Re: Chain Waxing, hot, Why it Works?

41 wrote:
Peter Cole wrote:

41 wrote:


Old fashioned paste floor wax, like good automobile wax, relies on
carnuba (carnauba) wax, the hardest and highest melting point natural
wax. It is both chemically and physically very different from paraffin:


I can find no information for the
specific formulation of any paste floor w ax. Do you have some, or are
you just speculating?


I knew in advance that this was the traditional ingredient and the
reason for that, and googled "carnuba" to find a specific value for the
hardness- and to also see if it was still commonly used as such.
Answer: yes, and furthermore it is used for other things far more
commonly than I would have expected (it used to be expensive). For
example, it seems we are eating a lot of it.

I have used paste floor wax and carnauba-containing car wax and ski wax, etc. etc. They are all lubricants because they share the property of melting at the pressure point and forming a film of high strength separating the sliding components. This "It's a dessert topping! No, it's a floor wax!" discussion, while entertaining, is beside the point.



Wax sticks well to plastic, and because it's hydrophobic will displace
the water film between the board and skin.


Try reigning in the speculation a bit. If what you say were true, then
to dry the soles of my feet, I need only step on a paraffined board. Of
course that does not happen.

Of course it does. Try rubbing a wax of your choice under water, it
won't be slippery. If the water film remained it would be.


Today I wet my thumb, and pressed it against paraffin, either slowly or
quickly raising the pressure to as high as I could manage. I then
removed my thumb from the paraffin. In both cases it remained as wet as
before.

I don't think you're trying hard enough.

I then tried rubbing that wax both dry, and under water. In both cases
it was not slippery, and there was not much difference between the two,
but I would say that the wet wax was slipperier.

As in the case above, you won't get any where near 100% contact between skin and wax, there will be pockets of water and water in the fingerprints.


Wax has high film strength, that's what makes it prevent floor scuffs.


Carnuba is indeed very strong (strong enough for a bicycle chain? I
doubt it but don't know). However, paraffin is not. Paraffin is also
very brittle.


I thought you were referring to hardness, since we were talking about
the solid state. Film strength usually refers to the liquid state.

Yes, which is where waxes do their lubrication.

I'm sure there are many papers describing the use of wax lubricants in
industrial applications, here's one I found quickly:
<http://www.hitachi-pm.co.jp/english/seihin/tec-report/2002/pdf/tec2002_e_05.pdf>

Sliding Property of F e-Cu-C Sintered Materials under High
Contact Stress and at Low Sliding Velocity

"If wax is used as lubricant for impregnation instead of oil, the
durability of the bearing can be increased, because wax has a stronger
film intensity and about
2.7 times as large a coefficient of thermal expansion as that of
lubricating oil."


I give you an "A" for googling but only a "Gentleman's C" for reading.

The key paragraph is the following:
[snip]
One reason for the good performance of the wax is
its high film strength.

This is the only part of relevance to my argument. I was rebutting the claim that waxes have poor film strength. I'd rather not participate in broadening the argument.

You think waxed floss wouldn't make a difference on dry teeth? I beg to
differ. You've obviously not done much hand sewing where bee's wax is
used to lubricate the thread. No water there.


We are straying very far from bicycle chains (porous reservoir
bearings, cloth fabric, dental floss). In fact the cloth should have a
water content similar to the relative humidity of the atmosphere.
Whatever, obviously paraffin does not make for the highest friction
pair, I am merely saying it is not slippery (like oil or ice is
slippery).

It is precisely slippery like ice is slippery, in that under pressure it melts, forming a strong film that separates sliding parts. Melted wax does have higher viscosity than water, so the film will have higher friction than water.


But this is of no matter: as I said somewhere else, what
(should be) considered a lubricant depends on the context. Of course if
you have a very high-friction pair, then putting a medium friction pair
coating on will help. But the specifics matter: in sewing, the pressure
between fabric and thread is zilch.

It is certainly not. Do the math if you doubt it.

In dental floss, you have one
entry, a few rubs, and one exit, and I don't know that the pressure is
so high.

Again, do the math.

In bicycle chains, you have very high pressures and very many
passes to squeeze any wax, solid or putatively liquid, out from the
interface, and no mechanism to recirculate it back- unless you want
porous sintered pins and links. No thanks.

The pin and inner plate shoulder interface bears a load only on a fraction (less than half) of its surface. The remaining surfaces are never compressed, so the wax wouldn't be squeezed out. The loaded surfaces do rotate (unloaded) over the never-loaded surfaces, so it's at least possible for reservoirs of wax to persist and replenishment to occur.


As an aside, carnuba is or at least was also used as a wax on dental
floss, although paraffin may be used too, perhaps in combination. As
another aside, MP's example of waxing surfboards interested me and I
found this:

http://en.wikipedia.org/wiki/Paraffin
Uses

Candlemaking
Coatings for waxed paper or cloth.
Coating for many kinds of hard cheese, like Edam cheese.
Preparing specimens for histology.
Solid propellant for hybrid rockets
Sealing jars, cans, and bottles
In dermatology, as an emollient (moisturiser)
Surfing, for grip on surfboards as a component of surfwax.
[...]

I'm not sure what you're trying to show with this list. Wax is not used as a lubricant on surf boards, but rather as a traction surface.

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