removing solder flux

Discussion in 'General Electronics Chat' started by petewh, Apr 29, 2016.

  1. petewh

    Thread Starter New Member

    Mar 23, 2016
    I've been making some home projects and have become concerned about removing solder flux from my breadboards. I'm considering scrubbing the flux off with isopropyl alcohol. I do wonder though would it damage the components already soldered. i.e. resistors, capacitors. In particular the electrolytic caps. When I worked in electronics over 20 years ago I didn't pick up on the deflecting processes. Can anyone weigh in?

  2. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    The only devices I would be the least bit worried about with 90% isopropyl alcohol (IPA)would be optical devices and unsealed relays and pots. On relays and pots, you may get gunk on the contacts -- depending on how clean your IPA is and technique. As for optics, it is relatively safe, but if there is a lens, you may get a smudge. You also run the risk of removing any lubricant on shafts. Are you using 90% or 70% isopropyl alcohol ? 70% IPA is less aggressive but may not be as effective at removing the flux as 90% IPA is.

    Dr.killjoy likes this.
  3. Dr.killjoy

    Well-Known Member

    Apr 28, 2013

    Also check out a good flux remover or a couple use ultrasonic bathes to clean the pcb..
    I use ipa and a soft tooth brush...
  4. MrSoftware


    Oct 29, 2013
    Denatured alcohol works well for general flux removal, and cleans the workbench well also. In addition to the warnings above, it's flammable so be careful to make sure it's all dried up before turning anything on.
  5. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    Denatured alcohol is a mixture of ethanol plus any one of several "approved" denaturant mixtures. I believe what brew is used varies by country and end purpose. Some of those mixtures contain chemicals that are more aggressive toward plastics. If it works for you, then no problem. My personal favorite is absolute alcohol + a little acetone (very roughly 3:1). Of course, acetone is aggressive toward some plastics, and I do not use that mixture when soft (e.g., styrene like) plastics are present. It works fine with nylon and the like. ABS and PVC car affected, but only very slowly. It is very quick acting and evaporates quickly without leaving little water droplets or haze behind. That is its main advantage over 90% IPA.

  6. dl324

    Distinguished Member

    Mar 30, 2015
    I use 99% IPA with a short bristle horse hair brush for most of the cleaning and finish with a commercial flux remover. Drug stores typically carry 90-91% IPA, I bought the 99% from a pharmacy associated with a hospital. Higher water content will leave more residue.
  7. takao21203

    Distinguished Member

    Apr 28, 2012
    lighter fluid.

    Liquid butane if you are desperate (dont say I didnt mention explosion risks).
    A small PCB just straight from the bottle is OK.