okay, so I'm new to this laser engraver stuff. i just recently bought a new cheap, entry level laser engraver. and yess.. its from china. Its a 40W co2 laser engraver and I've gotten a pretty good grip on how things work so far. Just curios about the ability it has to engrave, or etch onto metal. Ive tried to engrave onto some random things around my house so far to see if it would do anything and nothing. I can't seem to get it to engrave onto any metal surface and before i spend the money on the thermark I'm wanting to see first if the investment would be a loss cause. So the real question is, If i was to buy some would the laser be able to engrave on metal surfaces, like a knife, a gun, or scope? Thanks in advance! and please, I'm new so be easy!