I needed to go out of town on short notice so I went to tractor supply and picked up this little gun safe and screwed it to the frame on 3 sides (back, side and bottom). Only problem is the lock could be defeated just by drilling it out. So last week I got the biggest heaviest hasp I could find. I plasma cut a hole in the backing. Then this morning I pulled out the gun safe took it outside and welded it up. Throw a big fat contractor lock on it and it should at least be flunky teenager and incompetent crack head proof which is about 98% of who breaks into houses around here.
Now put a steel box over it, so bolt cutters can't get to the lock. Forest service does it all the time with their gates.
Just take a small section of channel iron and weld it over the top of the hasp, and use a ring style lock.
That was my old 120v Lincoln transformer mig running Lincoln L-56 in 0.025 and CO2. The welds look better in person.