Step 1: Planning
Step 2: Materials
21-8 inch x 3/4 inch x 1/8 inch steel strips
Tig welder (as well as a little propane torch for heating)
Plasma cutter (for sizing steel strips and hinges)
Scrap sheet metal
I was fortunate enough to have a welding shop that provided the machines and some of the materials above, if these are not readily available it makes this project significantly harder and more expensive.
The tools I had already that can be purchased from a welding or hardware store were:
Insulated leather gloves
Safety glasses (extremely important)
Long sleeve 100% Cotton shirt
Step 3: Beginning Construction
Then, I cut the strips down to the size I need using the plasma cutter. Unfortunately for most of these steps I won't have pictures because I will be doing them, however I tried to take pictures of as many important parts as I could.
Step 4: Constructing the Sides
In general I found it easiest to weld the strips together in sets of two and then combine each pair.
A few words of wisdom for this step,
-Tack each end of the strips together to prevent warping while welding (Which means make a small weld at each end)
-Make absolutely sure that the strips are all level
Another method you could choose to use is to put together the box layer by layer, from the bottom up. This lowers the risk of having uneven or tilted strips, which can be a hassle to deal with.
Step 5: Joining the Sides
Now for the bottom:
For this I inverted the box and placed the bottom on the top so that it would be easier to weld together. I made one weld running the perimeter of the bottom, fusing it to the walls.
Step 6: Making and Attaching the Hinges
To do this I looked around the shop for some very thin scrap metal. When I found some I cut a strip about 1 inch wide and roughly 1 foot long. After that I cut four smaller strips from the long one (and had some extra left over for just in case). To fold them over I heated the strips with the propane torch and bent them with needle nose pliers. To get the desired diameter I rolled the hot metal around a segment of the filler rod that I had been using for the welds.
Now that I have the four hinges, a top, and a side, it is time to attach them. Because there is a large difference in thicknesses of the materials, be sure to use a low amperage (which translates to low heat), because the hinge will melt before the box does. I made a mistake on one of mine, which you will be able to see in the picture:
Now that the hinges are all attached, we can move to the coloring!
Step 7: Heat Coloring
First I wire brushed the inside and outside of the box so that I was starting from a clean slate, and then began the coloring. Lighting the propane torch, I very slowly heated until the steel began to change color. (it took about an hour of heating to color the entire box and the lid. This part is tricky because there is only a small temperature range for coloring, and the color keeps changing even after the heat is removed. When the inside is colored, cool the box (by dunking it in water) and then wait until completely dry.
Once dry, spray with the clear coat to preserve the coloring and keep any rust from forming.
The first picture is an example of the clean steel, the second is after having heated it. The second is from a different angle to catch the coloring more.