Canola oil just doesn't have any tachyness in it
At the temperatures most bar oils will experience in use(40-100*c), the viscosity of rapeseed is similar to bar oil - around 8-11 mPas mm
Yeah, I wouldn't use it in hotter climes.
The good news is because it isn't as tacky, it flows better. So in cooler climes, it oils rather well.
I wonder if someone could do a temperature test.
So I was reading stuff on line when I came across a load of information I thought I would share.
@RI Chevy noted that Rapeseed/Canola didn't have the tachiness that bar oil has. And, he is right. Some bar oils are rather tachy at room temperature. But cutting isn't done at room temperatures. When I was researching the tachiness of bar oil, I found the viscosity ratings of bar oils of various suppliers was nearly identical to that of rapeseed oil when rated at 40 and 100* C. When I saw that 100*C temperature, I personally thought it was a bit high for bar temps. That's boiling, after all. So I went looking for bar temps, and of course, Redbull661 delivered. He did a bunch of tests on bars not long ago. One test of note showed he could get up to nearly 100*C(212*F) at the bar tip. It's line 2, row 3 in this chart here:
http://opeforum.com/threads/guide-bar-data-and-picture-thread.1269/
Pow - he was able to get it to nearly 100*C on a 36 inch bar.
This meant I could use the ASTM D445 100*C viscosity test to compare oils on a level playing field. In other words - how well do these oils flow at 212*F - which is maybe what they will see on a chainsaw bar in use. The interesting thing is most bar oils will also have similar sheer/viscosity. They all are pretty much in the 7-15 mms range at 212*F. In fact, some oils made by Mobil, and sold under various other names, have more viscosity at 100*C than rapeseed. Mobil Chainsaw Bar oil is rated at 11mms @ 100 C, mm2/s, ASTM D445. Some other tachified mineral types are rated as high as 15. Rapeseed usually rates from 7-9 - so is actually less viscous at operating temperatures. It's not a huge difference, but it definitely implies that rapeseed is less likely to fling off the bar than some may have thought compared to tachy chainsaw bar oil under operating conditions.
Something of note is that, at 40*C(104*F), which is another metric for ASTM D445, that canola and rapeseed oil are less viscous than most bar oils - usually flowing at a rate of 35-45 vs 80-130. So, as it heats up, rapeseed very quickly becomes less viscous.
Also, the flow rate at room temperatures is interesting to note. Rapeseed flows at nearly the same at 68*F as it does at 100*F. Whereas tachified mineral oil can be quite thick at room temperatures and below, yet flow more at operating tempertures. Some of which is unusable at much below freezing. Rapeseed also freezes at -9*C or 16*F, so it isn't terribly great for below freezing use.
What does all this mean? It means that rapeseed has the potential to flow through your oilers better than bar oil at chassis temperatures, but when it heats up on the bar itself, it then becomes more tachy/less viscous. Lower volume oilers that are common on modern saws may actually work better with rapeseed than with bar oil. The best of both worlds.
A draw back in these figures imply that bar oil
might be absorbing more heat from the bar than rapeseed oil does. A couple of paragraphs down I'll include a test recently done that may go a ways to answering that question as they do test operating temperatures of mineral vs bio oil(though it isn't straight rapessed). After all, most engines do use oil for cooling as much as lubrication.
I've done a lot of testing personally. But since I do not have the resources to tests several bars at the same time with several oils, I can't really post any results from that sort of testing. What I do have is a 700 acre estate in Ireland that I manage all the forestry and trees on, and a stable of 9 saws to draw from to do so. I do not do any milling, nor do I cut often in below freezing temperatures. So, I am not your guy there. Most of the wood we cut are hardwoods - beech, oaks, ash, etc. Since 2013, we have solely used rapeseed oil. What I have been able to note for myself anecdotally is that I haven't seen any more wear from having switched to rapeseed oil, the typical stuff you buy over the counter at the grocers. I am using it on saws from 33cc up to 87cc, and bars from 14inches to 32inches. I do notice I see less oil on the trees I cut and in the environment. Something important to note, though, is the fact that rapeseed is a bit more difficult to see on a brand new clean bar vs bar oil. But on a used bar full of all manner of things, it is very easy to see how the saw is lubricating. When I do the typical test of revving the saw while watching for a mark on a clean piece of wood, the marking results are similar to mineral oil. Since Rapeseed oil is similar to your own skin oil, it supposedly causes less issues when it is trapped against your skin, or inhaled in the air when it atomizes. I can't say that typical bar oil bothered me before, so I can't say I have noticed much difference myself. But back when I used mineral oil, I smoked Lucky Strike unfilters. I have a feeling those were far worse for my health. I am now a non smoker. Rapeseed has shown in some tests to not atomize as readily as mineral at operating temperatures. It also does not vent as many chemicals as mineral when it does. But that's to be expected as rapeseed oil usually has no chemical additives. Some Boi oils are probably different, but I haven't used that since 2012. When I tested Rapeseed VS bio oil(stihl), I noticed rapeseed outperformed it for my uses, and it did it at a fraction of the cost. I suspect bio oil is better used in colder climes. Where I work it rarely hard freezes(though it will freeze every year), and rarely is above 32*C. The vast majority of the time the temps are between 40-60*F.
Some will mention the oxidizing effects or gumming of bio oils. With rapeseed, the oil itself naturally has anti-oxidants. I have stored it inside saws in weather from freezing to 32* for up to 2 years without noticing any difference in effectiveness for bar use. However, one thing I do notice it does that mineral oils don't is react with softwood or conifer sap. I haven't noticed any immediate effects
while I cut, unlike this report from europe that stated they could scientifically test for the differences between the two during the cutting conifers(
http://www.crojfe.com/site/assets/files/3945/stanovsky_83-90.pdf). But I do notice a difference if I allow the bar to sit for an extended time. I used both a small 325 16 inch bar and a 24inch Stihl laminated bar to cut several Scots pines, silver firs, laurel, and particularly a few sappy Asian Larches a few years back. Our estate has a large Larch plantation we use to make construction boards from - larch is very similar for construction to Douglas Fir as it is dimensionally stable and can be tight grained if cultivated correctly. But some can be sappy, and most of these were for firewood as they were relatively low grading trees and culls. All the saws I used had adjustable oilers set to max(a Stihl MS241, an 044 and a 288xp). After these bars sat for several years, the tips would no longer move using your hand. On the 24 inch Stihl bar, which sat for nearly 2 years in an unclimitized shed, I had to rake it against a log hard with the chain on it to unlock it. Afterwards it was fine, and it still appears in videos I make to this day. The smaller bar had much tighter tolerances and required I use some mix to loosen it up. That bar sat for 3 years. It worked fine once I sorted it.
In the end, the important thing on the estate is to keep the forestry, the land, and the saws in proper order. Considering the performance of rapeseed, keeping it around seemed like a good idea. If one considers the advantages it has as a biodegradable product, and considers the disadvantages of using mineral oils on an estate near a large river at the base of a mountain range, it really became fundamental that rapeseed oil would be our oil of choice for our chainsaws.
So there's my take on this oil schtuff.
