Soldering guns demagnetize pickups???

Discussion in 'Pickup Forum' started by Antigua, Dec 24, 2019.

  1. Antigua

    Antigua Senior Stratmaster

    Messages:
    4,345
    Joined:
    Feb 28, 2014
    Location:
    in between
    They do not. It's been said on the Internet "don't use soldering guns around guitar pickups", the idea being that if a soldering gun can demagnetize an old CRT monitor, it might also demagnetize a guitar pickup. But I did an test with an old Weller soldering gun with a rather chunky transformer in it. I held the side of the gun to the top of a Strat pickup while it was activated, for about thirty seconds, and found that the pole pieces didn't demagnetize. In practice, the soldering gun would never be this close to the pickups, and it wouldn't be active for that much time.

    A member named yanyan was asking if it was true that a soldering gun could demagnetize a pickup. Of course, this could only apply to AlNiCo magnets, as ceramic magnets have a much higher coercivity. According this this site https://www.kjmagnetics.com/blog.asp?p=ceramic-remagnetization , it took a field of eight to ten thousand Gauss to magnetize a ceramic magnet, so it would take a similar strength to degauss it as well, which is achievable in between two neodymium magnets that are almost touching together. But even with AlNiCo and it's lower coercivity, a soldering gun doesn't produce a strong enough magnetic force to degauss the magnet.


    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]


    Even though the Gaussmeter shows precision in the 10's, the number bounces around a lot in real time, so the accuracy is more realistically about 5 milliteslas, but that being the case, the magnets appear to have lost no residual flux, even with the soldering gun directly over it, operating for about a total of 30 seconds.



    I hooked up a Fender Custom 54 neck pickup to an oscilloscope, and measured the voltage of the pickup at difference distances:

    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]

    The voltage output with the coil directly beside the pickup was 16 volts, which is about sixty times greater than the typical output of a Strat pickup.
     
    CFFF, EAllen, bootstrap and 2 others like this.
  2. dirocyn

    dirocyn Most Honored Senior Member

    Messages:
    5,149
    Joined:
    Jan 20, 2018
    Location:
    Murfreesboro, TN
    I always suspected the thing about soldering having any effect on the magnets was BS. Just from working a soldering iron a little bit, the tip doesn't seem to be a particularly powerful electromagnet--and it doesn't get hot enough to melt any of the components of AlNiCo.

    One issue that is real, is a soldering iron can easily burn through not only the coating on the coil wire, but the copper of the coil wire as well. Soldering around pickups is still something to be cautious about.
     
  3. Antigua

    Antigua Senior Stratmaster

    Messages:
    4,345
    Joined:
    Feb 28, 2014
    Location:
    in between
    Soldering irons work on a different principle, one that doesn't require a transformer, so there's no magnetic field to speak of. As far as heat goes, AlNiCo is very heat resilient. It's easy to find temperature tolerances for magnets in basic spec sheets since industrial equipment often gets very hot, but I haven't looked at them lately.
     
    dirocyn likes this.
  4. Class A Knob

    Class A Knob Senior Stratmaster

    Messages:
    2,082
    Joined:
    Nov 25, 2017
    Location:
    California
    I've heard the same about soldering grounds to the back of volume pots. Not the demagnetizing part, just that any more than a few seconds "ruins pots". Part of me thinks that user error is the #1 cause of component failure.