I have a birdbath -- definitely not concrete or fiberglass, probably
some kind of plaster. Apparently there was some sort of coating on the
inside of the bowl and after a freezing night or two the coating spalled
and the bowl developed some fine cracks and now leaks. I'm looking for
some sort of coating I can use inside the bowl to stop the leaking. One
of the local hardware stores recommended the water-based latex form of
Drylok masonry waterproofer -- I wish it was available in less than a
gallon-sized can. Someone else recommended some kind of bitumen paint --
but didn't know the brand or where it was available. Obviously I don't
want anything that'd be toxic for the birds.

Anyone had experience with sealing a birdbath, fountain or, perhaps,
something like a small koi pond?

Thanks in advance!

Northe
Green Valley, AZ