I never tried it but I offer this much: 12 volts is a bit low, 18 or 24 would probably work better. I have an old "Lessons In Arc Welding" from the Hobart trade school from the '50s. They started everyone off with bare rods, E-4510 straight polarity. The reason given was that the bare rod is more dificult, and if You can do OK with them, You will do really well with coated rods. Like everything McGuyver did, it was theoretically possible, but don't count on a TV show to get the details right.