PTM gets asked this one a lot: if SBR gaskets cost less than natural rubber gaskets, why not buy SBR every time? Sometimes you should. Other times it’s a false economy, and the difference comes down to a few properties you can check in a minute.
Strip away the price, and these two rubbers are close cousins. Both give good to excellent resistance to water and good resistance to acids and alkalis. Both are poor with oils and fuels. Neither enjoys the outdoors, since natural rubber has poor ozone resistance and SBR only fair. If the joint will see oil or petrol, or sit outside in strong sun, neither is the right answer, and our rubber material guide will point you towards nitrile or EPDM instead.
Natural rubber springs back better. Compress it, release it, and it returns to shape more willingly, which matters on a gasket that gets squeezed again and again, such as an inspection cover opened every week, or one that doubles as a buffer. It also copes with 10°C more heat, though 80°C hardly counts as extreme. Natural rubber gaskets made to BS1154 follow a recognised British Standard too, so the grade stays the same whoever supplies it.
SBR wins on price. For a static joint under steady bolt load, sealing water or a mild chemical in ordinary conditions, it does the job without fuss.
So which one should you buy? A rough rule covers most jobs. Choose SBR gaskets for static joints in water or mild chemicals, where nobody will notice the difference. Move up to natural rubber gaskets when the gasket gets compressed and released regularly or needs extra bounce-back. Either way, check what’s touching it first, since oil ruins both.
Both are cut to order, from a single piece up to full production runs, across our rubber gasket range and wider gasket range. Tell PTM what the gasket will seal through the contact page, and we’ll give you a straight answer. Or just call 01625 573971 or email sales@epdm.co.uk.
