Lubricious coating for CDA 360 brass for Viton seal to reciprocate...
Lubricious coating for CDA 360 brass for Viton seal to reciprocate...
(OP)
Hi All
Does anyone have a feel for what coating can be used to reduce the friction for a Viton Plug (75 Shore A) reciprocating in a brass bore?
We are considering NiCoTef and Hi T Lube and Nedox PF-F but are there better?
TIA
Q~
Does anyone have a feel for what coating can be used to reduce the friction for a Viton Plug (75 Shore A) reciprocating in a brass bore?
We are considering NiCoTef and Hi T Lube and Nedox PF-F but are there better?
TIA
Q~
RE: Lubricious coating for CDA 360 brass for Viton seal to reciprocate...
What is the fit in the cylinder ?
I'm guessing process contamination from those lubes is no porblem.
RE: Lubricious coating for CDA 360 brass for Viton seal to reciprocate...
yes, it's a solid Viton plug, 1/2" dia x 1/2" long and is pressed into the bore with ~ .003" diametral squeeze.
no process contamination from any of the ones listed. we have used Krytox in the past with excellent results but does not stay forever - looking for a hard coating to cover the CDA 360 brass and become more permanent...
RE: Lubricious coating for CDA 360 brass for Viton seal to reciprocate...
Perhaps you are using too much interference?
When the plus slides is it being pushed, so that it is trying to expand more?
Wouldn't a plug with raised seals at both ends be more effective?
The problem with a coating is that the brass is so soft that over time it will not support it.
A relief in the center of the plug would also allow for a small reservoir of Krytox.
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P.E. Metallurgy, consulting work welcomed
RE: Lubricious coating for CDA 360 brass for Viton seal to reciprocate...
It's not possible to provide constructive suggestions without knowing the complete set of requirements and constraints.
RE: Lubricious coating for CDA 360 brass for Viton seal to reciprocate...
No not burnished but reamed to a 32uIN finish.
The people @ General Magnaplate state the coating Nedox PF-F is 65Rc. Does that help?
RE: Lubricious coating for CDA 360 brass for Viton seal to reciprocate...
I would look at methods to longitudinally polish the ID.
There should be no circumferential marks, unless you hone and leave a nice diagonal crosshatch.
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P.E. Metallurgy, consulting work welcomed
RE: Lubricious coating for CDA 360 brass for Viton seal to reciprocate...
RE: Lubricious coating for CDA 360 brass for Viton seal to reciprocate...
Mint - you are correct - the application requires the Viton plug to be pushed into the bore lifting a ~ 5lb load via a piston on the other side. It has been performing fine for years but we noticed recently a "stickage" issue where if sat idle for months there's a breakaway friction issue with the Viton plug where the 5 lb load isn't enough to overcome and return to retracted position
Ed / TBE - next step for us would be 303SS - is that hard enough?
RE: Lubricious coating for CDA 360 brass for Viton seal to reciprocate...
We used to make some sleeves in Nitronic 50 and break them in with a very hard rubber plug (ours rotated). We would run them roughly equal to the expected service life (but sped up of course). Then in service with the softer seal plug they worked very well without coatings.
303 will always have a slightly rough surface, which could help you (less surface contact and lube retention), or it could hurt you (tearing of the rubber). It isn't very good for coating because of the large inclusions in the structure.
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P.E. Metallurgy, consulting work welcomed
RE: Lubricious coating for CDA 360 brass for Viton seal to reciprocate...
Next stock material we use is 316L SS or 2507 Duplex SS. Any better?
Btw - 303SS sure seems to look like a material best used for non-critical service components like handles etc LOL…