While adding a new lead to a pcb board by soldering iron touched one of the electrolytic Capacitors, and melted the plastic casing of the Cap.

Should I replace this Cap?

  • \$\begingroup\$ do some research into the construction of a capacitor. a capacitor is highly dependent on the internal dielectric insulating properties of wax paper or other delicate materials. melting these delicate maerials could short out the cap. the plates of a tubulur cap are right next to each other and. only kept from shorting by this material. \$\endgroup\$ Oct 5, 2013 at 18:19
  • \$\begingroup\$ A picture would help. If it's not too badly melted, it should be fine. \$\endgroup\$
    – markrages
    Oct 5, 2013 at 20:38

1 Answer 1


PROBABLY OK but cannot be sure.
If this is mission critical / life support / you really care, then replace it.
If it failing is no big deal then leave it and see.
In many cases it will be OK.

A modern "electrolytic capacitor" (usually an Aluminum wet electrolytic capacitor)is built inside an Aluminum can which serves as the negative connection. The outer plastic layer has no part in the operation of the actual capacitor - it serves as a means of insulating the can from accidental electrical contact and provides a convenient place to write information on. If you destroy the plastic that does not affect the capacitor in any way BUT heating the metal can will transfer some heat into the interior. A mild 'touch' is liable to have little or no ill effect but any strong localised heating may boil local electrolyte or cause damage through expansion of the material.

Experience suggests that there is enough heat-sinking in the can to allow the occasional light touch with no perceived ill effects in normal use. BUT ANY touch that causes significant heating MAY cause problems months or years later. If you care or it matters, and it was not an expensive capacitor, replace it. If not replaced, keep a small mental note for the future - and learn to solder even more carefully :-).

  • 2
    \$\begingroup\$ Agreed, but I would add that you should just replace the capacitor. Most components are cheap enough that it is cheaper to replace it than for you to spend time debugging why your circuit just doesn't work quite right. \$\endgroup\$
    – Napthali
    Oct 5, 2013 at 15:51

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