×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Sticky O-ring

Sticky O-ring

Sticky O-ring

(OP)
Excuse my lack of O-ring design experience, but we are currently using an EPDM o-ring on a Polyester (PBT) housing, in which either a Polycarbonate (PC) or PBT lid gets screwed onto. The O-ring is a radial seal and is designed to have between 8-25% compression. I should also add that we are using a Molycote #44 lubricant that is compatible with EPFDM. The problem comes when the lids are screwed down on the housing, they go on very nice, but when left for a day or two they are very difficult (Sticky) to remove the lids.

Has anyone else experienced something similar and had a successful resolution?

RE: Sticky O-ring

Any sign of any of the materials softening/getting tacky? I wouldn't expect it, as all of those are compatible with silicone.

Radial seal to me means the o-ring is trapped between two cylinders. That can be a tricky part to disassemble at any time. We have added a thread in our covers to allow a pull ring to be threaded in to aid disassembly. I've also seen push threads (through threads in the cover) that allow a screw to be threaded in and bear on the mating flange to push the cover out. Even a screwdriver pry slot or two might help.

RE: Sticky O-ring

Hi!

Sorry to be so late!

Standard EPDM O-Rings' compound tend to be more stickier than other standard rubber o-ring material. This can be the reason why it works fine at mounting but after a time (enough to get off the grease on the contact area) it becomes more difficult.

On the other hand, you are using a compression range that is too much under the point of view of sealing. A penumatic O-Ring seal needs about 10% and 20% on hydraulics

My proposal. If your system will be for a large quantity, try to get a EPDM compound that is less stickier, otherwise use a Plastic ring on the contact surface, so less friction will be applied.

http://www.hidromar.es

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close