Some excellent work!
On your cost of production, it looks like you just charged cost of actual materials and labor. What you might want to consider is the other associated costs that went along with the project. Things like fuel for the forge, the cost of using your tools (depreciation), the cost of the place where you did the work. While it may be your garage or backyard, There is still value in using that place which could be added to the legitimate cost of the product. There are probably other costs as well that you may not have thought about as well.
These other costs may be hard to pin down per project, so you may want to include them in your labor rate. You may want $10 per hour for your actual labor and another $5 per hour to cover your "shop" costs bringing your labor rate to $15 per hour. You probably want to come up with your own number for your shop costs, but you get the idea.
Just my thoughts