PrometheusX
Members
- Jun 9, 2019
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Do any of you grease inside the cylinder?
Does it make for better compression and less friction?
Does it make for better compression and less friction?
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Grease inside cylinder?
- Thread starter PrometheusX
- Start date
I use grease normally. A lot use oil.
The advantage to grease is it stays where you put it and you can guarantee a coating will last.
The advantage to oil is it's thinner and takes less force to shear.
Once shearing has happened there is no difference in friction between a good silicone grease and good silicone oil.
The only issue you may have with greases is the NGL rating. The scale runs from 000 to 5, 000 been near oil thickness, 5 been lard.
I find NGL 1 to 2 (soft to medium) are about right.
Above NGL 3 the o-ring isn't under enough force to shear the grease fully hence it slows the piston down.
O-ring material shouldn't be a problem with silicone grease/oil.
EPDM, Nitrile/Buna-N are both inert to it.
The only thing we really have trouble with in airsoft is propane and butane in GBB guns. EPDM is dissolved by it! Nitrile/Buna-N is recommended.
If in doubt there are loads of charts for O-rings where you can look at what ring is resistant to what chemicals. It helps a lot when you are having trouble with keeping seals working and can't work out why your rings are failing!
For your piston airseal you have to understand how the O-ring is working to understand that it makes no difference in what you use.
The seal is created on 2 faces. The outer wall of the cylinder, and the back of the o-ring seat on the piston head. Grease and oil do not act to fill space and help create a seal, The O-ring and those faces make the seal. For the best seal you need a piston head with a solid smooth back wall on the O-ring seat, and a smooth finish on the cylinder.
Rough spots/Damage on those faces will damage the o-ring. And once damaged the ring will no longer work correctly.
A decent piston head will have no flex in the material of the backwall. If it flexes then it's not going to give a perfect seal. Plastic heads can be good, but not all are equal, APS heads, for example, are very poor on the back wall.
The advantage to grease is it stays where you put it and you can guarantee a coating will last.
The advantage to oil is it's thinner and takes less force to shear.
Once shearing has happened there is no difference in friction between a good silicone grease and good silicone oil.
The only issue you may have with greases is the NGL rating. The scale runs from 000 to 5, 000 been near oil thickness, 5 been lard.
I find NGL 1 to 2 (soft to medium) are about right.
Above NGL 3 the o-ring isn't under enough force to shear the grease fully hence it slows the piston down.
O-ring material shouldn't be a problem with silicone grease/oil.
EPDM, Nitrile/Buna-N are both inert to it.
The only thing we really have trouble with in airsoft is propane and butane in GBB guns. EPDM is dissolved by it! Nitrile/Buna-N is recommended.
If in doubt there are loads of charts for O-rings where you can look at what ring is resistant to what chemicals. It helps a lot when you are having trouble with keeping seals working and can't work out why your rings are failing!
For your piston airseal you have to understand how the O-ring is working to understand that it makes no difference in what you use.
The seal is created on 2 faces. The outer wall of the cylinder, and the back of the o-ring seat on the piston head. Grease and oil do not act to fill space and help create a seal, The O-ring and those faces make the seal. For the best seal you need a piston head with a solid smooth back wall on the O-ring seat, and a smooth finish on the cylinder.
Rough spots/Damage on those faces will damage the o-ring. And once damaged the ring will no longer work correctly.
A decent piston head will have no flex in the material of the backwall. If it flexes then it's not going to give a perfect seal. Plastic heads can be good, but not all are equal, APS heads, for example, are very poor on the back wall.
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PrometheusX
Members
- Jun 9, 2019
- 43
- 1
- Thread starter
- #4
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