Do they do anything useful? I haven't found any use for them yet.
You can slice off enemy parts with it but that's a waste of a turn. I suspect you might be able to get through blast doors with a plasma cutter but I've never tested that.
Welding Torches are pretty much just weak tool-weapons you might use if you have absolutely nothing else. Plasma Cutter's on the other hand do have one (perhaps two) useful characteristics you can discover among their stats...
CogGod has spoken! (Hi! I'm loving the game so far. Only played it for a week.)
Btw, I just found the Storm Laser in the Lower Caves in my farthest run yet. I'm tempted to take it just to be able to fill out the wiki page, but its huge size will require me to invest my next evolution in weapons. What do you think--shall I take a risk for science?
Welcome and glad you're enjoying it--good to have some fresh players coming in even while development is on this month-long hiatus :)
I see your other discussion here (http://www.gridsagegames.com/forums/index.php?topic=517.0).