The top hatch was made from scrap 1/8 steal plate from road side pickup. Scrap metal scavengers are plentiful in El Paso Texas and metal falling off of open top semi truck is just left with the drivers hoping that no one saw it fall off their truck as it would be impossible to get it back on top of the 10 foot tall side boards by them selves. I made a very nice lid with my chop saw hand grinder and welder in an afternoon. I had to buy the hinges. The frame was made out of 4X4 angle iron scrap I had laying around that I got in a bunch of other stuff that I used in another project.
If there was ever a war then you will either make your supplies at home, salvage or do without.
American Handbook on Guns Ammo and Freedom