In trying to figure out the best way to instal my insert, after trying out various elbows, offset adapter, etc. I think the best way for me would be to cut out even more of my damper frame than I have so the liner can come in at the right angle. This is a bit cut, heck, I'd even consider removing the damper frame alltogether, except that it seems partially embedded in the masonry. I made my original cut with a sawzall, and that was seriously hard work. This is going to be a bigger cut and I dread the idea of the sawzall again. Someone mentioned it is much easier cutting with a torch. Has anyone used a oxy torch to cut cast iron? What are your thoughts on this? Is this a manageable task for someone like me who hasn't cut with a torch before?