The crazy Hermit can rebuild it, better than before. He's going to send you off to the Washburn Refinery. You will get this mission immediately after completing the mission "Crazy About You".
True Vault Hunter
From his house, head south and drop down a level. You should see a gondola system that will take you across the canyon back to the beginning of the Rustyards. Return to the Wurmwater and head south to find the Refinery entrance. There is a Pirate camp stationed at the base of the elevator that will take you up to the Refinery. It is likely in your best interest to deal with them before trying to get on the elevator because the elevator can take a little while to get to you.
When you get to the top, be careful because there will be a Badass Loader at the top. You can deal with him however you like (the pipes will probably be your best protection) or you can run right past him and enter the refinery. While inside the Refinery, you're going to encounter all sorts of Loaders while searching for the parts you'll need.
Use the vending machines near the entrance if you need to and then make your way north into the Refinery proper. You'll come across a JNK Loader first which may be familiar to you if you've finished the main story of Borderlands 2. They have two weak eyes on their body as well as the normal joint weak points. Kill him and go into the next room.
You'll come to a large room with a bunch of Loaders including EXP, PWR, and BUL Loaders. You'll have to destroy these to continue. It may be best to hang back a little from these enemies so that you have space and elevation on them. This will also slow them down in approaching you a bit. Keep working through the Loaders until there are no more and then head to the east side of the room to find stairs that will lead you up and out of this room.
This will bring you to a small storage room where you will find your first sample of poly-kryten on a table. Go up the large stairs in this room and you'll come to a peaceful area with a few different paths. In the NE part of this area, you'll find the C3n50r807 who will give you a mission called "I Know It When I See It". From here, head west to continue but watch for a Badass Loader to appear through a door on the left side. If you back up a little, you can put a good amount of distance between the two of you and give yourself some good cover as well. Kill him and follow the hallway opposite the door he came through.
At this point, you'll enter The Arm. At the end of the hallway, turn right and kill the lone JNK Loader that you find there. Beyond him will be a spawn room for Loaders. When you enter, you'll be attacked almost strictly by EXP Loaders. You're going to get attacked by a lot of them and the best thing you can do is to keep moving. Try and run laps around the room including up and down the stairs at the back of the room. After a decent number of EXP Loaders try to attack you, you'll be attacked by a couple of JNK and GUN Loaders.
Once you've killed all of the minor Loaders in the room, a Badass Loader will appear at the back left of the room. At this point, you should probably back up a little ways to the long hallway. From here, you can use the corner for cover while fighting him and you'll have a long way to go to get to you. With him out of the way, go through the door that he opened for you to get to the next storage room and your next sample of Poly-kryten.
After grabbing the Poly-kryten, drop through the grate and follow the hallway as it zig-zags ahead. The next room is pretty rough with a lot of high end Loaders so be careful. Like last time, you'll be attacked by a few EXP Loaders to start with but you'll quickly find yourself finding GUN, PWR, JNK and ARR Loaders. Don't get too far ahead because you can easily get surrounded and die. Instead, move forward and try to take out as many enemies as you can. Move back only when you need to because you don't have a whole lot of room behind you. As you clear out most of the Loaders you are used to, this is when you will encounter the tougher ARR Loaders. They are not quite Badass Loaders but they are pretty tough and have shields so be careful around them.
When you've cleared the area, go in the direction of the waypoint. You'll find stairs but instead of going up to the door, go down to the area below the stairs to find a Hidden Vault Symbol. Now you can go up the stairs. Go up a couple floors and go through the door. This will lead you to another room with more of the Poly-kryten but be careful because there's a GUN Loader right next to it.
From this spot, turn north and follow the hallway to find the Lair of the Lecher-Bot. This is where you can complete the objective of "I Know it When I see it". Kill the P3RV-E Bot in this room and then check around the room to find the various magazines that he's left behind. Be careful of the other Loaders in the room (likely JNK Loaders). With the enemies killed, move through this area and the next but watch out for the couple of bots on you may encounter along the way.
Eventually, this path will lead you outside which is exactly where you want to go. Outside, you'll encounter a couple of Badass Loaders but there's a lot of cover around here. The best cover at are the half height platforms which are just tall enough to protect you but short enough for you to shoot over when you stand up. Be prepared, however, because once these two die, a much larger Loader called H3RL-E will appear to the north. You don't want to have your back to this when the second Badass dies.
For me, the best cover was actually the Hyperion dump truck not far from H3RL-E. It was tall enough that he couldn't hit me over it, even with his trebuchet. Find tall cover and stick as close to it as possible to prevent the Trebuchet from being a problem. Start attacking him with an electric weapon to take down his shield layer. Once that's down, switch to a corrosive weapon to kill him. A few good placed shots will take him down quickly and thankfully he moves pretty slowly, allowing you to move around (always sprint) and keep your distance.
With H3RL-E dead, go through the large open door nearby that leads SW from here. In the next hallway, you'll encounter a JNK Loader but just beyond him, you'll find a wide room with the Poly-Kryten you are looking for. Keep going along this path, past the next JNK Loader and you'll be able to drop back down in The Arm. From here, drop off "I Know It When I See It", pick up "Don't Copy that Floppy" at the same time and then leave the Refinery.
From Washburne Refinery, you can fast travel to the Rustyards. From the Fast Travel point, you can head right instead this time and take the gondola back across. From here, the anchor up to Herbert's place isn't far. Talk to him and he'll make the piece of the compass for you. When you are done, give Herbert his gift and bring the last piece of the compass back to Captain Scarlett for your Reward.