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I'm comparing it to mineral spirits essentially. Are they the same on wood? Mineral spirits seems to strip off any finishing on wood, will WD-40 do the same?

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    Even if it strips finishing, it probably leaves a lot of residue as well since it is also used as lubrication.
    – Allman
    Feb 7 '17 at 15:38
  • Although many people mistakenly use WD-40 as a lubricant is NOT a lubricant, it is a penetrant. I would never want to put it on a nice piece of wood.
    – Alaska Man
    Feb 10 '17 at 10:20
  • NO,NO,NO. That is the worst thing yhou can use on wood. Feb 10 '17 at 18:34
  • @Alaskaman WD-40 is not a single-use liquid. It can, and is, used as a light lubricant. This works because once the volatile component (Stoddard solvent) evaporates it leaves the heavier part (mineral oil and petroleum jelly) behind. Granted it's not the ideal way to lubricate many things, but it's not the world's best penetrant or rust inhibitor either and that doesn't stop it being used heavily for both purposes.
    – Graphus
    Feb 11 '17 at 10:05
  • @SparkyVaughn Oh I don't know, wouldn't straight Vaseline be worse? How about used motor oil? ;-)
    – Graphus
    Feb 11 '17 at 10:06
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WD-40 is not equivalent to mineral spirits at all. Mineral spirits should normally be just naptha, where WD-40 has multiple different petroleum base oils, as well as a few other ingredients.

Their compositions can be seen in the material safety data sheets:

WD-40 MSDS

Mineral Spirits MSDS

Edit: As Allman and Keshlam say, the short answer is it will leave a residue that will be undesirable and most likely hazardous to a new finish.

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    In other words, not only is it likely to damage a finish, it may leave enough long-lasting residue to make refinishing ... Interesting.
    – keshlam
    Feb 7 '17 at 15:45
  • In California, at least, "mineral spirits" is no longer naptha. Do be careful, the current CA formulations can behave quite differently than naptha, especially on nitrocellulose finishes.
    – bpedit
    Feb 7 '17 at 18:15
  • @bpedit ??? Is it sold literally with "mineral spirits" on the label or are there qualifiers?:
    – Graphus
    Feb 7 '17 at 18:16
  • @Graphus. Sold as "mineral spirits" although a current can in my possession does also display "odorless" but in a smaller, different font detached from the main title.
    – bpedit
    Feb 7 '17 at 18:23
  • That is interesting @bpedit . The MSDS I linked above says it is for 'odorless mineral spirits'. I wonder if California just has their own definition of this? Feb 7 '17 at 18:26
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Is it OK to use WD-40 to clean wood?

I think this is an it depends more than a clear no. I wouldn't ever use it on bare wood, but then I don't think people should use mineral oil on wooden products and that is widely done these days.

I have actually read of WD-40 being used as a finish of sorts for bare wood fairly recently on a blog somewhere, either for refinishing tool handles after the remains of the original finish had been sanded off or to finish new handles.

The one case I think WD-40 would be acceptable to use on wood would be to clean and polish finished wood that was very grimy or greasy, essentially using it as a ghetto furniture polish.

There's something else I think I should cover and that's this:

Mineral spirits seems to strip off any finishing on wood

Actually mineral spirits (UK: white spirit) won't dissolve most finishes once they are dry/cured. Spirit and waterbased stains would be unaffected, it doesn't interact with most varnish (especially modern ones made using synthetic resins), it has zero effect on shellac, most lacquers and all the waterbased finishes I can think of.

It will strip away wax however, because mineral spirits is a solvent for wax. But wax is rarely used as a standalone finish (for good reason, it provides little real protection by itself).

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  • Yes, let me run home and rub down my hammer and axe handles with WD-40, that sounds like a fantastic idea! /sarcasm Seriously, though, what tool handle to you want covered with a lubricant? (Technically, the "WD" stands for "Water Displacement" so it's hydrophobic, but it is incredibly slippery stuff...)
    – FreeMan
    Feb 7 '17 at 20:58
  • @FreeMan I think the idea is that it's applied and the excess is rubbed off, like with most oils used in finishing. If so the wood wouldn't be actively greasy any more than it is after BLO is applied. But like I said I wouldn't use it!
    – Graphus
    Feb 7 '17 at 22:27
  • Mineral oil is also slippery and non drying, but I still use it on all my gardening tools once a year and the wood sucks it in so greedily that they're not even a tiny bit slippery 10 seconds after application. If your tools are bone dry and you don't have oil on hand, WD40 is fine. It's just paint thinner and fish oil. Mar 9 '17 at 23:19
  • @PaulNardini No fish oil in WD-40 Paul, that one's about as old as the story that Elmer's is made from milk ^_^
    – Graphus
    Mar 10 '17 at 8:26
  • It's petroleum based now. True. Mar 11 '17 at 12:22
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Get a quality spray bottle, fill with Luke warm water, add a couple teaspoons of Dawn.

You now have an amazing cleaner / bug killer / pre wash dish spritzer / insecticidal soap for plants.

WD 40 is paint thinner and fish oil. Not bad for some things, but it will act as a bad finish more than a cleanser on wood.

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  • I ended up using Murphy's Oil Soap Wood Cleaner and it worked pretty well.
    – strider
    Mar 10 '17 at 15:39

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