I've seen serious hot knifes for many, many $. And I've often seen the suggestion of using a fine hot soldering tip to simultaneously cut/melt and sear the fabric edge, that tip against a steel straight-edge on a sheet of glass.
But, a sewing forum just pointed to this hot knife not mentioned before here: a tip that holds an Exacto (tm) like blade.
http://www.micromark.com/hot-knife-a...iron,9763.html
Bookmarks