Once you take the metal out of the forge you only have a few good swings with your hammer before it cools down and you have to put it back into the forge. Our friendly safety instructor at Makerspace noticed that it was taking me longer to get my points hammered out on my iron. He handed me a lighter hammer, which instantly made the control on my swing much easier to control! (I asked for Mjolnir but was told the hammer was on a Secret Invasion). Since you're having to hold the metal with tongs(it's around 1400 Celsius when you take it out of the forge) in one hand and the hammer in the other, your arms get exhausted.
“Working with the forge and hammering metal all day was one of the most psychically exhausting things I've ever done, and my arms were sore for 2 days.”
Now I have an awesome S hook that I mainly use to hangs my bras on at the house haha! Next step: make Geralt of Rivia's witcher sword