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?
Has anyone else experienced something similar and had a successful resolution?
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RE: Sticky O-ring
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
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.
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