I've noticed when heating up the hotend to maximum operating temperature to tighten the nozzle against the heat break, after putting a wrench on the heater block, the temperature of the heater block drops by as much as 60 °C. Do you ignore this or have a procedure to correct?
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1$\begingroup$ Good Followup Question! $\endgroup$– TrishCommented Feb 2, 2021 at 18:56
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1$\begingroup$ I never tighten when hot and never had a leaking nozzle or heat break issues. Problem solved! 😃 $\endgroup$– 0scar ♦Commented Feb 2, 2021 at 22:17
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$\begingroup$ @0scar Torque wrench, hmmm? $\endgroup$– TrishCommented Feb 3, 2021 at 12:32
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$\begingroup$ How big is your wrench?! $\endgroup$– user77232Commented Feb 3, 2021 at 14:14
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$\begingroup$ I use a 7" channel locking wrench on the heater block and a M6 driver (screw driver like handle) on the nozzle. A driver over a wrench tends to limit torque. However, it feels like I could twist the nozzle in two even with the driver if I tried. $\endgroup$– Perry WebbCommented Feb 3, 2021 at 14:34
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1 Answer
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Mitigating "heat loss"
Technically, we don't lose heat, we have a drain of thermal energy out of the parts, but let's stay simple.
To combat the loss into the holding/steadying wrench, I use a vise: it might lessen the heating curve by the added thermal mass if used bare, but by adding two pieces of wood on either side of the heater block, I can insulate the block against the thermal drop from the steadying vise and atop that prevent scratches.
If you use an adjustable wrench for the heater block, one can add wooden "soft jaws" with a little cyanoacrylate glue, otherwise, some painter's tape or Kapton might aid.
It might help that my small wrenches have a super sturdy surface coating making them rather comfortable to use when left out in the cold and prevents rust. This layer also seems to prevent the flow of thermal energy into the wrench. Note that they are not chrome-plated but more like an enamel-look, a glassy powder-coat or actually lacquered.
Conclusion
When I need to mount something installed on the printer, I do the tightening as quickly as possible - the temperature of the measurement point and the temperature of the nozzle getting pressed into the heartbreak do not drop in the same instance, the nozzle will still be at the aimed for temperature when the thermosensor already has dropped.
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$\begingroup$ Besides short durations, I'm going to try wrapping the jaws of channel locking pliers with Kapton tape. This helps with grabbing the heater block. However, the nut driver on the nozzle would seem to have the greatest effect on the temperature of the nozzle. $\endgroup$ Commented Feb 3, 2021 at 12:24
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$\begingroup$ might be my cheap 15€ wrench set... that is coated in some fashion. $\endgroup$– TrishCommented Feb 3, 2021 at 12:40
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$\begingroup$ The problem with most coatings is they aren't made for high temperatures. Kapton does block IR. While it's only rated to sustain 232 °C, it can go up to 704 °C for short durations. Any coating would probably need the ability to replace and not leave residue on the heater block. $\endgroup$ Commented Feb 3, 2021 at 13:52
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$\begingroup$ @PerryWebb possibly... The main thing is exposure time. Doing it quick $\endgroup$– TrishCommented Feb 3, 2021 at 13:55
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1$\begingroup$ I do it quick, wait for the heater block to recover the temperature, then check quickly. $\endgroup$ Commented Feb 3, 2021 at 14:29