Why WD40 should be expelled from your (bonsai)toolbox


new to Mirai so hello to everyone.
As a comment to a recent question in the q&a i wanted to add some thoughts on the usage of WD40 and why i believe it has nothing to do in a bonsai toolbox.
This comes from a principle approach of using the right/proper tool for the job.

WD40 has a specific use and that is in it’s name: Water displacement. It is not an oil (yes there is app. 1/4 oil in there but still), not a contact cleaner and not a contact spray. The 3/4 of ingredients besides the oil do nothing for your potential application in bonsai except being detrimental to your health (potentially your tree’s) and the environment.
WD40 is not the aspirin of the tool world.

If you intend to clean/preserve and lubricate your tools there are specific products for this like Ballistol or camellia oil etc. which are food safe.

And please don’t use it for sharpening. The film/oil layer it creates is “thicker” than your finer grit stones so severely impeding their function as well as potentially clogging them. For sharpening there are honing fluids or you can use window cleaner if you do not want to go ahead with water only.



Just MY opinion…
WD40, MSDS says it is medium and light alaphatic… mineral oil and CO2 propellent… Perfect for light lubricating. A little light for honing, I do use it to clean the honing stones, not on a water stone…but it is safe. You apply mineral oil on your baby’s bottom and to sofen your skin… Its used to lubricate the machinery to make your chicken nuggets…
Ballistol, MSDS say, has a alkaline component(?), benzyl acetate, and a corrosion inhibited. Ok for guns, probably to clean tools, not much for lubricating; would still use a light oil on my 45 rails. I would wear plastic gloves, and maybe a chemical filter mask.
Camellia oil has a history as a sharpening oil, machinery lubricant, skin oil and for constipation. I have used it, not impressed. Gums up at low temps. Goes rancid, polimerizes. Polyphenyl antioxidents. There are better lubricants… light alaphatic mineral oil.
ALSO, we use mineral oil as a fall tree spray / drench for killing overwinter bugs on bonsai… I add sulfer spray to inhibit fungus.
Hmmm… WD40 as a tree spray…
I would avoid silicon lubricants.
Full discloser…I’m a BS chemist, worked in medical manufacturing and oil analysis. Shooting for 50 years. Bonsai-ing for 40 years. I do lose a tree now and then.
Bonsai on…


Hello Kurt,

thank you for providing your insight. The mineral oil (which is also part of the Ballistol formula iiac) in WD40 was never my concern it was the 3/4 of other ingredients. And with WD40 it is also advised to wear gloves and eye protection, or is that information not correct?
You would wear a chemical filter mask with Ballistol? Could you elaborate on the reasons as it is used as disinfectant to treat wounds and (as per your description of mineral oil) skin treatment, insect repellent and deemed food safe.

Required lubrication for a bonsai shears/pliers would be different than for machinery and weapons, or?

For the honing, what grid is that stone as not to be covered in a thicker layer of cleaning oil than its grid?

My intention was not necessarily to push any brand or single product. I just have a feeling people apply WD40 generously as a general it will fix that spray.

Everyone has their opinion.
Ballistol is designed for cleaning fouled firearms. Dissolving nitrates left from gunpowder. May be a good product for that. Safe for that use. I would still wipe it dry and apply a coat of light machine oil, petrolium based / mineral oil, for lubrication.
The msds says…, and ingredients list says… Check the hazardous section, safety section, and the TLV exposures. Compare the two products. Both are safe when used as specified.
Not for human consumption.
Popular myths, to sell product. Snake oil.
People swear by WD40 for arthritis, and cuts, too.
It was designed to coat missile cones to keep out water. Hydroscopic oil coating. It is a good light lubricant spray. Leaves a light even efficient oil coating. No hazardous ingredients listed.
I use a 5-10W machine oil for sharpening. Light petroleum based / mineral oil. Not plant based kitchen oils. The film moves around as I sharpen. It’s for floating the metal away. Not necessatily for lubrication. I would never us water on European style or Arkansas natural or manmade sharpening stones. The materials will oxidize and fall apart over time. I still have and use my grampa’s WW1 era sharpening stone.
My Japanese water stones ARE different, never use oils on them. I only use them for my sushi, kitchen, ikibana, grafting knives; and samurai short sword-- used to do bonsai and pork chops…
On a lighter note… It’s 45F here today. Still have a foot of snow. Trying to mix bonsai soil. Only have 20 gallons, need 40. Need 50 lbs of lava rock, though… Have the akadama and pumice. Picked up 25 lbs of 1/4" DE, will evaluate it… break out the microscope!
Will be interesting to see how the <20F two week long period affected my bonsai.
Bonsai on…

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Hello Kurt,

with the disagreement on the two products i feel that we are in agreement on using appropriate tools/products for the respective application.
Winter here was awol so we are again way ahead of time with everything starting to bud.
for the DE please share your evaluation. The articles /posts I read on this were discussing it as a substitute for akadama and not lava though. I only used it for one season with large uncritical yamadori so far.

I use camellia oil on my bonsai tools.


Last night I was potting several bald cypress yamadori in bus tubs. The only tool I used was a tree pruning saw. When I was done I cleaned my saw and sprayed it with Pam. I figure it’s good enough to eat, it’s a thin oil, it’ll coat the saw blade and protect it from rust, and I don’t care if it goes inedible.

Besides, my wife didn’t see me taking the Pam outside. I think I got away with it.