One of the most common applications for some of our cork gasket materials is making automotive gaskets. Therefore, a question we get asked a lot is: Is cork ok for use with fuel?
Really, it depends. It’s not the cork part that is the issue here. Pure cork granules are resistant to petrol and diesel by themselves. The point of potential failure lies in the rubber that is used to bond these cork parts together to form a sheet.
Anatomy of a Cork Gasket Sheet.
Cork Gasket Sheets are hybrid products made up of cork granules and a binder. This binding agent is usually made from rubber but, on rare occasions, can also be plastic.
Changing the binder changes the properties of the cork sheet. Increasing it will increase elasticity, decreasing it will increase the roughness of the material. As an extreme example, think of the texture of a cork notice board which has very little binder.
Part of the reason cork gasket materials weigh so much more than other types of cork sheet (such as those used in construction) is the presence and proportion of the rubber binder. It’s heavier than the cork and increases the density of the sheet.
Which Cork Gasket Sheets are Good with Fuel?
Generally speaking, if you’re making cork gaskets for sealing petroleum or diesel, you want to use a cork material with a Nitrile Rubber Binder (sometimes referred to by it’s short-hand code: NBR).
Within the rubber family, Nitrile has some of the best fuel resistance (rivalled only by Viton / FKM rubber which is almost never used for binding cork sheets). Unlike many other types of rubber, fuel doesn’t break Nitrile down meaning your gasket will retain its’ strength and compressibility over a long service life.
If a Nitrile Bonded Cork Sheet isn’t an option, a secondary choice would be a Neoprene bonded cork. It’s not as good as Nitrile, but it can withstand fuels to a limited degree. Personally, I wouldn’t use it but it may be good enough in a pinch.
Where Can I Get Nitrile Bonded Cork Gasket Sheets?
We are pleased to offer a range of Industrial Grade Nitrile Bonded Cork in a full selection of thicknesses and a variety of sheet sizes. You can browse our online range here.
We can also produce custom cut gaskets from this quality cork gasket material. For obvious reasons, these aren’t listed in our online shop but please do contact us if you’d like a quote.