J.M.
here is how I bury the carbon fiber rods....
I turned the tip down on this soldering iron in my lathe to about 1/8 dia.
then I bent it at the angle shown in the pic.
I lay a 36" metal scale where I want the groove..... then use the iron to burn the groove.
It takes practice and is not easy at first. I then hot glue the carbon fiber rod in and then tape over that.
