I have a wood burning stove in my house that developed a smoke leak in the pipe. It is a single wall stove pipe and it appears to have been sealed with silicone of some kind. I removed all of the old caulk and used a high temp. caulk but it is designed to harden when it dries so it is not flexible. As the stove heats up and expands the caulk cracks and opens up allowing smoke to escape. What is the right product for this application and where can I get it? Lowes had nothing but fire caulk.