Hello

I'm just starting out making fur felt fedoras. When it comes to trimming the brim I'm trying to find out how to overwelt or under welt the brim. I know it's an old technique but I have seen it this season on a few high end fedoras so it seems like it may be returning. I really like this finish ( much prefer it to a petersham trim) . Does anyone know how it's done please? I have trawled the internet but am none the wiser.

thanks

Catherine