Now I understand

... why bronze sculptures are so expensive. Basically, bronze is hard to do. The whole process is very time consuming and requires many kind of skills and a wide variety of specialized tools and equipment. In addition the material costs. Bronze is made up of 95% copper and the other 5% of other metal alloys. Copper is a very expensive metal, the price is increasing dramatically due to massive construction demand in countries such as China.

I'll need only one more visit to the foundry and then my works are ready!