The only thing that I had problems with was the birdbath. The first year the paint didn't adhere to the concrete inside the bowl- the paint and primer all pealed off in one big piece a few weeks after filling with water. Last winter I brought the bowl inside by the wood stove and scraped it really well with a wire brush, then let it set there for a couple of weeks to dry thoroughly. The outside of the bowl and the pedestal were fine, so I just touched those up. After priming again and re-painting the bowl I allowed it to cure for a few weeks indoors before putting it back outside. I didn't have any problems last spring and summer and it still looked good when I emptied it in fall.
