WD40 and Rubber

[pestobanana]

So to everyone it's "common knowledge" not to use WD-40 on airsoft guns, because they say it will eat away at o rings. Is there any evidence of this?

I've used WD-40 on guns when I was a newbie about 7 or 8 years ago, and those guns still work fine. The cans themselves actually say that they are good for use on O-rings, in fact synthetic rubber is petroleum based. Some mechanics say they use WD-40 on O-rings with no problems. As a part time instrument repair technician, I was taught to use WD-40 on O-rings to help prevent air leakage in metal insert vents, and to prevent water buildup which affects pitch.

[zone 69]

Originally Posted by pestobanana

So to everyone it's "common knowledge" not to use WD-40 on airsoft guns, because they say it will eat away at o rings. Is there any evidence of this?

I've used WD-40 on guns when I was a newbie about 7 or 8 years ago, and those guns still work fine. The cans themselves actually say that they are good for use on O-rings, in fact synthetic rubber is petroleum based. Some mechanics say they use WD-40 on O-rings with no problems.

I don't think it's the same for silicone. But hay what do I know.

[pestobanana]

Originally Posted by zone 69

I don't think it's the same for silicone. But hay what do I know.

I've used it on silicone over the top of an octave vent thread on an instrument (my own) and there have been no negative affects.
As far as I know it's bad for natural old school rubber, but O-rings nowadays are all synthetic rubber, so moisture doesn't affect anything. It's also not good for certain polycarbonate and polystyrene plastics.

[ShelledPants]

WD40 is not a lubricant to be used with airsoft guns, it is a water displacement liquid (thus the WD in WD40), it is too low a viscosity to replace the higher viscosity of proper silicone oil . You would have to constantly relube the gun as the WD40 will blow off quicker than silicone oil. /thread.

[pestobanana]

Originally Posted by ShelledPants

WD40 is not a lubricant to be used with airsoft guns, it is a water displacement liquid (thus the WD in WD40), it is too low a viscosity to replace the higher viscosity of proper silicone oil . You would have to constantly relube the gun as the WD40 will blow off quicker than silicone oil. /thread.

Actually I've experimented with that, and I find it consistent with their technical description. It itself is a lubricant, which seems fairly light when you spray it, because it is diluted with a light solvent. That's what makes WD-40 highly viscous and good for seeping into threads. Once the solvent evaporates, the lubricant remains, and feels about the same as the mineral oil I use for rod bearings and maintaining blades on gouging machines. The stuff left over doesn't evaporate.

I still use silicone oil and lithium grease in my gearboxes, I'm just trying to see if there are any verifiable negative effects of using WD40.

[Dimitri]

Originally Posted by pestobanana

feels about the same as the mineral oil I use for rod bearings and maintaining blades on gouging machines. The stuff left over doesn't evaporate.

• 51% of WD40 is Turpentine/White Spirit/naphtha (or what ever you want to call it).
• 20% is made up of alkanes. The long carbon chains (longer then Gasolines C8H18), which cannot absorb water, and are used to repel the water.
• 15% of WD40 is Mineral oil.
• 5% is CO2 to propel the above.
• And the rest of WD40 is inert ingredients that do nothing.

The Turpentine and Alkanes group however, just like gasoline doesn't play well with rubber. So when you spray WD40 on your nice rubber seals, your actually spraying mostly things that are going to damage the rubber.

Dimitri

[ThunderCactus]

WD-40 is not a valid lubricant. Period.
Every SMART millwright in industry will aggressively ring your neck if they catch you with a can of WD-40

It's primarily used to displace water off of surfaces, and it also contains a good amount of mild solvent (naptha/turpentine/whatever), making it useful for cleaning. But it's by no means a permanent lubricant.
Case and point, we all used WD-40 to lube our bike chains when we were young. Ever notice how they got RUSTY over winter? Yeah they don't do that when you use the proper gear chain or wax lubricant.
And it does absolutely disintegrate rubber seals. Note there are many different kinds of rubber used for seals, some are more prone to breaking down than others, and most rubbers are synthetic these days.

The industry standard is to never use WD-40 ever on anything. Use solvents if you need a solvent, and use lubricant if you need a lubricant.
Would you rather have 15% lubricant and 85% something else on your seals, or 100% lubricant?

[Dimitri]

Originally Posted by ThunderCactus

WD-40 is not a valid lubricant. Period.

While true, and for people like both you and I, we know this as we learned this in industry. Others have not had that opportunity to learn.

The reason that WD40 is not good for rubber is the Turpentine and Alkanes that make up the vast majority of a can's contents. Both that would aggressively eat away at rubber compounds.

There is a gray line forming now that there are synthetic rubbers designed to withstand solvents and other petroleum products (such as your cars tires). There are still however many applications where even some synthetic rubbers are sensitive to petroleum products. The original poster seems to have lucked out with his rubber seals on his original AEG's.

But penetrating oil, such as WD40 (or some of the better commercial alternatives personally I like Crown's offering but that is purely subjective) have their uses in a shop.

An outright ban of them is silly, especially since most machinists and millwrights I know refuse to use WD-40 and then go and use one of those "Breakaway" agents to undo rusted bolts which is just penetrating oil with a fancy name on the can.

Dimitri