There were a few important things Han Mengli needed to forge before he could get anywhere with making weapons.
A hammer and anvil were very necessary to refine the weapons he made, so he made those first. Following that, he crafted a few extra metal plates to make formations out of.
The dagger he had made previously was turned into a sharp pen to be used for making formations.
Once they were all ready, he needed a place to store them. That took some more time as well. He dug his way into one of the spirit stone mine openings and emptied it. That would be where he would hide everything.
Once that was ready, he started making the weapons.
He made a single sword each day, the entire thing forged from metal all the way through. He hid the sound of his hammer striking the anvil with the many sounds of axes hitting the walls.
At first, it was hard, but the more he continued, the better he became at it. After a few weeks, his weapons reflected that improvement as well.