Canola, rapeseed, and synthetic oils

There has been a fair amount of discussion in the past few days about a “gun oil” that is suspected of being nothing more than repackaged Canola oil:

In response to a Facebook post on this topic I wrote the following comment:

We sometimes grow rapeseed and canola on the farm.

Rapeseed oil is the main component in all the “synthetic” motor oils. It can tolerate higher temperatures than the pumped from the ground. Rapeseed oil is believed to be toxic (not dramatically so, but you shouldn’t cook with it on a regular basis).

The Canola plant and seed look identical to rapeseed but the oil is much lower in erucic acid than the oil from rapeseed. The erucic acid is desired in the lubricating oils.

Canola oil is not going to be as good a high temperature lubricant as rapeseed oil. If you want to use something cheaper than the hyped up gun oils but better than common lubricants then use a Mobil One or some other synthetic motor oil.

There are some severe factual errors in that comment. It was probably 45 years ago Dad had told me Mobile 1 was made of rapeseed oil. Yesterday I discovered that was wrong. I went searching for a web page to show it was true and could not find evidence to support that claim.

I sent an email to my brother Doug asking him what the story was. He wrote back saying he had discovered the error many years ago himself. Dad was not one to exaggerate or make things up and Doug elaborated on how he might have come to this erroneous conclusion.

He elaborated quite a bit but it boiled down to the following (slightly edited to remove names):

I don’t think Dad fabricated the entire rapeseed story.  When I first started farming, I sat in several farm meetings where rapeseed and its many industrial uses was discussed.  I think much of it came from a certain plant breeder.  Dad really liked him and I did too.  He seemed like a great guy, but I have heard he was a bit of a visionary/exaggerator.  He left in the late 80s and was replaced.  The new breeder also seems like a great guy, but I have seen the results for enough years to know that most of his dreams don’t come true.  His great plans for various new crops have all fizzled over the years and he really has very little to show for his 25 years of plant breeding.

In answer to your question, I suspect much of the hype about rapeseed came from these two plant breeders and much of it was based on wishful thinking rather than reality.  I don’t have any other good explanation.

I did further research and found that while rapeseed oil has been used for lubricating oil for a long, long time it doesn’t have the extraordinary high smoke point that I had been lead to believe. When refined it is higher than many cooking oils but it’s not anything worthy of exception note.

The synthetic oils, like Mobile 1, do tolerate very high temperatures but it isn’t because they have any particular vegetable oil in them. It is because they have very particular, custom built, molecules in them that are temperature tolerant. Conventional oils, and vegetable oils, have a wide variety of molecules in them. Some of the molecules break down at lower temperatures than others. As soon as any component of the oil starts breaking down it changes everything. The viscosity can change, the lubricity can change, and the oil will cease to do its job.

I suspect that high temperature tolerance is important in firearms but I don’t know for certain. It’s not as if the oil is for the chamber and barrel of the gun. It’s for the metal on metal parts of the gun which doesn’t reach chamber and barrel temperatures.


15 thoughts on “Canola, rapeseed, and synthetic oils

  1. I suspect that the moving parts on my rifles that gets the most hot are the springs in the silencer couplings and the piston they’re attached to. I wouldn’t oil those, although there are people using high-temperature grease.

  2. What I, personally, want in a gun oil is;
    1. Corrosion protection
    2. As close to a total lack of thickening or drying over time as possible, i.e. I want it to last forever in storage.
    3. Some lubricity from minus 30 deg. F to 250 deg. F

    In that order. A well-designed gun will operate fine without lubrication, so items 1 and 2 are more important than 3. That may mean that an “oil” per se isn’t the best choice. I don’t know.

    This stuff has been studied for generations, so if we don’t know what works by now we’re pretty dumb. Looking at what works for 300,000 miles in a hot, dirty internal combustion engine would be, in my opinion, a good place to start. The requirements for a gun are a bit different, but not hugely so. The other place to look would be military testing. I would think they care, or at least a few probably have cared over the years, about what works and what doesn’t work over the wide temperature ranges and long timespans.

    • Whether or not synthetic motor oils work well in guns, I don’t know. But I would point out the glaring differences in their working conditions:
      1. Motor oil is pumped continuously onto the surfaces it’s designed to lubricate.
      2. Motor oil is filtered every time it goes through the pump.
      3. Motor oil operates inside a sealed crankcase, where the only source of contamination is piston blow-by (exhaust gases).
      4. Motor oil is designed to lubricate bearings manufactured to fit with extremely close tolerances.
      5. Engines do get hot, but the temperature is controlled by the cooling system and thermostat.
      Guns aren’t built like engines. There is “play” engineered into the fit between parts to allow them to operate when dry or dirty. They are constantly exposed to powder residue, dust, dirt and whatever else they get dropped into. In gas-operated guns, some parts are exposed to extremely hot gases with no real cooling system to keep temperatures in check. The job of a gun lubricant is quite different from the job of a motor oil.

  3. Some other angles that come to mind: not all lubrication points have the same requirements. And as a result, not all necessarily take the same lubricant. Stuff that needs to run easily but isn’t under a lot of pressure (like trigger and hammer) will like a light oil. Stuff that is under extreme pressure will be different, like the locking components. At least that’s true if they need to move under pressure when the gun is fired. The locking block of the rotary locking action in Boberg pistols comes to mind, and sure enough, that one has a specific lubricant out just for that one spot.

    If you look long enough you can find all sorts of stories, like the guy who hangs out on the Boberg forum claiming he doesn’t use the manufacturer’s guidelines but instead just soaks everything in lots of oil and “it just works great”. Better him than me…

  4. From what I’ve read, the problem is that FireClean is essentially cooking oil. It’s not a specific oil or synthetic, and it does NOT have corrosion inhibitors. Plus, there’s the fun aspect of it eventually developing deposits on surfaces when exposed to heat and oxygen.

  5. I’ve used Crisco as an anti-rust coating on carbon steel kitchen knives for many years and as the preferred anti stick coating on my favorite pancake pan. I also use it on Black Powder revolvers for sealing the front of the loaded cylinder. The same oxidized coating that builds up on the pan surface might be undesirable on the moving parts of a semi-auto firearm. In a pinch I might use it for modern firearms, but I think there would be better choices.

    • Not so much a rebuttal as a clarification. Cunningham’s criticism of motor oils is much more valid in a daily carry revolver than it is in an AR-15 (gee I wonder why that is). The detergents that make for good cleaning also act as emulsifiers which allow water to corrode the underlying steel. Since you don’t carry an AR-15 next to your skin, sweating on it all day, it’s fine as a cleaning compound for an AR. Once you discharge the rifle a few times it doesn’t matter what you lubed it with, it’s going to start drying out, and since motor oil is slightly thicker than ATF, it will take slightly longer to dry out.

      If you want to use motor oil in an maritime environment or other high humidity area, just get non-detergent motor oil. Works great for carbon removal on the bolt and BCG.

      • Another issue with motor oil is contaminants. Motor oil is designed to suspend and isolate contaminants from combustion, which then flow with the oil to the filter and are removed for the most part. This helps keep the crud from eroding engine components. There is no filtration system on a rifle so all that stuff just stays in there….

        • What you say isn’t wrong, it is just improperly applied.

          Doesn’t matter what lubrication you use, there is no filtration system on a rifle. ATF is also designed to be filtered. Also if you are using a thin film, there isn’t enough volume to do any sort of suspension as particulate size easily overpowers the volume depth of the film.

          Firearms aren’t pumping lubricants to wear points. No matter what you use, as you use the firearm the lubricants is getting used up. That is why you clean your firearm every few hundred or thousand rounds, but don’t clean your engine every few hundred or thousand piston strokes. There is a LOT more lubricrant per part in an engine than in a firearm.

          I hope that explains the need for maintenance and why engine oil is a viable choice for a rifle like the AR-15.

  6. If your into the cooking oil for protection and lubricity, you may want to try peanut oil. They use it for stir frying at high heat. Much less likely to smoke or break down than Crisco or canola oil.

  7. Don’t know anything about this particular lubricant, but a well-known Left Coast blogger noted many years ago that, because everything under the sun is “known to cause cancer by the State of California (sic)”, many PDs in that state use food-grade lubricants on their weapons. That is, they use the same stuff that McDonald’s uses to lubricate their shake machines, dishwashers, etc. It seems to work for them.

  8. “The synthetic oils, like Mobile 1, do tolerate very high temperatures but it isn’t because they have any particular vegetable oil in them. It is because they have very particular, custom built, molecules in them that are temperature tolerant.”

    Not all “synthetics” are custom made molecules. Based on a somewhat silly court decision some years ago, in terms of motor oil, synthetic is more of a marketing term.

    In a lot of the major oil brands, the only difference between the “synthetic” version and the “conventional” version is the refining process and the additive pack. Castrol, Valvoline and quite a few others use highly refined Group III oils as the base in their Synthetics. Some Mobil 1, Amsoil and a few other high dollar brands are PAO/Group IV. Even then, whatever differences there are can generally be made up with additives.

    Then there are the oddballs like Pennzoil Ultra/Platinum. They’re made from a natural gas liquefaction process which makes it a Group III oil, but because the molecules it starts with are extremely consistent and combined in a precise way, it has performance that exceeds many Group IV oils in several categories. Specifically it’s NOACK volatility numbers are VERY low, which is why I use it our Ford Edge ecoboost. Low volatility helps prevent cooking off and coking in the harsh environment of a turbocharger.

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