window seal epdm hardness 2

[Ponuliukas]

Hello,
I'm working with metal parts, but this time i have to create a rubber seal. Unfortunately rubber types is not my strong side. So i would like an advice about it. I have to design a rubber seal for a small window. The design of rubber is shown in the picture. i was thinking about epdm, but i dont know what hardness should i choose.
Outside diameter: 128mm
Inside diameter: 98mm
Thickness:1mm
There will be 4 m4 bolds in the holes (pressing the windows frame+seal to the metalic surface.
The hardness should be quite soft to fill all the surface roughness, but not too soft, since under the pressure it should not increase it's outside diameter above 130mm(the size of window outside frame).

so what epdm hardness could fit in this situation?

 

[johnnymat]

EPDM is the correct choice for a window seal and to get the balance between obtaining the correct complinace to mating faces and creating the seal without excessive bulging you should choose a hardness of 70IRHD or 70Shore A ( at this hardness there is little diffrence in the twio scales)

JohnnyMat

 

[RubberDog]

I would even go a little lower, about 60 Shore A.
This ways you don't force too much the counter parts.
But the above also should work. Don't see too much difficult here.