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Molded or Vulcanized O-Rings, Which is Best for your Application?

The first thing that hits the mind when you think about sealing your equipment or machinery with O-Rings is molded O-Rings and the amount of lead time required for manufacturing custom molded O-Rings. You have to hire a O-Ring manufacturing company that takes into account your application needs, manufacture a mold and then use it to mold custom O-Rings for you. This process can easily take up 4-6 weeks. However, vulcanized O-Rings are a quick solution where a cord stock is cut to a required length for the diameter and bonded with a bonding agent (glue) to form O-Ring. The vulcanized O-Ring keeps your assembly line running without a long delay. Both of these types of O-Rings are suitable for specific kinds of industrial applications where one may be suitable for a certain application, but it might fail in another. The things to consider while selecting the type of O-Ring that will be suitable for your application includes:

Application Pressure

In applications where O-Rings will be subjected to harsh and pressure intensive use, vulcanized O-Rings will not be able to perform well in such applications. If your machinery or equipment will impose a lot of pressure on the O-Rings, then you must go in for molded O-Rings for your application. Also, if your application requires long term use, molded O-Rings is a better solution. For a general guideline, vulcanized O-Rings can bear up to 1200 PSI, while molded O-Rings can bear up to 1500 PSI.

Turnaround Time

When you are in urgent need of o-rings for static applications, the best solution for you may be vulcanized o-rings. Vulcanized o-rings  are generally produced in lead times as short as 2 business days but same day service is also possible. If you need a large quantity or need o-rings for dynamic service,  then you can choose custom molded o-rings. For molded o-rings, the manufacturer has to first prepare a custom mold as per the required specifications of o-rings and then use this mold to manufacture the o-rings, which is typically a long lead time.

Quantity Required

  • If you require just a few O-Rings, then the best solution for you is to use Vulcanized O-Rings as they are cost-effective and require a low cost to manufacture. The amount of time and effort required to produce molded O-Rings makes it costly to manufacture them if the quantity required is low. Hence, they are not a cost effective or profitable solution for low quantity.
  • On the other hand, for larger quantities, molded O-Rings are a faster solution and more cost-effective. A large number of vulcanized O-Rings can be produced, but it requires more-man hours and is a longer process compared to machine molded O-Rings.
  • Also, if you require a number of O-Rings, but in different sizes, then again vulcanized O-Rings is a better solution as they don't require manufacturing a mold to manufacture them.

Static or Dynamic Environment

If your application is a static one where the O-Rings won't be subjected to moving components, vulcanized O-Rings is the suitable solution as they hold up the sealing application quite well in such environments, whereas for dynamic or moving components one must select molded O-Rings.


Whether you need molded, vulcanized or both types of O-Rings completely depend upon the requirement of your application. If you need any assistance, Contact COR, our experienced team can happily answer your questions and help you find the right solution for your application.

You can also read our blog on vulcanized o-rings to find out more about them.

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