoxy but not sure if I could 'paint' it on or would it sag down the sides?

does anyone out there in metalworking land have a solution? i don't want to change the metal finish or color, just make it rust proof so the water isn't icky.

thanks!