Is the question whether you can make DIY micarta using some fabric and JB Weld, or whether you can use JB Weld to glue premade micarta to a piece of steel?
For DIY micarta, the grey JB Weld is probably too thick and it will be hard to wet out the fabric. I have made denim micarta using West systems 105 resin and it worked okay, but commercially produced micarta is a lot nicer. I guess you could experiment with adding metal powder to a thin resin. That would probably work better than using JB weld.