This interesting discussion was started by Roger on the Facebook page, so I've copied and pasted it here for information. I learned a lot from reading this...hope you guys can as well.
Roger Flaherty.
Hi guys, want to lubricate a very small 'o' ring seal on a 1/16 dia push rod and can't remember which lubricant to use. Seem to remember one type can damage 'o' ring. Polite advice please!
David Forrest.
Hi Rog, I think it is silicone grease not vaseline, that you are thinking of!
Steve Juden.
Def silicone grease, do not get them confused else it will be a pain..
Ramesh Wheelerdealer.
Depends on your o rings. If you have silicone o rings, you dont want to get get Silicone grease anywhere near them. Silicone grease is good at keeping nitile and other rubber o rings supple. Vaseline is good for 'packing' to make something water tight, but can degrade some types of rubber. If you want something to lubricate a o ring sealing a rotating shaft then there are better propriatory lubricants.
Roger Flaherty.
Many thanks to all. My latest boat has a tube which is 36mm ID and the two end caps are a tight push fit and I would like to lubricate the 'o'rings to make putting them in and taking out easier. The 'o'rings are black and are designed to fit around a domestic plug. The smaller rings which fit around the push rods are also black. My problem is that with the tube all assenbled I'm getting a small amount of water inside. When I imurse the tube there are no signs of any air bubbles at all and yet I have this ingress. I'm thinking that this may be the air in the tube contracting when placed in cold tap water, pulling vacuum, and drawing the water in as it's volume decreases. If this is the case then it's probably coming in via the push rods and a 'little something' may deter this. Any thoughts?
Richard J Huggett.
How do you tell the various O rings apart, Ramesh? Is there an easy way to differentiate between the different sorts?
Richard J Huggett.
Roger, is there a way you can connect a tube to the cylinder and blow a puff of air inside it whilst it's underwater, then look for the tell tale bubbles of escaping air? Much like mending a puncture in your bike's inner tube where we were kids...
Ramesh Wheelerdealer.
Rich, there is probably some technical way to tell them apart, but Silicone orings tend to be clear or red. Nitrile tends to be black. Silicone is much softer and has less resistance to tearing. Silicone has much better resistance to high and low temperatures, resistance to Chlorine and hence tend to be used in Suba gear and masks, waterproof camera housings, medical and food industries.
Nigel Edmonds.
Silicone seals are normally red and have the texture of chewing gum they are very delicate,I use them in my piston tanks they are much more forgiving on ripply tube and work well on standard acrilic tube, but get the tolerances wrong and you will rip chunks out of them,they must not be lubricated with silicone grease as it attacks them,as anyone who has run silicone oil through silicone tube will tell you.
Nigel Edmonds.
Normal black seals are degraded by pretty much everything including sunlight and water,the trick is to change them on a regular bassis,I have always used halfords general purpose grease on them on both boats and machine tools and have never seen any ill affects from it.
Richard J Huggett.
Thanks for the explanations guys, guess mine are nitrile O rings, so at least I know what to lubricate them with now.
(original postings have been tidied up and Facebook's additions removed)
Richard(ADMIN)
Roger Flaherty.
Hi guys, want to lubricate a very small 'o' ring seal on a 1/16 dia push rod and can't remember which lubricant to use. Seem to remember one type can damage 'o' ring. Polite advice please!
David Forrest.
Hi Rog, I think it is silicone grease not vaseline, that you are thinking of!
Steve Juden.
Def silicone grease, do not get them confused else it will be a pain..
Ramesh Wheelerdealer.
Depends on your o rings. If you have silicone o rings, you dont want to get get Silicone grease anywhere near them. Silicone grease is good at keeping nitile and other rubber o rings supple. Vaseline is good for 'packing' to make something water tight, but can degrade some types of rubber. If you want something to lubricate a o ring sealing a rotating shaft then there are better propriatory lubricants.
Roger Flaherty.
Many thanks to all. My latest boat has a tube which is 36mm ID and the two end caps are a tight push fit and I would like to lubricate the 'o'rings to make putting them in and taking out easier. The 'o'rings are black and are designed to fit around a domestic plug. The smaller rings which fit around the push rods are also black. My problem is that with the tube all assenbled I'm getting a small amount of water inside. When I imurse the tube there are no signs of any air bubbles at all and yet I have this ingress. I'm thinking that this may be the air in the tube contracting when placed in cold tap water, pulling vacuum, and drawing the water in as it's volume decreases. If this is the case then it's probably coming in via the push rods and a 'little something' may deter this. Any thoughts?
Richard J Huggett.
How do you tell the various O rings apart, Ramesh? Is there an easy way to differentiate between the different sorts?
Richard J Huggett.
Roger, is there a way you can connect a tube to the cylinder and blow a puff of air inside it whilst it's underwater, then look for the tell tale bubbles of escaping air? Much like mending a puncture in your bike's inner tube where we were kids...
Ramesh Wheelerdealer.
Rich, there is probably some technical way to tell them apart, but Silicone orings tend to be clear or red. Nitrile tends to be black. Silicone is much softer and has less resistance to tearing. Silicone has much better resistance to high and low temperatures, resistance to Chlorine and hence tend to be used in Suba gear and masks, waterproof camera housings, medical and food industries.
Nigel Edmonds.
Silicone seals are normally red and have the texture of chewing gum they are very delicate,I use them in my piston tanks they are much more forgiving on ripply tube and work well on standard acrilic tube, but get the tolerances wrong and you will rip chunks out of them,they must not be lubricated with silicone grease as it attacks them,as anyone who has run silicone oil through silicone tube will tell you.
Nigel Edmonds.
Normal black seals are degraded by pretty much everything including sunlight and water,the trick is to change them on a regular bassis,I have always used halfords general purpose grease on them on both boats and machine tools and have never seen any ill affects from it.
Richard J Huggett.
Thanks for the explanations guys, guess mine are nitrile O rings, so at least I know what to lubricate them with now.
(original postings have been tidied up and Facebook's additions removed)
Richard(ADMIN)
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