Chainsaw oil a risk to compost pile?

Somehow I only just realized that chainsaw bar oil doesn't just magically disappear, but gets flung about as you cut the wood.

I recently cut up a huge maple tree and have been using the sawdust/chippings for use as carbon in my compost pile, but now I'm freaking out that I poisoned my pile with the residue of the bar oil that might have gotten into the chippings.

How much oil could be in those chippings and how worried should I be about the pile?

Petroleum products are, generally speaking, nitrogenous; in quantities that aren't otherwise toxic to organisms, they act as fertilizer.  It's actually not uncommon in the environmental engineering world to remediate oil-contaminated soil by, essentially, spreading it out, aerating it, and seeding it with a cover crop that will consume it and (with associated soil organisms) break it down.

In a compost pile, well-balanced with other biodegradables, and in tablespoon/ounce type quantities, it will utterly vanish.

Thanks for the reassurance! So you would say that a compost made with those chips would decompose the oil and not pass toxins into edible plants (and then my family)?

Related: I put up a batch of oyster and shiitake mushroom spawn in buckets with some of these chips, and I actually boiled it first (to pasteurize). I poured off a vast amount of brown tea (which I would guess is from all the tannins in the wood) and then used the chips to (try to) grow mushrooms. I know that mushrooms in general take up toxics from substrate, but given the low quantity to begin with and the discarding of the boiling liquid, do you think there could be any remaining risk of toxicity from the oil to the finished edible product?

Also now wondering, if spent oil has that property, why don't we make commericial fertilizer from it, instead of using new fossil fuels to make fertilizer, and then having a toxic waste problem from all the leftover oil?

Most feedstock for manufactured fertiliser (the N component, anyway) is natural gas, which is used in the Haber-Bosch process.

The amount of bar and chain oil in your sawdust is less than or equal to the amount of oil you have put into/through your saw. Depending on whether you were bucking the tree where it fell, or all in one spot... the oil might be spread out over the yard, or soaked up in that one big pile of sawdust under your sawbuck.
Also discount the oil leaked out of the saw when stored.

According to https://en.wikipedia.org/wiki/Automotive_oil_recycling, spent oil is recycled into feedstock for "new" lubricants, and other stuff, by removing the additives and crud that's accumulated in it from wear/use.

Which leads me to ask... Are you using old motor oil in your chainsaw as bar and chain oil? It's not very good for that, since it lacks the additives that help it stick to the chain instead of being slung off, and it has broken down from use and contains the crud that you didn't want in your engine... now wearing on your bar and chains.
In a pinch, maybe better than NO oil?

Stihl has a vegetable oil bar and chain oil (not endorsing, have not tried, there are surely many other brands), if you are looking for an alternative to petroleum.

In this case, I cut up the tree into 16" sections, all along the length, but I used a tarp at each cut so I could gather the chips. Probably that's a lot like cutting them in one place.

I was using regular oil, but now I am getting a bottle of some "biodegradeable" product. I hope it's decent and actually better in that respect than the other stuff, because it sure costs a lot more.

@Phil: so if used motor oil is nitrogenous, why can't it be used as feedstock instead of natural gas?

@Joshua - It would involve a lot of steps to clean it and crack it to get the light high H:C fraction required. The N in the process is atmospheric and what they're after in a feedstock is hydrogen.

https://en.wikipedia.org/wiki/Haber_process

Joshua,

Used oil, right out of the engine, has a lot of combustion products and possibly a bit of fine metal in the mix.  I would never ever recommend pouring any oil on your compost, but the amounts that get flung onto any wood you want to compost is tiny indeed, to the point of being trivial.

More worrisome to me would be somehow spilling gasoline into the compost pile.  A very tiny amount of gasoline is quite toxic to most plants and microbes.  Say if you were filling up your chainsaw and accidentally spilled some on the wood you want to compost, I would save that wood for the fire pit.  Otherwise, the tiny Amount of bar oil that makes its was to the compost pile is trivial.

But congrats on wanting to get every possible containment out of your compost as you possibly can.

Eric

@Eric: thanks for the reassurance. To clarify, this is an electric chain saw, so the ONLY oil is the bar oil, and no gasoline at all.

Joshua,

Is it a battery or corded?  Not that it matters to your compost pile. I am just finding battery chainsaws pretty amazing these days.

Eric

I have one of each, actually. The battery one is amazing and portable, but heavier and limited to a 14" bar.

My corded one is lighter and has an 18" bar, which is needed for bigger trees, but isn't very portable. I'm looking for a battery+AC adapter big enough to be able to power it, and then I'll be happy.

I'd really like a 22" bar for big wood, but I don't think that exists in battery or electric.

Joshua,

I have a 12” 40v Kobalt chainsaws (in addition to a Stihl gas model).  The little battery model is my go-to pick up and use model.  It could be better but I love it as it is.

So what is your 14” model?

Eric

We've used vegetable oil-based chainsaw bar oil for many years. No stink at all, especially since the saws we use are electric, both corded and battery. I've read that some folks mix mushroom spawn into the bar oil and then can innoculate logs/stumps while cutting. Haven't tried this myself.

Eric Hanson wrote:
I have a 12” 40v Kobalt chainsaws (in addition to a Stihl gas model).  The little battery model is my go-to pick up and use model.  It could be better but I love it as it is.

It's a Makita 36V, whose batteries charge my other Makita tools, which I love, although it does make me a bit dependent on that one brand.

Larisa Walk wrote:We've used vegetable oil-based chainsaw bar oil for many years. No stink at all, especially since the saws we use are electric, both corded and battery. I've read that some folks mix mushroom spawn into the bar oil and then can innoculate logs/stumps while cutting. Haven't tried this myself.

I LOVE the mushroom spawn and I actually have some (!) so I think I'll give this a try.

What do you make of the various warnings that vegetable oil isn't thick enough, so the bars and chains wear out, the cut isn't lubricated well enough, etc?

Joshua,

Sounds like a nice little chainsaw.  I ended up getting mine simply because Lowe’s had them.  Mine is a great trim saw but I have also cut some fairly large diameter logs (10” or so).

I have occasionally contemplated going the 80v route, but I am not certain what I would do with it.


Eric

Eric Hanson wrote:
I have occasionally contemplated going the 80v route, but I am not certain what I would do with it.

A huge maple branch fell in my yard and I was able to cut about halfway from the top end, with each section getting wider to about 24" in diameter. At about 16" or 18" diameter, the 16" saw couldn't handle it. Luckily, the tree was close enough to the house that I could reach it with a very long extension cord, and the 18" bar on the corded saw, and I was able to finish cutting up the branch.

So that's one thing you might get from a bigger saw :-)

I use canola oil as bar and chain oil. Safe, non toxic, non petroleum based. I've been using it for 7 years without any problems. I buy the big container at the store.

What do you make of the various warnings that vegetable oil isn't thick enough, so the bars and chains wear out, the cut isn't lubricated well enough, etc?

I think they process the oil, maybe by cooking it a bit as it looks brownish and is thicker than cooking oil. The stuff we have is canola based and came from Bailey's, link here https://www.baileysonline.com/motion-lotion-biodegradable-bar-chain-oil-1-gallon-17070.html

That looks like a nice product, and while more expensive than the petro stuff, it's a lot cheaper than some biodegradeable products I've seen.

I wonder if used and filtered fry oil is actually better than fresh, because it's been heated. Certainly it seems thicker than before frying.