I would like to find the best way to make a 31/2" MDF moulding for an arched window out of a sheet of MDF. Is it best to just find the radius and draw it out? Or should I cut it close and hold it up to the window, trace it, and then offset it by 1/8 before cutting? Any help is appreciated.
(Architectural Woodworking Forum)
From contributor G:
What kind of machine are you using? MDF does make nice paint grade moulding, but it's hard on knives.
This is done by pressing the paper tight against the window outline and rubbing a lead pencil back and forth until you get the image of the part of the window that you need on the paper. You can use the rubbing as a template or as a guideline to set up a trammeled router with to cut your molding blank (CNC if you have one).
For applying a moulding that was to have a consistent reveal, this would have been a very large problem had these openings not been templated and reverse digitized. As the previous post said, what machine will you be cutting the moulding with? Nothing compares to a quality CNC router for producing accurate, repeatable and fast templates and mouldings. If you do not have a CNC machine of your own - simply job it out to a shop that does.