This is our custom head wrench.
You can use it to hold the hotend in place while removing the nozzle. The wrench provides a tight fit around the red rubber of the hotend. Because this tool will be made from the same material which you print with, you have to be aware that if it touches or is in too close of contact with a hot part (such as the heated nozzle itself) it may melt or warp, rendering it ineffective for the job intended.
IT IS VERY IMPORTANT THAT THE HOTEND REMAIN STATIONARY WHILE REMOVING THE NOZZLE, AS THE FAILURE TO DO SO CAN RESULT IN DAMAGE TO THE HEATER AND TEMP SENSOR CABLES, RESULTING IN FURTHER UNNECESSARY PART REPLACEMENT.
Please also keep in mind that the more internal structural support you use in your print, the stronger your tool will be; you can of course use PLA for this print, but in this case, as far as heat resistance goes, ABS may be a preferred alternative.