Long after escaping Castle Dimitrescu and avoiding certain death from Donna and Moreau, Resident Evil Village pits players against Karl Heisenberg. The most dangerous and enigmatic of the four Lords, Heisenberg has ulterior motives that don't necessarily involve Ethan and as such, leaves him at the mercy of the horrors within the factory.
Fortunately, the Factory also contains several different molds that players can use to create important items in Village, including Heisenberg's Key. The key mold doesn't have a direct path to its location as players will be required to pick up a few other molds first, though this guide will go into detail on the location of each.
Find the Casting Machine in the Foundry.
Take the back left hallway (facing the Casting Machine).
Behind the "dormant" Soldat, grab the Horse Relief Mold.
An intense encounter with Sturm, commonly known as "Propeller Man," forces players to escape down a trash chute, landing on level B4. Following some dimly lit corridors and Soldat grunts, players will come across the Casting Machine in the Foundry. Players should make note of this location on the map and become well acquainted with the adjacent hallways, as it will be referred to quite a bit.
Facing the Casting Machine, the hallway to the back left will lead players to a small platform with two doors, though one is currently inaccessible. The other leads straight to the horse relief mold. Aside from the usual enemies hiding in the darkness, players will also encounter one that apparently lies dormant in a chair. Keep an eye out for this one, as grabbing the horse mold will inexplicably restore the defunct Soldat Eins to life and send him looking for blood.
Finding The Cog Relief Mold
Open the right hallway (facing the CM).
Unlock access to the CM and enter the generator room.
Retrieve the cog mold from the locked room.
The horse relief mold opens up access to the hallway on the right side and leads players to Heisenberg's Quarters which also requires a Heisenberg Key. A key part of Heisenberg's Hammer is inside that room, though it's possible to backtrack for it later, so no worries. Players will eventually find themselves at another locked door and a hallway full of Soldats, though none of them will attack - yet. Follow the hallway down to unlock one of the doors leading back to the Casting Machine. Take note, but there's no need to spend too long here.
Back in the scary hallway, players will find a partially exposed wall at the end. This is the location for the second half of Heisenberg's Hammer so whether by pipe bomb or other explosive, that wall is coming down. Otherwise, continue into the generator room to see that the backup generator is off and, as expected, requires a mold - a cog mold.
The stairwell will lead players to the aforementioned locked room and the case containing the cog mold. There are also some important Resident Evil Village files on the table for players looking to get the Bookworm achievement. From here, players can exit out to the same Soldat-filled hallway, though always expected the unexpected. The first four Soldats give more attention to their slumber, but the last one finds Ethan far more interesting.
After putting him back to sleep, players will need to take the cog mold to the backup generator. A lot of machinery and lights turn on, along with a monologue from Heisenberg himself. Oh, and a Soldat Eins drops from a conveyor belt ready for a fight, so watch out.