Used 250 gal propane tank
and old boiler tank with rivets
flat strap 1/4" x 2" (to go around door opening)
2-4x8x1/4 plate steel (to make fire box)
5' of 4" pipe (for smoke stacks)
4x8 sheet of expanded metal (for racks in side smoker)
a lot of grinding wheel
a lot of welding supplies (i.e. oxy/acet tourch, wire welder, arc welder, welding rod/wire)
turned mesquite handles
Step 1: Find a trailer
Check local auctions or craigslist for good deals, I found this trailer at an auction and paid $20 for it. However you get what you pay for, I had to haul it back on a flat bed trailer due to fact the original rear diff was seized. Notice the fender damage you will see I repaired it a piece of sheet metal that I tack welded in place and used auto body hammers to form the curves. Then I applied BONDO to hide major blemishes.
I tore the old metal flooring out and replaced with 1/4" diamond plate (you can see that in the next step).