Well, I'm starting to feel a bit better about my welder now.  I've had the trailer for just a few days and already have put the welder to work.  I wanted a lockable box to hold tie-downs and locks, and whatnot.  I had a 50cal ammo can, some steel, and a welder.  The rest is history.

Since this is my first car-hauling trailer I'm bound to have some kind of a learning curve, but after laying out all the stuff I had to go in the box, the 50 Cal can seemed plenty big, waterproof, and with a few simple mods, lockable.

Of course, then I put a Jeep on my new-to-me trailer and towed it to the office, quickly discovering I needed more stuff, and might be running out of room in the box pretty soon.