Bought a Slaymaker padlock on eBay and it did not have a key. So I decided to try and impression my first key. This warded lock was fairly easy to impression and the key is still a work in progress, but here is what I have accomplished so far. I still need to shape the bow of the key and polish it.

Rough initial key blank cut from steel bar stock

After first impression and filing

After second impression and filing

Success!
This was a very entertaining process so I imagine I will have to try to impression some other locks I have.
