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    Silly question: destroyed a capacitor by solder iron?

    Well, it's true that eventually if you heat the pins of an electrolytic capacitor with a solder iron, the bung will melt and destroy the capacitor, but have anyone actually destroyed a capacitor by overheating a capacitor such that the electrolyte seeps out? Is it possible?

    Any solder/desolder mishap stories to share?

    #2
    Re: Silly question: destroyed a capacitor by solder iron?

    done that while trying to desolder some from modern pcb's that have very-high melt point solder.

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      #3
      Re: Silly question: destroyed a capacitor by solder iron?

      Interesting, thought the wires were somewhat "resistive" (takes a while to heat up one end and have the heat conduct to the other) that it'd take quite a bit to cause the electrolyte to boil?

      Comment


        #4
        Re: Silly question: destroyed a capacitor by solder iron?

        the wires are copper, better than aluminium and second only to silver on the thermal conduction scale!

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          #5
          Re: Silly question: destroyed a capacitor by solder iron?

          Actually thought most caps' leads were STEEL?
          Check a magnet!

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            #6
            Re: Silly question: destroyed a capacitor by solder iron?

            that's probably tin plating, although they used to be aluminium.
            (still with tin plating)

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              #7
              Re: Silly question: destroyed a capacitor by solder iron?

              It would take a very long time to heat the capacitor before you destroy it: probably upwards of a few minutes where the capacitor body is above 200C. (After all, even electrolytic caps can withstand the heat of a nearby BGA chip being soldered/desoldered).

              Now, I've destroyed a number of Panasonic caps the same way like stj - basically the rubber bung started melting, and then the capacitor lead(s) started pulling out and messed up the capacitor internally. One managed to leak a little bit as well. Panasonic seems to use softer rubber bungs that melt at a lower temperature. Their advantage is, however, that the rubber seal withstands pressure better. So be careful when desoldering Panasonic caps.

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                #8
                Re: Silly question: destroyed a capacitor by solder iron?

                I was wondering what happened to that KMG (105°C) Chemicon capacitor. It took a while before I finally could get that capacitor out but I wasn't heating it for like 5 minutes straight (had to add solder and keep both terminals hot while jiggling before I could get it out.) There was more or less dried electrolyte all over the bottom and on the board indicating that it clearly leaked. I didn't hear any boiling/sizzling which probably vindicates me from damaging it during removal.

                I always try to remove capacitors carefully so I can test them and replace them if they test good OOC. Alas this one was clearly bad OOC as well as in situ so hence the jury rigged 'replacement'.

                I do wonder how hot it got for that capacitor to spill its guts, and surprisingly the other low voltage secondary caps look/test OK. Since the PSU works with the jury rigged capacitor, this ascertains the failure point and I now have to assume that the damage was done before I removed the capacitor.

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                  #9
                  Re: Silly question: destroyed a capacitor by solder iron?

                  Think i've done it once or twice, but not due to heat, rather to pulling too hard on one of the leads.
                  Originally posted by PeteS in CA
                  Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
                  A working TV? How boring!

                  Comment


                    #10
                    Re: Silly question: destroyed a capacitor by solder iron?

                    Originally posted by eccerr0r View Post
                    Well, it's true that eventually if you heat the pins of an electrolytic capacitor with a solder iron, the bung will melt and destroy the capacitor, but have anyone actually destroyed a capacitor by overheating a capacitor such that the electrolyte seeps out? Is it possible?

                    Any solder/desolder mishap stories to share?
                    As funny as it sounds, I had that happen to a KZE out of a P4P800 SE motherboard.

                    Needless to say I used something else to replace it.
                    Main rig:
                    Gigabyte B75M-D3H
                    Core i5-3470 3.60GHz
                    Gigabyte Geforce GTX650 1GB GDDR5
                    16GB DDR3-1600
                    Samsung SH-224AB DVD-RW
                    FSP Bluestorm II 500W (recapped)
                    120GB ADATA + 2x Seagate Barracuda ES.2 ST31000340NS 1TB
                    Delux MG760 case

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                      #11
                      Re: Silly question: destroyed a capacitor by solder iron?

                      The other thing is that I thought that capacitor leads were welded to the foil internally, yet I've had pins pull out of the foil... is it due to the soldering or perhaps it was damaged well before then?

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                        #12
                        Re: Silly question: destroyed a capacitor by solder iron?

                        I have had it were the pins have come out on a no name brand caps

                        I have not had any pins come on any KZE & KY I use them all the time
                        9 PC LCD Monitor
                        6 LCD Flat Screen TV
                        30 Desk Top Switching Power Supply
                        10 Battery Charger Switching Power Supply for Power Tool
                        6 18v Lithium Battery Power Boards for Tool Battery Packs
                        1 XBox 360 Switching Power Supply and M Board
                        25 Servo Drives 220/460 3 Phase
                        6 De-soldering Station Switching Power Supply 1 Power Supply
                        1 Dell Mother Board
                        15 Computer Power Supply
                        1 HP Printer Supply & Control Board * lighting finished it *


                        These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                        1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                        2 Hem Saw Computer Stack Board

                        All of these had CAPs POOF
                        All of the mosfet that are taken out by bad caps

                        Comment


                          #13
                          Re: Silly question: destroyed a capacitor by solder iron?

                          Originally posted by eccerr0r View Post
                          The other thing is that I thought that capacitor leads were welded to the foil internally, yet I've had pins pull out of the foil... is it due to the soldering or perhaps it was damaged well before then?
                          They are.
                          But the foil is not what holds the capacitor leads from coming out - that's the bung's job. Think about what happens if you take a needle or two and put it through a piece of aluminum foil and then slide it down - it will easily tear, even if you have 10 of those needles. Same happens inside a capacitor when the bung is severely softened from heat during soldering/desoldering and you pull on a lead.

                          So that's why it's always a good idea to make sure the solder has completely melted before trying to pull a cap out. Otherwise you exert more force on the (heated) bung, and that can caused a capacitor lead to pull.

                          Like I mentioned above, I've had that happen more often with Panasonic that any other brand. In particular, I destroyed a number of Panasonic FL caps from when recapping a batch of P4SD motherboards. And this mainly happened when I started recapping those motherboards only with a 35W soldering iron, which clearly wasn't big enough for the task. I then switched to my 75W station, and no longer had that problem.

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