This report covers:
- Many different reports
- CO2 oiling
- Avenge-X
- A leak
- What is happening?
- High-flashpoint silicone oil
- How to oil
- Maintenance
- AirForce
- Too many o-rings
- Summary
Today I hope to put bits and pieces of many reports on oiling pneumatic airguns into a single place.
In a comment to Part 2 of A fresh look at the Umarex Notos reader Rivegauche quoted me, “And with what we have recently learned about oiling the seals and o-rings, I made sure to put many drops of silicone oil into the gun during charging.”
He then said, “I’m a Notos owner and this is the first time I’ve come across this idea. Tom, or anyone, can you please share a link where I can learn more about lubricating fill probes? Thanks.”
Many different reports
When I thought about his question I realized that I might be the only person who knew everything I have been trying to say about oiling pneumatic airguns. I would write a part of it in one report and another part in a different report and in the end I may have written dozens of reports on oiling — each with one or two important bits of information. But I was the only one who knew them all. I will try to clear that up today.
CO2 oiling
Years ago I wrote many reports on oiling CO2 guns. We discovered together that o-rings need to be oiled to keep sealing. The same is true for pneumatics.
Avenge-X
Many months ago while testing my Air Venturi Avenge-X rifle I noticed that it was leaking slowly. The leak was so slow that I was able to proceed with the tests, but something needed to be done. One of the readers recommended oiling the air reservoir with high-flashpoint silicone oil and I immediately did so. Nothing changed.
A leak
In Part Fourteen of the Avenge-X report I said this, “After the last report on the Avenge-X in early July I set it aside for a while to cover other airgun subjects. When I returned to it in late August I saw there was 2800 psi in the reservoir. Since I didn’t remember what I had done in the previous test, I just filled the rifle again to prepare for tuning the powerplant the next morning. But when I looked at the air gauge the next morning I saw the rifle had leaked down from 3500 psi to 2800 psi overnight. So I filled it again and this time I heard air hissing out under the fill pressure gauge.”
I won’t go into all that I did, but over the next two months I disassembled several precharged pneumatics (PCP) because all of them were leaking. In fact the only PCPs I own that don’t leak are those made by AirForce Airguns. They hold air for decades. But almost all of the other PCPs leak. I rebuilt my Crosman Challenger target rifle and reported on it. I need to rebuild my Avenge-X and Avenger and Benjamin Marauder and BSA R10. My Crosman MAR17 leaked slightly, but I oiled it and it does seem to be holding.
What is happening?
The o-rings in PCPs need oil for two reasons. First — the oil acts as a barrier around the edges of the o-rings to seal the minuscule imperfections in the surfaces they seal, much like the piston rings of an internal combustion engine. And second — the oil helps preserve the freshness of the o-ring itself. For this reason it is advisable to oil the o-rings with high flashpoint silicone oil.
High-flashpoint silicone oil
Oxygen is extremely flammable. The oxygen in air becomes more likely to burn rapidly when the air pressure increases. Rapid burning or oxidation is better known by another name — an explosion. Your PCPs are subject to experience rapid oxidation when the pressure rises, such as when they are being filled with air. All they need for this to happen is fuel. Petroleum products like oil provide the fuel.
But there are silicone (non-petroleum) oils that have a high flashpoint. That means they don’t oxidize at the temperatures at which our PCPs operate. These oils will not explode under the pressures we use.
Super-Lube is a high-flashpoint silicone oil.
Airgunners have been using high-flashpoint silicone oils for decades for oiling the piston seals of their spring-piston airguns. Chances are many of you will have what’s shown below or something like it already. And the thin application needle that comes with some oils like this one is a plus.
RWS Chamber Lube is even more flexible for airgunners because the thin application needle helps us apply it where needed.
How to oil
How do you oil the o-rings and seals of a PCP? You do it the same way you have been oiling your CO2 airguns when installing a new CO2 capsule. Put the oil in the air hole of the fitting before you fill with air. The air pressure will blow the oil into the reservoir as the gun is filled. You can only get a couple drops of oil in this way, so oil the gun at every fill. You cannot put too much oil into the airgun this way. If there is excess, it will be blown out of the valve as the gun is fired.
1
Drop the high-flashpoint silicone oil into the opening of the air intake (arrow points to the opening of a Foster fitting).
This is one reason why I like Foster fittings over fill probes and the Air Arms fill adaptor — because with the Foster the oil goes straight in.
The Air Arms fill adaptor.
Maintenance
I recently showed you that Skout airguns recommends disassembly and inspection of their PCP guns annually for those who shoot them a lot. In this service the o-rings are being checked and maintained or replaced if necessary. The oiling is a regular part of their maintenance. That is for shooters who shoot 30,000 pellets and more per year. If you only shoot a few thousand pellets per year from that airgun and you oil as described, your PCP should stay sealed for years.
AirForce
I mentioned that AirForce airguns stay sealed for decades without oiling. I have now begun to oil mine as I fill them but when I worked there I saw thousands of them and never saw a leaker. I repaired all the airguns that were returned for maintenance and in three years I never once saw a leaker. My exposure to PCPs was sort of colored by that experience.
AirForce reservoirs have just a single o-ring sealing them — or at least the older ones I worked on did. I assembled all of them — thousands for both the UK and the US, and I coated that o-ring with Dow Corning silicone grease. I suppose that stuff will eventually fail, but it will probably take decades.
Too many o-rings
Other PCPs have a dozen o-rings or more. Those guns need the type of care described in this report. Remember, each o-ring needs oil.
Summary
There you go, Rivegauche. That is why your Notos needs to be oiled and also how to do it. I hope this has helped.
B.B.,
A great service you have done for PCP owners everywhere.
I do have a question and an observation.
Have any of your DAQs leaked?
I have nine or so of them and only one has leaked and that was the Foster fill fitting O-Ring that failed very likely caused by me charging too quickly from a 4,500 PSI carbon fiber cylinder; the O-Ring showed signs of having been cooked.
shootski
shootski,
OK, get a cup of coffee because here we go.
Dennis very likely manufactured to a higher standard than most manufacturers, not just airgun manufacturers. He also very likely used higher quality materials in his manufacturing.
Now, why RRHFWA will not buy from Wang Po Industries if he can help it. Quality. That is it. When I was a working stiff in the polymer manufacturing equipment industry, we had customers in China. They would not buy equipment from fellow Chinese companies.
We had customers who would not buy our equipment if any component was made in China. We were required to provide documentation for every single nut and bolt used on the equipment they purchased. Yes, they paid out the wazoo for such but were willing to do such. These customers had learned that they could either pay up front or in the rears.
I am not saying that Wang Po Industries has not learned anything along the way. It is about time. Not too long ago our host would not buy an airgun made by one of Uncle Xi’s cohorts. Now it seems his place is full of them and he his dancing with his pom poms. Now that is a scary picture.
Do not get me wrong. I have been sorely tempted to give in and have something from Wang Po Industries come live here. The truth is, many if not all of the newer TCFKAC airguns have their parts made over there. All of those “gals” have found a new place to live. I am just not impressed yet. Being an old, fat, baldheaded geezer, I very likely never will be. Hey, I am dancing with airguns that are over one hundred years old.
I do understand economics. I have to. I am retired and really have to watch where every penny goes. I can either buy something of quality that with proper maintenance will last the rest of my time on this Earth, or I can throw what little money I have after something that may or may not last until then.
I have three AirForce air rifles living here at RRHFWA right now. There is a fourth one that I would not mind too much if it was to move back in. Otherwise, most of the “gals” living here are of the “old gal” variety. Would I welcome a DAQ into my humble abode? You betcha, if I had the money. I like top shelf stuff.
So, what does all of this boil down to? You young whipper snappers had better buy some good quality silicone oil and start using it. You can pay up front or pay in a rears.
FM still has a problem with helping Uncle Xi by feeding his coffers and delaying the weaning process of decoupling from being CC (Communist China) dependent. Now if we could substitute these mainland products with Taiwanese ones, FM would be on board with that while at the same time helping Taiwan remain free and independent. Speaking of that, a lotta countries should take a page from Little Big Latvia on the subject of pushing back against Xi’s bully-pulpit.
FM,
You have a problem?! I know they will not do it, but I personally think they should nuke the next Commie meeting instead of filming and broadcasting it.
The good news is all of Uncle Xi’s cohorts are leaving the Commie Regime as fast as they can. Some of them have figured out that communism does not work. Now if we could just teach that to the DNC.
Back to our regularly scheduled airgun channel.
RidgeRunner,
What this, YOU young whipper snapper… business?
Me soon to be seventy six year old whipper snapper ;^)
I finished my YETI mug of Jacobs Coffee: https://www.walmart.com/ip/Jacobs-Auslese-Klassisch-Ground-Coffee-500g/8513059329?wmlspartner=wlpa&selectedSellerId=101400130
I’m going to try some of the Black Rifle Co. roasts for my next multi day kayak trip.
Even when they were new, and among the few Big Bore airguns, the DAQ Outlaws were reasonably priced by Dennis and built to last for many generations. They were SO well priced that they tripled in open market value when you took delivery. I remember how furious some folk got at the call-in and lottery to get on the list for one.
A bunch of folks got into the airgun building Business as an unintended consequence; some went on to build some quality airguns and some just built TRASH or worse still delivered nothing for all that money they collected up front.
The tide has turned and it is time to load up and get on the water paddling so i Put-In at home before dark.
shootski
shootski,
I am still kicking myself for not snatching up two brand new DAQs when I had the chance. I did not do such because Mrs. RR just would not have understood. Hind sight is 20/20.
Enjoy the water.
RidgeRunner,
Safely off the water at Fort Belvoir Marina on the Dogue Creek. Safe place to park the car and always locked up when outside of normal hours…i paid MWR to get a gate key since i never know for certain how wind, current, waves, and tide will change my ATA (Actual Time of Arrival) compared to my Float Plan estimate.
I have been working on a Digital Night Vision scope system selection for Hog Pesting/Hunting. I’m pretty much settled on the (AGM Global Vision, Neith LRF DS32-4MP, Digital Night Vision, 2.5-20X Magnification, 2560X1440 Resolution, 25 Hz Refresh Rate, 32MM Lens, Matte Finish, Black) it has a range finder and day-night capability. I have been blown away by this consumer level of night vision capability compared to the stuff i used just two decades ago that cost Uncle Sam big bucks. I can only imagine what the best of the best night gear does.
I have been seeing more and more of the feral hog sounders right along the shoreline on my kayak trips on the river. I think it would be a blast to use the .58 DAQ pistol and/or the ShortRifle to cull them; it eliminates some of the risk with these really big ones. I could probably even take a 100 cu ft/4,500psi CF cylinder and my adjustable external regulator in the front or rear hatch and tether for a ridiculous number of full power shots and still have room for my water, change of cloths, tent, camp chair, sleeping bag, mat, stove, coffee, MREs and a toothbrush/toothpaste. ;^)
shootski
shootski,
No they never leaked. I forgot I had one.
BB
B.B.,
ONLY ONE (1)…????
Okay which one (1) did you sell?
Your .458 Outlaw or the .308 1:10 Outlaw?
I declare first dibs (Legalese: Right of first refusal.) on the one you don’t remember.
shootski
shootski.
I sold the .308 many years ago.
BB
B.B.,
Dang!
shootski
B.B.,
You know you NEED to shoot your .458 LA Outlaw again soonest!
I know it will bring on that big grin and i believe you need it!
shootski
Every old lab I’ve been in has a green tube of that Dow Corning silicone grease, also called “high vacuum” grease. It is very thick, like Chapstick, much thicker than Hill pump grease, which is more like a jelly. It is slick when spread thinly but still so viscous that I wouldn’t use it on parts that need to move quickly past each other, like a piston and chamber. We use it on static or slow moving seals like glass-to-glass stopcocks, tubing fittings and vacuum chamber rubber (butyl) seals. Yeah, decades, many decades, and just a thin coating is all that is needed.
Mike
Thank you very much. Now comes the hard part, for one reticent to even slightly disassemble his air rifles: finding the o rings and oiling them! (I guess that’s where schematic drawings come in…) But since I live in a place with four distinct seasons (and no airgun-capable gunsmiths nearby), most will have to wait for Spring to put them to use again since my basement range isn’t big enough for carbines or longer rifles.
Best regards to you!
Rivegauche,
Were you not paying attention? Oil them! It is not necessary to disassemble your airguns to oil them. If you apply silicone oil as BB has prescribed, it will migrate to the O-rings itself. I used to only fill my PCP airguns with a hand pump. That was easy until I started shooting big bore and until the pressures went through the roof.
I used to put a few drops into the end of my hand pump hose, and it would migrate from there into the PCP I was charging. It also provided the benefit of oiling the female foster fitting of my hand pump. This method will work with ANY PCP, no matter what type of fill probe or charging system.
I’ve been paying close attention to Tom’s postings, but typing “were you not paying attention” is less helpful. While placing a drop of oil here and there is obviously simple and beneficial, many of our PCPs come with a set of replacement O rings requiring some disassembly to service. That requires care and precision.
Riveguache,
Forget the extra O-rings. Just oil it. If it leaks after that, then start worrying.
RidgeRunner,
you are rive droite.
shootski
Rivegauche,
With PCP, CO2, and Single/Multi Pump powerplants you can dryfire (Air Blanks) to get the silicon oil from the fill fitting/fill port to spread throughout the air charge system. No need to load a projectile.
shootski
Oil is life! 🙂
Recently I had to change the air input valve at my Stormrider. It just stopped doing it’s job during I pumped the air using my compressor. YES – I bought a cheap compressor (like 350EUR) and I’m delighted. Now I just shoot PCP’s without thinking what will happen to me after, when I have to use a hand pump. Wait… what is a hand pump? Nevertheless, the 1.8kW 300bar compressor has a lot of airflow and it just blow through the air valve – needed to replace it and now it is fine again.
I alwas put a small drop oil on air inlet before I pump the PCP, so far I’m lucky to be sealed all time. Acutally amazing – no air pressure drop since years.
tomek,
Indeed! It can keep everything sliding along smoothly. Very likely if you had done such from the beginning, you may not have needed to replace the inlet valve.
BB,
“Oxygen is extremely flammable” – sorry to nitpick, but you might want to fact check that statement
Bob,
You caught that too, huh?
Not to be inflammatory here, but believe hydrogen takes the prize in the Flammability Department.
Basil,
“Not to be inflammatory?” What are you — a Brit? 😉
BB
Wot?
Quoi ?
FM, you funny.
However, as I had beans for dinner, please keep me away from open flames or HPA today. :o0
RG,
Methane will burn with a beautiful blue flame.
FawltyManuel,
I’ll see your Hydrogen and raise you two puffs of Chlorine Triflouride.
Game Over Man!
shootski
PS: i realized you might enjoy this factoid: https://www.discovery.com/science/Dangerous-Chemical-Chlorine-Trifluoride
and the WW2 connection of this STUFF
Bob,
Yeah I blew it. Oxygen is not flammable; it SUPPORTS oxidation. My bad.
BB
BB,
No worries. I even know some fellow chemical engineers who have made the same mistake 😉
If you own any airgun, good quality silicone oil and grease is your friend. I often use it on ALL of my airguns here at RRHFWA. I have on occasion been known to use light petroleum oil on some leather seals and “Pellgun” oil on CO2 cartridges, but in all of those cases a good quality silicone oil would have worked just fine. It will slick up the innards real good.
Just so you folks know, many years ago I purchased a used AirForce Edge. It did indeed start to leak. After I used my hand pump to insert a little silicone oil into it, the leak stopped. I have been doing such since.
It is my understanding that some folks will say that is not good for a regulator. That, I do not know. I will say this. It did not seem to hurt the regulator in the Edge.
BB
Thank you, thank you! You have brought finality to my often posed question here in recent years concerning using a safe silicon oil in the fill port of REGULATED pcp’s. The potential bugaboo is whether or not regulators are negatively affected by the silicon. Until I hear stop from you I will be confidently putting a couple of drops in the fill probe of all PCP’s at every fill.
Deck
Decksniper,
I know some folks on some forums believe otherwise….
I have had a number (4) of bottle 3,00psi regulators that use Belleville Springs (washers)‡ and have been lubricating them for the past three decades with silicone grease when i take them apart for PM or pressure OUTPUT changes by restacking the Belleville. I use use a few drops of silicone oil in the Foster fill fitting (on the regulator bodies) for most bottle recharges.
I have not had any problems.
shootski
‡https://www.sciencedirect.com/topics/engineering/belleville-spring#:~:text=Belleville springs are compact and,relaxation of a bolt (Fig.
Shootski
If my rememberer is working okay you were one of the first to encourage me to do this. I had just received BB’s golden Ataman P16 and it was my first pcp. I am quite convinced using a correct silicon in fill ports is best way to keep a pcp happy for a long time.
Thanks!
Deck
Decksniper,
Your welcome!
We all share what we know and have found works through experience on this blog of Tom’s.
shootski
The reason o-rings in air guns need lubrication is the ever changing pressure inside the airgun. If pressure was constant the o-rings would not move and never really need lubrication. But since the internal pressure changes the o-rings move and abrade against the metal parts. If the o-rings were lubricated with high vacuum grease (silicone grease) during assembly no oil would be required but from what I have seen with my airguns most o-rings are not lubricated from factory. So a little oil into the fill connection will eventually spread to all the internals and lubricate the o-rings. The other thing is that unlike the military I suspect that the o-rings are not individually packaged and marked with the date of manufacture. All o-rings lose their ductility by degas of the volatiles in the rubber, the loss is greatly reduced if in a sealed package or once installed with the proper lubricant.
The high pressure air systems (1000 to 4500 psig) on a submarine rarely leak but if you depressurize the system to fix a single leak you will always find many more leaks upon re-pressurization of the system. Since typically these systems remain at a constant pressure for years the o-rings will take the shape of the o-ring groove and if depressurized then re-pressurized the o-ring will not return to the original position and hence leak. FYI, there are thousands of o-rings throughout the oil, hydraulic and air systems on the submarine.
Another FYI all o-rings oil, hydraulic, and pneumatic leak it is just a matter of how much and can it be tolerated, ie 0.001 ml/hr is easy to ignore but 1 ml/minute is not easily ignored.
Mike
My biggest concern is a new air gunner or someone just not knowing, tries using the spay type silicon that can be found in any hardware store or big box store. Warning, those aren’t pure silicon. They even say flammable on the can! I’ve been in a bind and used Silicon RC Shock Oil/Diff Oil. They are all silicon. Silicon can be pricey compared to reg oils or Crosman pellgun oil, but if an explosion happens, at best, would cost the gun. At worst, I don’t want to think about it.
Doc
Doc Holiday,
You no doubt know the old saw about leading horses to water…
NEW (and some few old) PCP airgun owners are much more difficult to lead to SILICONE‡ and even harder to get them to give their O-Rings a small drink of its!
‡Silicone: is a class of silicon-based chemical compounds used in paints, adhesives, lubricants, and breast implants, among other applications.
Silicon: Silicon is a chemical element with symbol Si and atomic number 14. Classified as a metalloid, Silicon is a solid at room temperature.
https://grammarist.com/spelling/silicon-silicone/
shootski
B.B. and Readership,
Super Lube® does make Silicone O-Ring grease as well as a bunch of other Silicone based products…even a grease specifically for heat sinks in electronic gear.
Silicone grease has a shelf life of at least five (5) years if stored out of direct sunlight at normal room temperatures. It is not to be used as a lubricant for heavily loaded (not found in airguns) metal on metal as in gear trains. Our bolts aren’t a problem and can actually be greased/lubricated with petroleum based products unless you are going to expose them to extreme cold, dusty, or wet operations in which case a dry lubricant such as:
https://www.super-lube.com/dri-film-lubricant-with-syncolon
or Krytox
would be your best choice.
shootski
What makes airforce airguns less likely to leak? Less seals? Bigger seal surface area? Great article, invaluable information for air gunners and people like me who dream of designing airguns.
tomashi,
I believe fewer o-rings makes AirForce tanks less likely to leak.
BB
tomashi,
“…air gunners and people like me who dream of designing airguns.” A great place to do more dreaming and maybe get some ideas from one of the airgun Greats:
https://quackenbushairguns.com/In_the_shop.htm
Check out the rest of his web page for a true picture of what QUALITY in airguns is really all about.
Enjoy the read,
shootski
I appreciate the information shootski.
Do you know any other resources for air gun design?
tomashi,
Not really.
Much of it depends on which powerplant and for what purpose; personal custom build or manufacturing for retail. Regardless of the aforementioned a good place to start would be a technical education in pneumatics, materials, fabrication, and ergonomics.
shootski
oiling….sometimes it’s too late to oil and you have to replace the o-rings. I looked for vids on how to take the avenge x apart and found none, but it’s not too difficult.
Hey BB Pelletier , will any 100% silicone oil be ok to use?
Beanflip,
Only use silicone oil with a high flashpoint to lubricate PCPs. Ballistol is mineral oil-based so don’t use it for this.
BB
I hate to ask, but for the good of the order, what is a “high flashpoint.” Is there a temperature rating that one should look for?