Cambridge Polymer Labs (quest)

Cambridge Polymer Labs is a side quest in Fallout 4. The point is to find chemical samples in the abandoned Cambridge Polymer labs and complete a 200 year old science experiment.

Detailed walkthrough
Upon entering the Cambridge Polymer Labs, the Sole Survivor is greeted by a Miss Nanny robot named Molly. She asks if the Sole Survivor has come to fill a job position. Answer yes and Molly will give the player character a one question survey for qualification asking whether or not the player character has any research experience. Based on the player character's decision, varying items will be given just before entering the clean room.

Expressing confusion results in being given the position of Janitor, a mop and a Green mechanic jumpsuit. Simply saying yes will give the player character the position of Researcher and is provided with a lab coat and clipboard. There is a speech challenge on the response "You need me" and if the player character succeeds, will be given the position of Sales Coordinator, a dirty tan suit and a pen. Failing the speech challenge nets the position of Lab Assistant. Threatening Molly results in being assigned a position in security, and being given dirty army fatigues, a stun baton and a pair of patrolman sunglasses.

Molly will then ask if the Sole Survivor would like an orientation before beginning work. If the player character agrees, she will move into a side room with a broken slide projector and relate the history of the company. Once the orientation is complete, the Sole Survivor is asked to change into suitable attire and Molly leads the player character through a changing area with sets of lockers. Molly then welcomes the Sole Survivor to the team and mentions that the rest of the research staff will be found in the facility just beyond the Clean Room.

''Note: this is the last chance to leave and switch followers before being locked in. Curie has a significant affection boost (69 points) for completing the research, so it might be beneficial to retrieve her before moving forward.''

As soon as the Sole Survivor enters the Clean Room, Molly locks the door and informs the player character that Director Elwood has issued a mandatory overtime edict to the staff and that no one may leave the laboratory until the project has been completed. The room will then fill with high-level radiation, though Molly will decontaminate it shortly. The player character may then ask Molly questions, but her responses are generally that the player character should look at the research already done and see if it can be moved forward.

Just past the Clean Room, the player will come to a room with a terminal directly in front and a large machine called the Polymer Coating Applicator filling the right side of the room. The Terminal will have the research data of the experiment that's been performed up to this point. The player will learn about the Piezonucleic Polymer process to coat power armor so that the armor can utilize radiation in a different capacity. To complete the project, the Sole Survivor must supply the Applicator with the reagents Lithium Hydride and Gold in addition to the radioactive material, U-238. Sitting right on the Applicator is a silver canister that contains Unidentified Sample 11317, which when inserted into the Applicator will identify it as Hydrochloric Acid. At this stage, the Sole Survivor does not have any of the components needed to finish the project, so the rest of the facility must be explored.

There is a door leading from the room with the Applicator out onto the ground floor of the rest of the research facility which is filled with feral ghouls. It is a relatively small facility so it's likely the ghouls will all awaken at once (there are 8-10 total) when combat is initiated. Once the ghouls are dead, the Sole Survivor is free to explore, however an occasional ghoul might crawl from a hiding spot.

Looking into the facility from the door of the Applicator room there will be 2 doors on the opposite wall, a staircase on the right leading up to the second level, and another door to the right at the bottom of the stairs. Start with the left hand door on the opposite wall and find on a table in that room Unidentified Sample 3111 (Lithium Hydride). The right hand door leads to another small lab containing Unidentified Sample 413 (Gallium). Leading from this room is another door into another small lab, this one contains Unidentified Sample 65 (Tungsten) and a wall-mounted Terminal that opens the Containment Room which contains the sample of U-238. The player can see into the Containment Room through the windows just behind the wall terminal and opening the room causes alarms to sound and a glowing one will boil up out of the standing water in the Containment Room. The Containment Room can be accessed via the door on the ground floor at the bottom of the stairs and to the left of the one that leads to the Applicator room.

Up the stairs on the second level, there will be explorable areas on the left and right. At the top of the stairs, facing into the central chamber, there will be thin walkways extending out on both the right and left. On the right the walkway will be damaged and the player must jump to reach a platform with a locked door and a wall mounted Expert level terminal that will unlock it. At the end of the left walkway is an open room in which the player will find Unidentified Sample 49 (Cobalt) sitting on a desk. Near this desk is a ramp leading into the ceiling ducts. Following the ducts around and dropping through the hole at the end will allow access into the aforementioned Expert Locked room for players who cannot open the door via the wall-mounted terminal.

This is Dr. Wilfred Bergman's Lab and the final reagent, Unknown Sample 611 (Gold), can be found sitting on a desk next to a Terminal. The terminal will have several options on it, but the most crucial is "Facility Defense System". If that is selected, the player is given the opportunity to use the emergency override due to a facility breach. This will fulfill the optional objective of finding another way out of the facility but activates all defenses in the facility including turrets and Molly, which means the player will have to fight their way out of the facility.

Alternatively, the player can choose not to override the defense system and complete the research project using the final reagent sample just acquired from Bergman's lab. Make note that the Terminal-locked door has a Tesla trap just above it, so be sure to disarm the trap before leaving Bergman's lab as this door is the only way to exit the room. Return to the Applicator Room with all of the collected components.

The Polymer Coating Applicator has two receptacles to the left of its terminal screen for the reagents and one receptacle on the right for the radioactive material. Place Unknown Sample 3111 (Lithium Hydride) into the left reagent receptacle and Unknown Sample 611 (Gold) into the right reagent receptacle, be sure to note that they must be in these exact positions or the process will not initiate. Then place the U-238 into the receptacle for the radioactive material. Access the Applicator's terminal and select to start the process. If the components were placed correctly, the Applicator will begin processing and produce the Piezonucleic power armor, a unique Legendary power armor piece.

Once the process is complete, the Sole Survivor can go inform Molly that the project is a success. She will then unlock the Clean Room, but adds that The Director will be impressed and will want to meet the Sole Survivor. Following her will lead to The Director's office on the second floor of the main entrance area. Upon opening the door, The Director, now a Feral ghoul, tries to attack the Sole Survivor. Molly intervenes re-informing The Director of company policies about assaulting co-workers before killing him with her saw arm. Once he is dead, Molly pays the Sole Survivor for their efforts (in pre-war money), apologizes on The Director's behalf and shuts herself down for good, ending the quest.

Be sure to loot The Director's office and use his terminal before leaving the building.

Experiment Samples Numbers & Names

 * The Sole Survivor gets a special Piezonucleic power armor when combining U-238 with (Sample 611 Gold) and (Sample 3111 Lithium Hydride).
 * 11317 Hydrochloric Acid (base ID 0009bc88)
 * 3111 Lithium Hydride (base ID 000a50f7)
 * 413 Gallium (base ID 000a018c)
 * 49 Cobalt (base ID 000a0190)
 * 611 Gold (base ID 000a50f5)
 * 65 Tungsten (base ID 000a018e)

Bugs

 * Rarely the player character will be unable to pick up the radioactive isotope U-238.
 * After completing the quest the player character will be stuck with the rest of the components (Gallium, Cobalt, Hydrochloric Acid and Tungsten) in their inventory. A solution is to use a companion to attempt to pick up the item in Cambridge Polymer Labs until inspect chemical reagent appears. Slowly approach the tubes and you can place multiple reagents, thus removing all quest items from inventory. Another solution on PC is delete the items through the command console, using the command.
 * After Molly shuts down when completing the quest, the quest log will mark the research portion of the quest as failed. The player will still have the Piezonucleic chest armor.
 * If the dialog with Molly is bypassed (e.g. you sneak past her or ignore her) and the terminal in the Director's office is accessed and the lockdown cancelled, the first stage of the quest will no longer be able to initiate and the only option to complete the quest will be to trigger security and kill Molly.
 * When closing the door to the containment chamber after retrieving the Uranium (e. g. to silence the alarm) your companion may get stuck in the chamber, even after opening it again, refusing any movement command through the (theoretically open) door.
 * After creating a prototype, a quest notification for "Complete the research project" may appear, but the quest stage will not be marked as completed or "greyed-out" in the Pip Boy. You can still speak to Molly (if not hostile) and proceed to the Director's office to complete the quest, but this will cause "Complete the research project" to be marked as FAILED in the quest summary in your Pip Boy.
 * It is possible to complete the quest without doing the research project. Kill the first Molly that appears, and another Molly will appear from a normally-inaccessible room. Collect the CPL Director's Key from the first Molly, unlock the Director's room on the second floor, and kill the Director, then go back and kill the second Molly. The quest will then complete.