Engineering

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A place to geek out about engineering, fabrication, and design. All disciplines are welcome. Ask questions, share knowledge, show off projects you're proud of, and share interesting things you find.

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Need some advice on creating a waterproof container that allows for a sliding stainless steel rod (sh.itjust.works)

submitted 4 months ago by [email protected] to c/[email protected]

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Hello lemgineers!

I'm working on designing a claw that can be operated underwater. The plan is to use a linear actuator in a waterproof housing. The main issue is allowing the shaft to slide through without causing a leak. What's the best way to go about this?

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[–] [email protected] 1 points 1 week ago (1 children)

Sorry I'm just now seeing this, and late to the party is just fine 😍 I'm looking at redesigning it this year anyways!

I'm not sure if this is similar to what you meant by an accordion covering, but what we did was design a mold that we 3D printed and poured silicone into to create a seal/cover that will stretch as the piston of the linear actuator slides in and out.

[–] [email protected] 1 points 1 week ago

I meant with the pleats, similar to what you see on an actual accordion, or in a bendy straw. It's how they did the joints on the Apollo space suits, for a vaguely similar application. The shape is sometimes called "bellows", but that's pretty confusing when it also refers to an air blowing technology that may or may not involve a diaphragm of any kind.

If you got enough range of movement with just a straight elastomer cylinder, that works, but if the pressure is pretty modest a variety of stretchy ducts made for HVAC or other home purposes are sold. I have some for draining rainwater, but they seem to break in stiff wind, so YMMV. You could also mold your own again.