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de-capping (prior to re-capping)?

Discussion in 'd.i.y.' started by bugbear, Sep 19, 2022 at 8:55 AM.

  1. bugbear

    bugbear pfm Member

    Assuming I don't have a fancy solder rework station (because I don't :)), what's the "approved" way to desolder a radial capacitor?

    Removing a resistor, or axial capacitor, is super easy because you can easily desolder one end, and lift it clear, then do the other end.

    But a radial cap won't come out that way.

    (I guess small signal transistors are even worse).

    Tips, links, videos all welcome.
  2. mansr

    mansr Objectionist

    Heat one side and tilt the capacitor to pull the lead as far as it will go, then switch to the other side. Reapeat until it comes free.
  3. TalYWaun

    TalYWaun pfm Member

    Place a piece of desoldering wick/solid copper wire so that it spans both pads, add solder and both pads will melt at the same time. Adding a bit of fresh solder to the pads helps the old solder melt quicker.
  4. Puggie

    Puggie pfm Member

    Cut down the middle of the can with fat sidecutters, then desolder the legs individually as you would other components as you described. You can also cut the can off leaving a couple of mm at the bottom and then pic that off, just leaving the legs. Very destructive, but you didn't want the old car anyway.
  5. david ellwood

    david ellwood Kirabosi Kognoscente

    If the pin spacing is narrow then use a wide nib iron and heat both pads at the same time, if wide spaced then use tilt method.
  6. mansr

    mansr Objectionist

    Or use two soldering irons. Hold them like chopsticks with one hand while pulling the capacitor with the other.
    337alant likes this.
  7. miktec

    miktec unissued

    Most of the above will do the trick - I use the technique for radials described by mansr in the first reply ;)

    But just to add that it's worth removing as much of the old solder as you can before removing anything. A solder sucker and wick work well for this.
    One problem I get sometimes if I don't take the time to do this is that the hole floods shut with solder as I pull the component wire.
    Can be a risky business trying to free it afterwards with a chance of damaging the track (which I have done in the past ...)

    Another key tool is long-nose pliers ... saves burnt fingers ;)
  8. Barrymagrec

    Barrymagrec pfm Member

    The ultimate rebuttal of "intelligent design" is the fact that we don`t have three hands for this kind of stuff.
  9. gavreid

    gavreid pfm Member

    I used to build lasers and laser amplifiers and I always felt that a short arm coming from the middle of the forehead would be a big advantage, especially for holding an infrared viewer - but it would look a wee bit silly :)
  10. Gervais Cote

    Gervais Cote Predator

    miktec likes this.
  11. Puggie

    Puggie pfm Member

    Hot air can be good too if you have a hot air gun with a fine end. These are amazing for the money when they are in stock:

    Available in 110 and 230v but supplies are sporadic. Variable temperature and airflow with a fine tip. I find it good for heatshrink desoldering chips and multi lead components and soldering small SMT stuff with the pads under the chip. Very handy, steinhel(sp) do a proper industrial version for about £250 from memory.
  12. mansr

    mansr Objectionist

    With plated through holes, removing too much solder can make it difficult to apply enough heat quickly.

    Iron on one side, solder sucker on the other tends to work.
    a.palfreyman likes this.
  13. Tony L

    Tony L Administrator

    Buy this lovely Japanese Engineer brand desoldering pump. Just trust me. It is brilliant. It has a remarkably strong suction and because the end is silicone tubing you can hold the iron right against it without melting or damaging it. I also have a proper Hakko FR301 desoldering gun (crazy expensive now post Brexit (I paid £300, and that felt like a lot!)) but if I’m just doing a couple of caps, resistors etc I use the little Engineer sucker. It really is remarkably good. Amusing to see just how far they’ve spread around the YouTube vintage computer and video game community, nearly everyone uses one now!
  14. sq225917

    sq225917 Bit of this, bit of that

    Use paste flux, the none clean up type, but do clean it afterwards. Mansr's rocking method is my preferred version. But if there's space I like to use side cutters to clip the can off ASAP as it just acts as a huge heatsink, more an issue with big psu caps than small voltage/ capacitance types.

    Simon, currently removing 16 caps and 60 transistors from a bad diy build.
  15. mansr

    mansr Objectionist

    Be careful with that one. It can easily poke you in the eye with considerable force. I prefer the ones with a guard to prevent this.
  16. Barrymagrec

    Barrymagrec pfm Member

    I once saw someone at Broadcasting House smash the bulb in his benchlight with a similar device.
  17. miktec

    miktec unissued

    Works occasionally but bit too hit and miss IME ..... in dire need a Dremel comes in handy to re-bore.
    Last edited: Sep 19, 2022 at 2:58 PM
  18. Barrymagrec

    Barrymagrec pfm Member

    Careful with that, if you take out the through plating you can be in trouble.
  19. Puggie

    Puggie pfm Member

    To clear holes of solder, flood them with fresh solder, then vac pump or braid them off. For stuff with a ground plain that is wicking all your heat away preventing you clearing the hole, I heat the pad with an iron (from the ground side) then poke through a bit of 0.5mm stainless wire. The solder will not stick the the stainless and you don't risk damage to the through hole plating. 0.6mm pcb drill is a last resort to clear holes, multi layer pcbs with mid layer ground plains are the worst.
    miktec likes this.
  20. miktec

    miktec unissued

    I have stainless dressmaking pins reserved for the occasion ;)

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