The inside core structure and the outside mold had to withstand the pressure of about 30 tons of molten copper, and the casting had to be done in one continuous operation to prevent cracks or flaws.
Struktur inti bagian dalam dan bagian luar cetakan harus mampu menahan tekanan sekitar 30 ton tembaga cair, dan proses penuangannya harus dilakukan sekali jalan agar tidak retak atau cacat.