Hello, I have begun to make a pattern rifle stock for use in a duplicator. I purchased an unfinished short action Remington 700 stock from Richards Microfit and I am modifying the inletting and contours to fit my Alamo Precision XM length action and Bartlein #3 barrel. I am doing the material removal using a drill press, cross-slide vise, chisels and abrasives. My question is that for holes I need to fill and contours I want to build up, what material should I use? Would something like Bondo or similar automotive putty work? I don't care how it looks because it's a pattern, but something that's fast drying, easy to shape, and relatively durable is preferred. Thanks!