Bearings & Bushings for Underwater Use w/o Housing | Get Details

[malek340]

I'm currently finding a bearing or bushings that can work underwater without a housing with minimal rust. Do anyone have an idea if it can? If there is, pls give me the details of the bearings or bushings?

 

[Mech_Engineer]

It's hard (or impossible) to give you really useful feedback without some sort or information about the application... but I'll wager a guess at stainless steel bearings? I think oxidation will be less of a problem than lubrication under water though.

 

[malek340]

But won't stainless steel still rust that fast? I resesrched and found that it still rust. My application would be using a bearing or bushing that is attached to a shaft for a motor tp run underwater. The equipments will be placed underwater for quite a long time

 

[Mech_Engineer]

It depends on what stainless you're using, and what the "water" is (I'm assuming you mean salt water?). Stainless 316 is a marine-grade stainless steel and pretty tough stuff. It could give you a pretty high resistance to corrosion, but no stainless is 100% corrosion proof.

Of course if you're talking salt water (or any electrolyte), you also need to worry about Galvanic Corrosion. Are you aware of the difference?

http://en.wikipedia.org/wiki/Galvanic_corrosion

 

[malek340]

Is there a known bearing that is made up from stainless steel 316? Btw bearings needs oil to be lubricated..So is it impossible to place it under sea water? Is there a way to use bearings underwater

 

[Mech_Engineer]

Bearings are of course used underwater in all kinds of applications, as far as I know the "best practice" way to do it is to seal them from the water using o-rings and gaskets. This also allows retention of lubrication.

 

[malek340]

I'm seriously becoming desperate. I need a bushing or bearing that is able to work without sealing it. Is there really nothing that can work underwater just like that?

 

[malek340]

Shaft and bushing underwater

Recently i found a polyacetal bushing from Misumi and planning to use it for my underwater application(please do tell me if it can't be use when submerged in sea water). I'm planning to a attach it to a stainless steel shaft which will be rotated by a motor. Do u think it will work? Enlighten me pls.

 

[Bobbywhy]

malek340, To discover if your polyacetal bushing will survive the stainless steel motor shaft and the saltwater environment it seems to me the logical place to find out is Misumi Customer Service. If you are in the USA you might call them and ask:
MISUMI USA
1717 Penny Lane, Suite 200
Schaumburg, IL60173
USA
Phone 1: (847) 843-9105
Phone 2: (800) 681-7475

Cheers,
Bobbywy

 

[Bobbywhy]

There are lots of mechanisms already rotating shafts underwater through a saltwater-impervious bushing. Ships, boats, outboard motors, pumps, directional sonar arrays are just a few examples. What do they use?

 

[malek340]

I just recently found out about polyacetal bushing but am not too sure yet. Any thoughts?

 

[Mech_Engineer]

There's just no way to give you any more specific information without knowing SOMETHING about your application...

 

[Jobrag]

Have you thought about Lignum Vitae?

 

[etudiant]

Ceramic bearings are becoming pretty routine and should be quite salt water resistant.
However, I believe they are currently offered primarily in small sizes.