02/11/2026
Today was a day of learning. A lot of learning what not to do to be specific. I took a piece of scrap metal and cut some grooves in it with my rotary tool. This simulated cracks to be filled on the toolbox. I cut the grooves at various depths to see how the filler material would behave. I tried JB weld as well as a low melting silver solder. I found both did a fine job filling in the grooves.
This experiment was to see what performed better at filling cracks for powder coat. I will say, the silver solder is much harder to file down to blend with the parent material. It is also harder to control due to the liquid nature of it. When I did get the solder to flow, it sealed the cracks well. It is also very expensive and time consuming to prep the material.
I placed the test article in the oven after powder coat and found the JB weld sort of worked. There was a faint coating over the epoxy, but it was very visible underneath the powder. If I were to try this again, I would make the groove shallower. It was about .02” deep, and I think the thickness of the epoxy inhibits how much powder will stick to it. For surface scratches, this may be an acceptable filler.
After these tests, I decided to go the easier route and paint this toolbox. I prefer powder coat due to its robustness and relatively easy preparation, but in this case, paint won out. Also, the box is steel, and I have good luck getting paint to stick to steel. It will be more prep work, but I felt I would have to do the same amount of prep work either way since there were low spots. Since I am not familiar with the two above processes, I did not have the confidence the results would be consistent. The main advantage of painting is I could use glaze putty, which is inexpensive and forgiving to use.
I put some putty on the lid and gave it a first coat, and the results were less than stellar. For some reason a lot of crud got on the lid inside the paint booth, so it came out textured. Typing this out, I have reason to believe it may have been residual powder the fan was kicking up. Oops. There were some file marks that were deeper than I thought and the paint did not fill them. Also, some of the solder did not blend as well into the parent material as I thought. I cut my losses on that and stripped the paint off and went back to body filling and sanding.
After a bit of filling and sanding, they are ready to paint next time I am in the shop. While I did not make as much progress on this as I had hoped, I am looking at this with the perspective of lessons learned for future parts and how to go about preparing them for painting and powder coat. For welded steel parts I will probably paint them with Bondo, and brass parts will get the powder coat treatment for sure.
I did powder coat the hinge rod and nuts, so I was able to complete that!