what lube to use for o rings on benjamin handpump

[MDStroup]

http://www.ebay.com/itm/Airgun-Chamber-Lube-Pure-100-Silicone-Oil-2X-Crosman-Silicone-Chamber-Oil-/291551026977?hash=item43e1cb9f21

Do you think that this lube would work for lube for the pump as well as the air gun?

[nervoustrigger]

Says it's pure silicone oil, just does not give the viscosity.  So it may be just fine but why pay more for 0.5oz than a 2oz bottle on Amazon?

http://www.amazon.com/gp/aw/d/B0006MZSRW

[MDStroup]

Says it's pure silicone oil, just does not give the viscosity.  So it may be just fine but why pay more for 0.5oz than a 2oz bottle on Amazon?

http://www.amazon.com/gp/aw/d/B0006MZSRW

Thanks. I actually  have  that exact  bottle in my eBay shopping  cart. But it is 45wt. I just didn't know which onewould be better. So do you think the 45wt would be fine then? Because  tomorrow  when my Hill mk3 pump arrives I am immediately  tearing  it down an lubing it and checking all o-rings.

[nervoustrigger]

Yes, I think 45W would be fine.  In this application I don't think you'd see any appreciable difference between 30W and 45W.  Some folks have used up 60W and seemed to be satisfied with how it works.

[MichaelM]

think my bottle of silicon oil is 50wt lol pretty sure if you rin the ball park you will be fine...

[DavidinTennessee]

Guys, you generally want to use silicone oil for dynamic (moving) O-rings in a high pressure pump.  30W silicone oil is a good viscosity.  It is sold as R/C shock oil.  That is, oil for the shocks of radio controlled cars.  Search "silicone shock oil" at hobby shops or Amazon.
 
Silicone grease, on the other hand, is better suited as an assembly lube for static (non-moving) O-rings.  It is usually too viscous to be preferred for sliding O-rings.  I don't know whether it will have any adverse effects on wear and longevity, but it made pumping noticeably more difficult when I tried it.
 
If you want to use something more exotic, look at the Krytox GPL 10x series.

I went to fill my rifle the other day and found the same issue with my pump. I used Danco silicone plumbers grease. I have the 25W Lucas silicone shock oil. I will try that. Really, I haven't had issues with my pump at all. I do take it apart once a year and dump the water out of the base. Even with a desiccant canister, the pump base fills with H2O.

[SFZX]

I was told by Sun Optics (the manufacturer of the Pump) that you should use Non Detergent 30W motor oil.

Actually that is not what you were told by Sun Optics and the the designer of the Benjamin pump. He said to use nothing but MOBIL ONE FULL SYNTHETIC ONLY AND VERY LIGHT COATING OF IT. 5-30 IS FINE. THIS HAS AN EXTREMELY HIGH FLASH POINT. They never said a thing about 30W non detergent oil.

[chiro972b]

I was told by Sun Optics (the manufacturer of the Pump) that you should use Non Detergent 30W motor oil.

Actually that is not what you were told by Sun Optics and the the designer of the Benjamin pump. He said to use nothing but MOBIL ONE FULL SYNTHETIC ONLY AND VERY LIGHT COATING OF IT. 5-30 IS FINE. THIS HAS AN EXTREMELY HIGH FLASH POINT. They never said a thing about 30W non detergent oil.

I don't know if that's all that high for a flash point. I just looked at the product data sheet and it says 230C. I'm not so sure you don't see momentary temps like that when compressing the air, but maybe I'm wrong. I used to race RC cars and have lots of silicone shock oil left over. That's what I used and it has worked fine.

[Deane]

I was told by Sun Optics (the manufacturer of the Pump) that you should use Non Detergent 30W motor oil.

Actually that is not what you were told by Sun Optics and the the designer of the Benjamin pump. He said to use nothing but MOBIL ONE FULL SYNTHETIC ONLY AND VERY LIGHT COATING OF IT. 5-30 IS FINE. THIS HAS AN EXTREMELY HIGH FLASH POINT. They never said a thing about 30W non detergent oil.

Personally, as a highly-trained aircraft mechanic who holds a Federal Aviation Administration (FAA) Airman Certificate for Mechanic with ratings of Airframe and Powerplant, and has worked in aviation for over 50 years, I would NEVER use any product with a “flash rating” on a high-pressure system. There is a reason the FAA has regulations restricting what substances you can use on high-pressure and oxygen systems. IT CAN GO BANG! Ignition (fire) needs three things, heat, fuel, and oxygen. In this case, the fuel (combustible substance such as petroleum), the heat (from compression), and oxygen (in the air that we are compressing). If a substance has a flash point, by definition, it is combustible! Be safe! Never use anything with a flash point no matter how high it is.

[FuzzyGrub]

I was told by Sun Optics (the manufacturer of the Pump) that you should use Non Detergent 30W motor oil.

Actually that is not what you were told by Sun Optics and the the designer of the Benjamin pump. He said to use nothing but MOBIL ONE FULL SYNTHETIC ONLY AND VERY LIGHT COATING OF IT. 5-30 IS FINE. THIS HAS AN EXTREMELY HIGH FLASH POINT. They never said a thing about 30W non detergent oil.

FWIW: Back when I started in PCP, like many, started out with a Benji pump.  At that time Sun Optics did recommend Non-Detergent 30W Motor Oil.   

Regardless, do what Jason recommendeded.  Silicone oil on dynamic, silicone grease on static O-rings.