WD-40 as contact cleaner...???

Discussion in 'General Electronics Chat' started by cazksboy, Mar 31, 2010.

  1. cazksboy

    Thread Starter Active Member

    Nov 9, 2009
    A long time ago a friend had told me about using WD-40 as a contact cleaner in 117-volt on-off switches in machinery. He said that he knew that carbon tet was the best but since it got outlawed he just used WD-40 followed by an isopropyl alcohol rinse.

    Thoughts anyone???
  2. retched

    AAC Fanatic!

    Dec 5, 2009
    It works very well. It is used in automotive shops for contact cleaning every day. A few mechanics with a fatter wallet will use brake cleaner when the rest of the device is non reactive. I have yet to spray a board down with it, but followed with an isopropyl spray-down, seems to be a winner.
  3. KMoffett

    AAC Fanatic!

    Dec 19, 2007
  4. someonesdad

    Senior Member

    Jul 7, 2009
    If you read the MSDS, WD-40 is about half kerosene/naphtha and about a quarter mineral oil by weight. I can't see why anyone would want to put mineral oil on electronics, but if you're going to follow with e.g. IPA, why bother in the first place? Just use the IPA by itself or squirt some lighter fluid on it. Be aware that a lot of IPA has water in it. A better choice would be denatured ethanol without water if you can find it at your drug store.
  5. rjenkins

    AAC Fanatic!

    Nov 6, 2005
    WD-40 (or 3-in-1 oil) work extremely well as contact cleaner.

    The problem is, if used in environments where there could be dust, the oil residue causes dist to stick and creates more problems that you started with.

    You are better off trying a zero-residue solvent first, and keep the libricant types in reserve as you will need even more solvent to remove the excess.

    In dust-free environments, the oil on the contact surfaces is actually a benefit, as it prevents oxidisation and reduces wear.

    (But do not ever use a silicon based lubricant on contacts).
  6. jpanhalt


    Jan 18, 2008
    Be aware that all denatured alcohol is not the same. There are many approved formulations for it. Some of the common formulations contain acetone, MEK, or other solvents that can attack certain plastics (like styrenes, ABS) (See:http://en.wikipedia.org/wiki/Denatured_alcohol for a brief listing).

    In most cases, you will probably be OK, but it is worth a test to be sure nothing on the PCB or part will be damaged, like a face plate.

  7. shortbus

    AAC Fanatic!

    Sep 30, 2009
    I used WD-40 to clean a volume control pot once, /i was in a boom box at work. Never again, it melted the plastic and caused the resistive element in the pot to come loose. Good thing it wasn't a expensive one.
  8. eray

    New Member

    Mar 31, 2010
    i have used to clean every kind of contact and switch with wd-40. it works great and no problems yet.
  9. cazksboy

    Thread Starter Active Member

    Nov 9, 2009
    To be clear, IPA does not have water in it. The IPA we keep at my employer is reagent grade, 99% isoproply alchohol. I think you're thinking of rubbing alcohol, which is 30% alcohol.

    Thank you all for the replies!
  10. flat5

    Active Member

    Nov 13, 2008
  11. someonesdad

    Senior Member

    Jul 7, 2009
    That's true for industrial chemicals, but often isopropyl purchased at the drug store will have significant amounts of water. My caution was mainly to make sure people read the labels to know what they're using.

    AFAIK, most contact cleaners are some type of solvent that readily evaporates (anhydrous IPA is apparently popular). Be aware of this, both for the possibility of the evaporating fumes as well as the danger of dissolving/softening/damaging something nearby. My personal favorite was 1,1,1 tricholoroethane, but that's been a banned chemical for many years.