Guide to upgrading the default nozzle of a C2 Printer I have been somewhat disappointed at the lack of a guide to changing a nozzle from the default to a hardened nozzle. So, I am writing this guide to give the novice a procedure to follow for upgrading the C2 Printer nozzle. Please read the guide a few times before you attempt the change out of the nozzle! SAFETY FIRST: During this procedure, you will be raising the hot-end to the maximum temperature of 290 degrees Celsius. That temperature is almost three times the boiling point of water. Be aware that you could burn yourself if you do not take precautions. Pick up a pair of leather gloves from a garden center. The gloves should be very flexible as you will need some manual dexterity during the hot phase of the procedure. Have a ceramic bowl or plate handy to set the old nozzle into as it will be cooling down from extreme temperatures. Tools: The default nozzle is not hex shaped, rather it has 2 flat sides. You will need 2 adjustable 6 inch wrenches for the loosening of the old nozzle. A 7mm socket / ratchet handle for tightening the new nozzle. A pair of needle-nose pliers (or the tweezers supplied with the printer) to snatch the filament out of the old nozzle as you liquefy the old filament. And obviously, a replacement nozzle which can be ordered on-line (E3D V6 Hardened nozzle). Earlier posts to this forum have suggestions on where to buy it. Initial Conditions: If filament is still loaded on the C2 printer, use the "wizard" to unload the filament. (last item in this article: https://help.robo3d.com/hc/en-us/articles/115000722752-Loading-and-Unloading-filament-C2). The printing platform should be lowered to the home position. The printing head should be positioned to the center of the X-Y plane. Now, there are two possibilities: First) you have not printed anything with the printer (pristine clean hot-end). If this is the case then skip the next section! Second) you have used the printer and the hot-end has filament residue. Continue with the next section. Clearing the Hot-End nozzle: Note: Have the pliers or tweezers handy as you will have filament oozing out of the nozzle during this phase. Note: If your C2 printer is not powered up, turn it on now. Note: Remove the magnetic "Robo" cover plate to expose the hot-end. On the main screen, tap the "Temp Controls" button with the stylus. Next, tap the "Extruder" button. Going forward, you will use this temperature control screen for the rest of this procedure. Note: In the lower right part of the screen, you will see a blue "Cooldown" button. This button will change to a green "Set" button as you enter / alter the temperature. Once you tap Set, the "Current" temperature text reading will turn red. Once the temperature reaches the set point, the text will turn green. Use the "Delete" button to remove / alter the desired temperature setting. Using the stylus, tap in a temperature of 290 degrees and then tap the green "Set" button. Wait until the temperature stabilizes to the set temperature. While the hot-end reaches the temperature, filament will come out of the nozzle. Once the hot-end reaches 290 degrees, wait about 10 seconds and then set the temperature to 180 degrees. Repeat raising the hot-end to 290 degrees and then cooling to 180 degrees until no more filament oozes out of the nozzle. It took me around 5-6 times to finish clearing the filament from the hot-end. Changing the nozzle: CAUTION: You will be working with a very hot part! Be careful! At this point, the hot-end should not have any filament oozing out (while the nozzle is being changed). At the temperature screen, raise the temperature to 290 degrees and wait until it stabilizes. Place the ceramic bowl on the printing plate so as to catch the old nozzle. Put one 6 inch adjustable wrench on the Aluminum heater block and the other adjustable wrench on the 2 flat sides of the nozzle. Holding the Aluminum heater block steady, loosen the nozzle from the heater block. Carefully unscrew the hot nozzle from the heater block using the adjustable wrench. CAUTION: The heater block is still at 290 degrees and the old nozzle is cooling down from that temperature. Place the old nozzle in the ceramic bowl / plate for cooling down! Screw in the new nozzle a couple of turns by hand while wearing gloves!! Now the new nozzle is in place, use the 7mm socket to tighten the nozzle. When you feel resistance to tightening the new nozzle, give the nozzle a slight snug fitting. No torquing or 'gorilla tightening' the nozzle! Make sure the Aluminum heater block remains flat with respect to the front cover plate. It must not make contact with the cover plate! Now use the temperature control and delete the 290 and tap on the Set / Cooldown button. Lastly: As the Aluminum heater block cools, it will exert additional force on the nozzle / heat break internal connection at the lower temperatures. Thereby, reinforcing the seal against the flow of hot filament. Important! Run the Z-Offset wizard. Also, consider running the Fine Tune Offset wizard. As a final test, print something which will take an hour or two to complete. There should not be ANY filament showing/oozing in the hot-end between the heat-break and heater block or the nozzle and heater block. Congratulations! You have changed the nozzle successfully.