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Ingress Protection (IP) on "T" joint

Ingress Protection (IP) on "T" joint

Ingress Protection (IP) on "T" joint

I am updating a product made from molded plastic components. Currently the product is IPx2 and it needs to become IPx4.

Please, bear with my explanation, I will not be able to post any images or parts of what I am working with.

The product has a front half, a rear half, and a middle portion sandwiched between the top half of the front and back. The current method of sealing involves applying a "wet seal" onto the edge of the plastic components. Our manufacturing and service departments have requested we switch to a sealing method that is more easily removable (e.g. o-ring, overmolded seal). So this method should be avoided going forward.

I am struggling to figure out how to handle the gap that will exist at the "T" junction. The top of the "T" is a continual edge that has a shape similar to the edge of a hard preformed taco shell. The lower portion of the "T" is a simple "U" shape with the tops of the U touching the bottom portion of the "taco".

How do I close up the pinhole that will likely exist in between the two sealed geometries?

Is there a possible custom 3 dimensional o-ring that can handle this geometry?

RE: Ingress Protection (IP) on "T" joint


I have problems visualising your joint.

Talk to your rubber vendor. One of the things they can do is cut off a piece of rubber tube, and glue the ends together. This gives you a soft o‑ring that will work well is a sloppy joint. Does this help?


RE: Ingress Protection (IP) on "T" joint

Another thing you could look into is form in place gaskets. These cure in place and can be dry when the unit is assembled. because they are applied as a liquid using CNC control they can handle very complicated geometry. The below video is just a reference, I haven't had any experience with that company.


RE: Ingress Protection (IP) on "T" joint

Thank you for the tip, I will contact our supplier and see what they can provide.

That is an interesting method. I will look into it further. Our current seal is applied in a similar manner, but that seal adheres to everything (both mating pieces) and rips apart when the product is serviced. If this can adhere to one surface and stay intact, that will be an improvement.

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