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Let's say I'm soldering a PCB, and re-holster my iron, still hot at 320 °C, to fiddle with some components or documentation. How long will it be before tip damage occurs?

In other words, what is the recommended maximum length of time a soldering iron can be kept hot? At what time should it be turned off to prevent tip damage?

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  • \$\begingroup\$ High-end soldering irons will turn themselves off, or go into a low-power mode, when you put them in the holder. When I'm using the ones I can actually afford, though, I turn them off whenever I'm doing anything other than soldering for longer than a minute. \$\endgroup\$
    – Hearth
    Apr 20, 2021 at 0:48
  • \$\begingroup\$ @Hearth Or you could have one like mine: an auto-sleep that activates at random times. I have to shake my iron like a rattle to wake it up. (Good thing it can be disabled) \$\endgroup\$
    – midrare
    Apr 20, 2021 at 0:54
  • \$\begingroup\$ 420C seems awfully hot. Maybe if you have a long thin tip or you are soldering something with a big heatsink. I’d normally be around 100C south of that. \$\endgroup\$
    – Kartman
    Apr 20, 2021 at 1:28
  • \$\begingroup\$ @Kartman I admit I've been winging it for the most part (most of my soldering has been 23 awg wires to buttons, nothing sensitive enough for me to ruin). I've decided to learn to solder "for real" and am only 3/4 through the PACE lessons on Youtube. I'm going to edit my question, so let's just pretend it was a sensible temperature from the beginning :P \$\endgroup\$
    – midrare
    Apr 20, 2021 at 1:40
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    \$\begingroup\$ Be aware that the difference between good tips and bad tips for high temperature is night and day. I use good tips and despite foolishness like leaving it on overnight and somewhat abusive use scenarios like being thrown in a tool bag, the tip that came with my Hakko iron is still fine. Hakko is basically near the low end of the high end or maybe the high end of the hobbyist market. I can get 80 knockoff tips on aliexpress for the cost of one, but they wear out rather fast. \$\endgroup\$
    – K H
    Apr 20, 2021 at 2:16

1 Answer 1

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There is actually no "recommended maximum length of time a soldering iron can be kept hot", just as you might assume - the longer, the worse.

Regarding the idle time, these scenarios came up to my mind:

  • manually switch the solder after few minutes
  • let it go until the tip is gone - maybe you find out it can last longer than you would expect and then just buy a new one
  • use your solder's sleep feature although it does not work great (as you claim) and live with it
  • and finally - buy a new solder with better sleep feature.

And last but not least - your temperature of 420 °C is unnecessarily hot, which affects the tip durability a lot. The tip life decreases exponentially with temperature.

Try to find the lowest temperature that still works for you, to balance the workability vs. tip durability. JBC has a decent article regarding the topic: https://www.jbctools.com/blog/correct-temperature-soldering/

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  • \$\begingroup\$ This is one advantage of using leaded solder--it has a lower melting point, so you don't need the iron to be as hot. \$\endgroup\$
    – Hearth
    Apr 20, 2021 at 1:48
  • \$\begingroup\$ Yes one of many. You can also enjoy the smell of "forbidden fruit", for instance :) \$\endgroup\$
    – ethcz
    Apr 20, 2021 at 1:51
  • \$\begingroup\$ You know the scent is entirely the flux, not the solder material, right? \$\endgroup\$
    – Hearth
    Apr 20, 2021 at 2:02
  • \$\begingroup\$ This was meant as a metaphorical joke, thus the quotes and smiley... \$\endgroup\$
    – ethcz
    Apr 20, 2021 at 2:11

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