Very cool!
I did a Thor Costume many years ago for Halloween.
The hammer was made from a couple of pieces of 2 x 4 with beveled edges, a wooden shovel handle and wrapped in leather.
For a helmet, I used a metal strainer from the kitchen, wrapped it in aluminum foil and glued some cardboard wings that had been painted silver to it.
The hammer was given to a friend's son, who was named Thor, for his birthday.
Look forward to seeing your progress!