I have a Rocket Hammer too. They're amazing!
It should be working. Just drag the hammer directly onto the automaton head.
If it doesn't work after a few tries, please contact the Aetherlight support crew at https://theaetherlight.com/help/contact-us.
There IS one in the Labs! Travel through both of the access teleport tubes, then travel in a south-easterly (downward and to the right) direction. Eventually you'll have to cross some ice bridges. At the end of those, there's a room with the Plasma Infusion Sprocket machine. If you keep going down, you'll come across the INFAMOUS AUTOMAYETI! Hope this helps. If you still can't find it, I'd be happy to post more in-depth instructions.
~Hanna Brassheart, C.M.
P.S. If you only bought the Season 1 pack and not the Family Season pack, you will have to buy the episodes again for the second character. If you bought the family pack, you can have all the episodes on up to 5 characters. (Accounts are linked via the parent dash, I think.)