WD40 & cast-iron

The_Apprentice

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Well I don't know.

I've read in many places that one should spray WD40 over their new mini-lathe (and adding oil), including on the cast-iron bits....


And then elsewhere on other sites I will read that putting WD40 on any cast-iron is a definite no-no... as though it will cause some harm to the metal.

I am a bit confused on this, and curious what the majority has to say here.

Thanks in advance.
 
I have often used WD40 on my tools, including cast iron, old and new, and have never seen
any negative reactions to the metal. This is the first and only time I have ever heard this.
Where do you hear that from?
 
Well I don't know.

I've read in many places that one should spray WD40 over their new mini-lathe (and adding oil), including on the cast-iron bits....


And then elsewhere on other sites I will read that putting WD40 on any cast-iron is a definite no-no... as though it will cause some harm to the metal.

I am a bit confused on this, and curious what the majority has to say here.

Thanks in advance.
I don't think the problem is that you shouldn't use WD-40 at all but that you shouldn't use it expecting it to protect. WD-40 is not a protectant and will allow your equipment to rust.
 
WD40 will not hurt cast iron, but will not do much to help it, either. WD40 is mostly kerosene or a very similar aromatic hydrocarbon. WD stands for "water displacing." That is what WD40 was designed for, not for lubrication, not for corrosion protection. WD40 frees up stuck mechanisms short term, but gums them up long term.
 
You should see what it does to a beautifully blued Belgian Browning shotgun barrel , left in a safe sprayed down with wd40 . When it came to me to clean up I was about sick , treat a high grade gun with the cheapest crap ever. I got it back to like new but it and he was lucky. One reason ill never have in my gun box.
 
I use spray can of Rust Check or Krown, which ever is near the hand at the time. Spread with an oily cloth. They will not evaporate away leaving a brown varnish like residue that WD40 does.
Pierre
 
I learned my lesson many years ago the hard way. Sprayed a nice shiny piece of metal with WD40 thinking it would help keep the rust away. Maybe it does for the first few weeks/months. But after that it attracted the rust. It looked like I left it out in the weather for years to rust. Never again, I only use WD40 now to remove black pen marks.
 
There are lots of good alternatives ... Boeshield T-9, Fluid Film (if you don't mind the sheep-like smell), and Frog Lube.
 
IMO leaving a tool out in the weather is about the same as treating it with WD40. WD40 has to be the most overblown hype ever in the tool, handyman dept. If you want something not to rust keep it clean, dry and avoid large temperature and humidity swings. Hi humidity is not a problem if tool is clean and air is kept moving. I know now some one is going to tell us how WD40 gives them the best woodies, mixes great drinks, and makes everything work perfect...... same guys use bar oil for way oil.
 
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