Thought I'd pop a little thread into chat about O-rings.
It seems that most of you buy from Airsoft shops and pay well over the odds for them. So I thought I'd put a link or two up and mention what they are and how you go about getting them at the correct price.
O-rings are a basic seal. Used worldwide for hundreds of applications. They fall into a standardised measuring system for 99% of applications Airsoft included.
O-rings are not magical items made by Airsoft companies, to their own standards. Rather Airsoft has made components that fit into the standards that O-ring manufacturers produce. As such you can go to any Bearing and Seal supplier and they can measure the rings and sell you the correct ones off the shelf.
For the purposes of Airsoft pistons and cylinders we are only concerned with 1 material, and that is Nitrile sometimes called Buna-N. It's one of the more common materials, and meets the demands of airsoft perfectly, having good oil resistance, reasonable heat resistance, and enough elastication to be pushed and compressed to seal the rather sloppy manufacturing standards in airsoft.
Compressed gas rings are also often nitrile, but it is good to take the ring to the Bearing supplier and have them look at it as there are other materials like EPDM and Viton, and you might have an oddball. Some chemicals can significantly affect O-ring material, EPDM for example is not suitable to propane applications and most companies have a list you can check compatibility with.
Buying rings is as simple as measuring them, be as accurate as possible, and consider you may have imperial (inch) specification rings (I have not had an encounter with imperial rings at all in airsoft but it's not to say it doesn't happen). Sloppy airsoft standard will mean you will need to pick to the nearest 1mm in most cases. Depending on the application you may need to round up or down depending on the seal you need to make.
O-rings are measured in 2 dimensions. Thickness of the band, and Inner diameter. And a third specification is given to the shore hardness of the ring (exactly the same as buckings). Standard is 70 shore hardness for nitrile, but harder and softer rings are available.
A typical piston head ring is therefore 2.5mm x 19mm x 70 shore hardness. These rings are 50 for £5. Or 10p each in most cases.
A typical Cylinder head ring is 1mm x 19mm x 70 shore hardness. Again typically 50 for £5.
The formula for measurement is correct for every o-ring on your guns. You can't find the right ones to space an inner barrel, Measure the OD of the inner barrel, and pick a thickness of ring that will bridge the gap to the ID of the outer barrel. Remember you will have to add the thickness twice.
So OD inner barrel 8mm, ID outer 10mm.
would be a 1mm x 8mm x 70 shore hardness (the math is 1+8+1 = 10mm).
This site does all of the above, And it gives more measurement options than the standard 2. Use the chemical compatibility chart. And save some money buying in bulk, It's generally a very similar price for 2, 5, 10 and 50 rings! And the postage is free regardless of the order size.
https://simplybearings.co.uk/shop/Seals-O-Ring-Seals/c19_4501/index.html
It seems that most of you buy from Airsoft shops and pay well over the odds for them. So I thought I'd put a link or two up and mention what they are and how you go about getting them at the correct price.
O-rings are a basic seal. Used worldwide for hundreds of applications. They fall into a standardised measuring system for 99% of applications Airsoft included.
O-rings are not magical items made by Airsoft companies, to their own standards. Rather Airsoft has made components that fit into the standards that O-ring manufacturers produce. As such you can go to any Bearing and Seal supplier and they can measure the rings and sell you the correct ones off the shelf.
For the purposes of Airsoft pistons and cylinders we are only concerned with 1 material, and that is Nitrile sometimes called Buna-N. It's one of the more common materials, and meets the demands of airsoft perfectly, having good oil resistance, reasonable heat resistance, and enough elastication to be pushed and compressed to seal the rather sloppy manufacturing standards in airsoft.
Compressed gas rings are also often nitrile, but it is good to take the ring to the Bearing supplier and have them look at it as there are other materials like EPDM and Viton, and you might have an oddball. Some chemicals can significantly affect O-ring material, EPDM for example is not suitable to propane applications and most companies have a list you can check compatibility with.
Buying rings is as simple as measuring them, be as accurate as possible, and consider you may have imperial (inch) specification rings (I have not had an encounter with imperial rings at all in airsoft but it's not to say it doesn't happen). Sloppy airsoft standard will mean you will need to pick to the nearest 1mm in most cases. Depending on the application you may need to round up or down depending on the seal you need to make.
O-rings are measured in 2 dimensions. Thickness of the band, and Inner diameter. And a third specification is given to the shore hardness of the ring (exactly the same as buckings). Standard is 70 shore hardness for nitrile, but harder and softer rings are available.
A typical piston head ring is therefore 2.5mm x 19mm x 70 shore hardness. These rings are 50 for £5. Or 10p each in most cases.
A typical Cylinder head ring is 1mm x 19mm x 70 shore hardness. Again typically 50 for £5.
The formula for measurement is correct for every o-ring on your guns. You can't find the right ones to space an inner barrel, Measure the OD of the inner barrel, and pick a thickness of ring that will bridge the gap to the ID of the outer barrel. Remember you will have to add the thickness twice.
So OD inner barrel 8mm, ID outer 10mm.
would be a 1mm x 8mm x 70 shore hardness (the math is 1+8+1 = 10mm).
This site does all of the above, And it gives more measurement options than the standard 2. Use the chemical compatibility chart. And save some money buying in bulk, It's generally a very similar price for 2, 5, 10 and 50 rings! And the postage is free regardless of the order size.
https://simplybearings.co.uk/shop/Seals-O-Ring-Seals/c19_4501/index.html
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