jnelson33
Mechanical
- Mar 7, 2018
- 53
Hello All,
I am trying to figure out how much to crimp an Epichlorohydrin (ECO) hose down onto a fitting. I'm not looking for numbers, this is all just conversational technical discussion. Our ECO hose has a Viton liner bonded to it as well. With respect to cross-section thicknesses, the Viton is about 1/3 as thick as the total wall is, so it's not really the primary elastomer here. Therefore, most of what I'm talking about will concern the ECO rubber.
My research on ECO rubber has told me about its horrible compression set. Unfortunately, our supplier can't give me an MDS, so I can;t say any discrete properties about their compound. Since ECO rubber does have this characteristic, my thinking is as follows; due to ECO rubber's bad compression set, it would make sense to fully compress the rubber down to a "solid" to ensure that sealing on the fitting is never an issue, correct? If the rubber has been fully compressed, but not plastically deformed, losing the seal should not be an issue for the life of the hose, and my design successfully accounts for that elastomer's negative characteristics.
Unfortunately most of what I turn-up in a search for compression set is all about O-rings, so that's why I am here. For an O-ring they say to do the opposite, less compression is better, which makes sense based on O-ring sealing principles. It's really only sealing on a line, and you want that line to exist while keeping its shape in a dynamic setting, or last for years in a static setup, so over-squeezing the wrong elastomer can be horrible for O-rings, aside from other failures of course.
I am trying to figure out how much to crimp an Epichlorohydrin (ECO) hose down onto a fitting. I'm not looking for numbers, this is all just conversational technical discussion. Our ECO hose has a Viton liner bonded to it as well. With respect to cross-section thicknesses, the Viton is about 1/3 as thick as the total wall is, so it's not really the primary elastomer here. Therefore, most of what I'm talking about will concern the ECO rubber.
My research on ECO rubber has told me about its horrible compression set. Unfortunately, our supplier can't give me an MDS, so I can;t say any discrete properties about their compound. Since ECO rubber does have this characteristic, my thinking is as follows; due to ECO rubber's bad compression set, it would make sense to fully compress the rubber down to a "solid" to ensure that sealing on the fitting is never an issue, correct? If the rubber has been fully compressed, but not plastically deformed, losing the seal should not be an issue for the life of the hose, and my design successfully accounts for that elastomer's negative characteristics.
Unfortunately most of what I turn-up in a search for compression set is all about O-rings, so that's why I am here. For an O-ring they say to do the opposite, less compression is better, which makes sense based on O-ring sealing principles. It's really only sealing on a line, and you want that line to exist while keeping its shape in a dynamic setting, or last for years in a static setup, so over-squeezing the wrong elastomer can be horrible for O-rings, aside from other failures of course.