As Chevy said get a boat load of tungstens as you'll go through a few. What material you gonna concentrate on. What you making the box out of. Ali I assume. Have you done AC before.
tbh i spent a long time thinking would i need AC that often and i just couldn't warrant spending the extra at the moment however i don't know where i'll stand in 6 months, i may be looking for an ac/dc machine if the need/desire/funds is there