Need Information About Rubber and Plastic

I think the answer is as far away as your toilet tank. Just find out what they make the rubber flapper out of.....................they last for a lot of years before needing replacing.

That is what I am trying to find out. They do deteriorate over time. I would like something even better.

The PVC/CPVC piping in my house has been here since 1983...............it's still holding up fine. You may want to also look in the silicone family.

Does it just sit there, or does it have to do something?

It has to encapsulate a spring to keep the spring from rusting.

I feel 20 questions coming.

Coil spring; leaf spring; torsion bar.................

Tell us what you are trying to do. Not what you want.

To be more specific "a 3/4" long push spring 1/4" in diameter. It must be protected from moisture. I own an ultrasonic welder and can get tooling to seal it. Thanks

What is this spring made of? Why not make the spring out of something that will not deteriorate during prolonged immerions, such as stainless steel, instead of covering it with something?

I agree with ↑. Tell us what you are trying to achieve, not what you want to find, preferably in a single posting, not 20.

Byron, you said "To be more specific "a 3/4" long push spring 1/4" in diameter. It must be protected from moisture."

So, you need an accordion type action from a rubber sleeve, with this spring inside?

The clarity of and volume of your information should both be increased.

I don't know about anybody else, but I learned something. This was presented in a kind, gentle and nurturing manner, without the... aw, never mind!

Regarding the original question, "Need Information About Rubber and Plastic", this comment seems to be useful, and I vote accordingly.

_{This should take you to 500... again. Let's see if it sticks this time.}

Thanks for the kind, gentle compliment.

Yep, that's deserving enough for my vote.

That is a very complex and pretty complete answer. I am wondering if real rubber like comes from a rubber tree would work. I am not much of a chemist so I am just lost and depending on smart people like you.

yes, all plastics absorb water. All materials reflect light. All movement is a ratio of time to distance. These kinds of absolutes are not very useful to a practical engineer. If a small amount of absorption, (which you say is the best anyone could hope to do) is acceptable to build a tool with a twenty year life expectancy, it is indeed adequate. It's about measurement and analysis, not obsessive absolutes. I will never let anyone tell me plastics can't absorb water.

Just covering the spring with plastic or rubber that holds up well to submersion opens other problems. It will change the force values of the spring. The bond of this material has to take the continuous shear forces of compression. If it doesn't water seeps in and it rusts.

You say for the product's life time. Even a spring has a life time. It can't be flexed for ever. Even these plastics and rubbers that do hold up in water deteriorate sooner or later. So what's the life of this product to be?

Stainless Steel hold up well in water.

Thanks everyone. Tomorrow I will take down the question. I found the answer and appreciate all of your help.

Can you tell us what the solution is?

"Lee springs" They are made for food processing equipment and for marine applications. I just needed to get out of the box and try something different. Thanks again to all who participated.

Simple and cheap plastics like LDPE, LLDPE, HDPE are all capable of remaining under water without getting affected. They do not absorb water and retain their properties for several years. If you need sealing properties and flexibility, then you have to use either thermoplastic elastomers or Ether based polyurethane material. If you want to go for rubber, Neoprene would be ideal choice. Even natural rubber, compounded with suitable anti oxidants/ozonants or Nitrile PVC can also be used. Depends on the cost you can afford to pay.

I must have a giant bulls-eye on my back.