From Discord:
After a bit of experimenting I have found out how to replicate bound cards
I just turned my 2 bound alchemists into 6 bound alchemists
Upgrade every card you have of a certain card (at least one of them must be bound). Upgrading a card with a bound card makes the upgrade bound. When you unupgrade an upped bound card (unupgrade every upped version you have to do this), they just turn into 6 bound cards, not the original amount
This should work with any card conversion