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Cleaning the flux: 99.8% isopropyl vs 70% isopropyl + 30% ethanol mix?

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    Cleaning the flux: 99.8% isopropyl vs 70% isopropyl + 30% ethanol mix?

    Hi!

    I would like to know which one is better for cleaning up soldering flux from pcb after soldering?
    One option is 99.8% isopropyl alcohol
    Other option is 70% isopropyl and 30% ethanol mixed together solution.

    And also what would be the process? Do I just put it on pcb and let it evaporate or should I wash this off once it absorbed all the flux?

    I also read that isopropyl is bad for pcb, but I am not sure what to think of it or what other alternative to use in that case?

    #2
    Re: Cleaning the flux: 99.8% isopropyl vs 70% isopropyl + 30% ethanol mix?

    ipa is harmess.
    but you need to wash the flux off with it - not just melt it into a pool

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      #3
      Re: Cleaning the flux: 99.8% isopropyl vs 70% isopropyl + 30% ethanol mix?

      ^correct

      Acetone is the one to avoid, or at least use sparingly if there is no other alternative, as it can damage the PCB coating.

      Comment


        #4
        Re: Cleaning the flux: 99.8% isopropyl vs 70% isopropyl + 30% ethanol mix?

        acetone will also remove the print / paint from components leaving you with a mystery-pcb!!

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          #5
          Re: Cleaning the flux: 99.8% isopropyl vs 70% isopropyl + 30% ethanol mix?

          https://www.techspray.com/cleaning-e...propyl-alcohol
          https://www.digikey.com/en/maker/blogs/cleaning-pcbs
          Never stop learning
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          http://www.badcaps.net/forum/showthr...956#post305956

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            #6
            Re: Cleaning the flux: 99.8% isopropyl vs 70% isopropyl + 30% ethanol mix?

            Toothbrush or cotton bud. Dip either in your isopropyl then scrub the area with flux. I like to follow up with a cut up tshirt put over the wet area then use toothbrush over shirt to soak up the flux/isoprop solution.

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              #7
              Re: Cleaning the flux: 99.8% isopropyl vs 70% isopropyl + 30% ethanol mix?

              Thanks for info. Now I know not to use acetone. but how is that mixture of 70% isopropyl and 30% ethanol that I mentioned in first post compared to 99.8% isopropyl? is there any difference?

              Comment


                #8
                Re: Cleaning the flux: 99.8% isopropyl vs 70% isopropyl + 30% ethanol mix?

                Originally posted by LearningToRepair View Post
                Thanks for info. Now I know not to use acetone. but how is that mixture of 70% isopropyl and 30% ethanol that I mentioned in first post compared to 99.8% isopropyl? is there any difference?
                A quick search online suggests Ethanol is also safe, and sometimes used in place of IPA (Isopropyl Alcohol, not the beer ) due to being cheaper.

                I've also used and seen others use "medical-grade" rubbing alcohol (~70% IPA and 30% water) without issues for cleaning electronics. So if that worked, then the mixture you suggest above will probably work even better - maybe just as well or nearly so as 99+ % IPA.
                Last edited by momaka; 07-25-2020, 11:56 AM.

                Comment


                  #9
                  Re: Cleaning the flux: 99.8% isopropyl vs 70% isopropyl + 30% ethanol mix?

                  Depends on the flux you're using. If you're using natural rosin as flux, you need isopropanol as the solvent to clean it, 70%-99% doesn't matter.

                  If you're using a water soluble flux, you should use...guess what? Water.

                  Guess what also will clean up water soluble flux? 70% isopropanol, though not perfect, it has 30% water that will clean water soluble flux too.

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