PDA

View Full Version : Learned More on Paper about Tungsten Disulphide



ckelloug
05-29-2012, 08:38 PM
Since I brought up the Tungsten Disulphide a while back, I figured I'd share what I learned.

After doing some more research about Tungsten Disulphide, it appears that it has to either be blasted onto or lapped into the surface to work. The stuff came from NASA and the aerospace companies say you get near permanent lubrication with a .5 micron layer thickness. Apparently, it forms a pretty good bond with the surface once it gets on there.

While I was researching, I found some of the aerospace companies in LA that use the stuff. Dicronite won't even sell WS2 lubricant, they will either apply it for you or license the process.

--Cameron

lazlo
05-29-2012, 08:47 PM
Interesting -- that's not entirely consistent with the web page cited on the other thread. At least, the "blasting" on the lowerfriction.com site consists of 120 psi, which is spraying it out
of a sandblaster nozzle:

http://www.lowerfriction.com/product-page.php?categoryID=1

Two established ways the WS2 powder can be used are:

1) Mixing the WS2 powder with wet lubricants (such as oil, grease & other synthetic lubricants):
The powder can be mixed 1wt% to 15wt% (as required) with grease or oil. This will enhance lubricity of the mixture and also improves High Temperature and Extreme Pressure properties of mixture. During the use, WS2 in the mixture will get coated on mating/moving parts, which in turn reduces friction and improves lubricity and load bearing ability for much longer cycles.

2) Coating the WS2 powder on a substrate requiring (dry) lubricity:
The powder can be coated by spraying (at 120 psi) the substrate with dry (& cool) pneumatic air. It does not require any binders and spraying can be done at normal room temperature. Coated film will be 0.5 micron thick. In an alternative application method, the powder can also be mixed with Isopropyl alcohol and this paste could be buffed to the substrate. The coating applications are already established in many areas such as Automotive parts, Racing Car Engine and other parts, Aerospace parts, Bearings (Linear, Ball, Roller etc), Shafts, Marine parts, Cutting Tools, Blades, Slitters, Knives, Mold release, Precision Gears, Valve components, Pistons, Chains, Machinery components and many other areas.

lynnl
05-30-2012, 11:01 AM
.......
Dicronite won't even sell WS2 lubricant, they will either apply it for you or license the process.

--Cameron

Cameron, I'm a little confused by that statement. That link in lazlo's posting presents an option to buy it. ...1 lb bag for $54.

Is the "Dicronite" you mention a different supplier?

ckelloug
05-30-2012, 12:23 PM
Lynn, Thanks for pointing out the confusion.

I was trying to clarify the apparent troubles using WS2 cited by the gentleman who was trying to make a moglice replacement and found WS2 to be more sticky than slippery.

I am in LA right now and I was nominally trying to lubricate the column in a CH Products flight yoke so that the PC based flight simulator we have at Harvey Mudd College will work better. I was curious to try WS2 since it is dry and said to be permanent. I looked for LA suppliers of WS2 and found Dicronite:

Dicronite http://www.dicronite.com/ is a company that will treat parts with WS2 but won't sell the WS2. They talk a lot about wanting licensees for their process.

My point in bringing this up was that it appears that successfully using WS2 may be a bit harder than dusting the surface you want to be slippery with the stuff. I brought up something very slippery which is also apparently hard to use. . .

T.Hoffman
05-30-2012, 01:41 PM
I have heard of some burnishing their automatic pistol slides with ws2 as well.

I haven't tried that, but I'm about to add ws2 to my recenly acquired Ranger on the next oil change.

lazlo
05-30-2012, 01:56 PM
I have heard of some burnishing their automatic pistol slides with ws2 as well.

It's also very popular to coat bullets (for reloading) with WS2

http://www.6mmbr.com/bulletcoating.html

lazlo
05-30-2012, 01:58 PM
My point in bringing this up was that it appears that successfully using WS2 may be a bit harder than dusting the surface you want to be slippery with the stuff.

I'm curious to try this method described on the lowerfriction.com web site:


"the powder can also be mixed with Isopropyl alcohol and this paste could be buffed to the substrate."

darryl
05-30-2012, 05:51 PM
Lazlo, that method tweaked my interest as well. If it works as well as blasted-on coating, it would be a good all-round method for the home shop.

Rex
05-30-2012, 06:06 PM
Worth a try. Where do you buy it?

H380
05-30-2012, 07:49 PM
Better link.

http://www.accurateshooter.com/technical-articles/guide-to-bullet-coating/

dian
05-31-2012, 05:54 AM
so, i mixed it with alcohol, rubbed it onto a polished shaft. after it dried, it came off, it scratched the shaft. i rubbed it onto a rough shaft. it embedded a little. so i have a slippery rough shaft?

race a the granite plate:

i put three ground buttons on a clean, polished granite surface. one used way oil, one a mix of tds with same way oil, third was dry.

http://i973.photobucket.com/albums/ae218/romandian/x082.jpg

i then raised one end of the plate and watched. after having done it several times, here is the result:

tds button takes off a little earlier, but the way oil button is much faster. big surprise: third button takes off first and is off the plate by the time the other ones start moving.

hmm, putting the stuff into my engine, i dont know. the sucessful application of tds probably is not trivial.

Euph0ny
05-31-2012, 10:09 AM
Dian,

is that one of those Rohm blank-firing pistols to the left in your photo? My brother-in-law once gave me his non-functional one for cleaning - I couldn't believe how much soot and gunk could accumulate inside... but it worked again once I scraped out the rubbish.

T.Hoffman
05-31-2012, 10:29 AM
tds button takes off a little earlier, but the way oil button is much faster. big surprise: third button takes off first and is off the plate by the time the other ones start moving.

hmm, putting the stuff into my engine, i dont know. the sucessful application of tds probably is not trivial.

...don't think this is the most telling way of doing this.
Not that I have a great way of doing home-shop experiments with ws2, but this doesn't seem like the best expeirment.

I would think looking at a friction wear pattern over a length of time with treated vs untreaded might be a better approach?

lazlo
05-31-2012, 11:54 AM
...don't think this is the most telling way of doing this.

Agreed - he's measuring stiction. Like you say, Tungsten DiSulphide is closely related to Molybdenum Disulphide -- it's an extreme pressure additive.

dian
05-31-2012, 01:30 PM
eupho, thats exactly what it is, a röhm rg3 6 mm. i didnt even notice it was there.

otherwise im mainly interested in reducing the stick slip (for shop purposes). if this doenst do it, i will no more mess around with it.

as i stated before, the stuff doesn feel especially slippery. also, it scratched the (unhardened) shaft.

Low-alloy
05-31-2012, 11:12 PM
so, i mixed it with alcohol, rubbed it onto a polished shaft. after it dried, it came off, it scratched the shaft.


The fact that it is scratching the surface of metal is pretty troubling--and may have led to its poor performance on the slide test? Could the Tungsten DiSulphide have been contaminated somehow? Anybody else that has used tungsten disulphide noticed any roughening of surfaces during/after application?

I was hoping that Tungsten DiSulphide was going to be the oil additive or dry lube, now I am not so sure.:(

Cheers!

Low-Alloy

lazlo
05-31-2012, 11:51 PM
I was hoping that Tungsten DiSulphide was going to be the oil additive or dry lube, now I am not so sure.:(

When someone first posted about WS2 a couple of weeks ago, I did some idle reading, and apparently the issue with Tungsten disulfide being an oil additive is that it's so dense that it's nearly impossible to keep it in suspension.

As far as scratching the parent material, I think the general usage model is like lapping abrasive: the harder Tungsten disulfide crystals are supposed to embed in the softer parent material, and act like ball bearings.

T.Hoffman
06-01-2012, 12:40 AM
.......and apparently the issue with Tungsten disulfide being an oil additive is that it's so dense that it's nearly impossible to keep it in suspension.

With larger particles, yes- but that's 'permently suspended'.
If they do tend to settle, usually the agitation of the fluid within the motor or gearbox generally spins them up back into circulation.

Guy on my motorcycle forum who's an engineering geek did some experiments with particle size and settling over time.
He used an industrial Vitamix blender to suspend very small particle ws2 powder.
He had different blending times and observed the setting amount over time with clear bottles.

ckelloug
06-01-2012, 02:01 PM
From what I've read, WS2 properly applied in a thin layer forms a van der waals bond with the surface and is there forever. You don't want any more WS2 on your surface than is necessary to do this which means rub or blast on and remove the excess. It also likely means that you have to disperse it to a great extent as clumps of the stuff will probably have more tendency to bind to each other than the surface.

A suspension of something this dense would undoubtedly settle so in order to get a stable colloid of it, you need to have a very small particle size.

Based on the van der wall force adhesion I'm fairly sure the more is better adage doesn't apply. My predicted usage method would be to mix at very high shear with alcohol and then rub it on. Other van der wall force related work I've done suggests that there is probably an optimal amount of it in the solution you want to use. The question for me now is really how high a shear do you have to mix it under before the tiny particles go around coating things nicely.