I needed to remove thick white paint from an old cast iron door knocker. The remover did eventually work, but didn't have any real effect after the first couple of applications, and needed re-applying several times before the paint broke down.
I have had better, more powerful solvents in the past that take the paint of really quickly. But then maybe it's new European regulations that mean we can't buy decent pain stripper and this is as good as it now gets?