I made a leaf casting a couple of weeks ago to use as a birdbath. This is my first project like this. I used straight concrete mix. After about 6 days I put two coats of a concrete sealer on it (sorry, don't know the brand as I was using what the nursery supplied). After several days, I started to use it and it won't hold water....just sort of seeps through. What can I do to correct this problem? I read that I could use a mix of straight portland cement and admix to brush on it to help seal it. Can I do this on the underside so that it doesn't destroy the pattern of the leaf on the inside, or is that not enough to stop the seepage? I also think I didn't pack the concrete enough in spots as it's not completely smooth all over. Could this also be causing the seeping problem? Any way to salvage this project? I appreciate any help you can provide. Thanks.