Sciencemadness Discussion Board

acetone intollerant substance

allyncondon - 5-12-2008 at 05:00

Hi i am wondering does anyone know what can be used to polish steel after it has been sanded to a smooth finish but will not be removed when wiped with acetone. The surfaces are polished to a fine finish to run smooth over ice but am looking for something to give them even more speed.any help will be appreciated

chemrox - 5-12-2008 at 07:58

steel that will not be removed by acetone? that can't be the question. what are you asking?

hissingnoise - 5-12-2008 at 08:26

Chemrox, I think he wants to apply some kind of wax to the steel to increase its slipperiness on ice.
I don't know of any polish insoluble in acetone, but there could be one, possibly.
The finer the finish, though, the more slippy the steel.
After that, you're talking small rockets on skates. . .

bfesser - 5-12-2008 at 11:38

Teflon.

Nicodem - 6-12-2008 at 06:45

You could try hydrophobizing with CH3(CH2)17SiCl3 or CH3(CH2)17Si(OEt)3. As far as I know, both are relatively quite cheap and are said to actually work on steel. This way you will not just get the most ice slippery steel possible, but as a bonus you also also protect it from corrosion. There are other hydrophobizing reagents you could use that might work better at forming a hydrophobic monolayer on steel.

allyncondon - 9-12-2008 at 04:22

would the steel need treating with the solution before or after they had been sanded and then if they were wiped with acetone and lemon after would the solution still be effective

hissingnoise - 9-12-2008 at 07:12

(sigh) Allyn, applying a coating and sanding it off is *not* a good idea.
As for acetone and lemon---one is a potent organic solvent and the other is acidic; will the thing work without wiping your steel with either of them?

kclo4 - 9-12-2008 at 15:28

Perhaps if you tell us what you are doing, we could help more?
I like the hydrophobic idea. What about other options to decrease its friction? Perhaps getting it really hot would cause the Ice to vaporize, so it would essentially ride down on the steam/air? Or, try using dry ice (solid CO2) as it has different properties.

hissingnoise - 10-12-2008 at 11:26

Since Allyn may want more speed in ice-skating, a tentative look at the physics might be in order.
Ice in contact with steel liquefies at the interface when pressure is applied and it is the lubricant effect of this liquid layer which makes ice appear slippery.
If the surface of the ice is some degrees below zero increased pressure is needed for this liquefaction.
Ice, then, at O*C will be slippier than ice at a lower temperature.
The size of area of steel in contact with the ice also has a bearing; a smaller area effectively increases pressure (from the skater's weight) on the steel, allowing for easier liquefaction.
Polishing the skate's steel surface along its length will allow the skate to move easily on ice and using extra-fine abrasives to finish will help in this regard.
Skates with a mirror-finish should, I imagine, have increased speed over skates with a duller finish.
It's probably a question of elbow-grease---and time! Lots of it. . .

vulture - 10-12-2008 at 13:42

Teflon. IIRC, the friction coefficient between Teflon and ice is the lowest known to man. Teflon is also resistant to acetone.

kclo4 - 10-12-2008 at 15:51

Quote:
Originally posted by hissingnoise
Since Allyn may want more speed in ice-skating, a tentative look at the physics might be in order.
Ice in contact with steel liquefies at the interface when pressure is applied and it is the lubricant effect of this liquid layer which makes ice appear slippery.
If the surface of the ice is some degrees below zero increased pressure is needed for this liquefaction.
Ice, then, at O*C will be slippier than ice at a lower temperature.
The size of area of steel in contact with the ice also has a bearing; a smaller area effectively increases pressure (from the skater's weight) on the steel, allowing for easier liquefaction.
Polishing the skate's steel surface along its length will allow the skate to move easily on ice and using extra-fine abrasives to finish will help in this regard.
Skates with a mirror-finish should, I imagine, have increased speed over skates with a duller finish.
It's probably a question of elbow-grease---and time! Lots of it. . .


Are you sure it melts? I've heard that it had to do with some sort of funky bonding thing that makes the top layer of molecules able to bend and flex.
Also this talks about how as the sub-zero ice temperatures increased, so did the friction.
http://www.geo.hunter.cuny.edu/~hsalmun/ice_phy2day.pdf

12AX7 - 10-12-2008 at 16:46

Common misconception: the pressure is in fact too low (by orders of magnitude) to cause melting by pressure. It's just ice's low coefficient of friction at work!

Tim

hissingnoise - 11-12-2008 at 04:34

Quote:
Originally posted by kclo4

Are you sure it melts?


I've always believed it melts, but I haven't given it much scrutiny (until now).
It's what I was told and I accepted it without a lot of thought.
Experience appeared to verify it. . .

hissingnoise - 11-12-2008 at 07:34

Quote:
Originally posted by 12AX7

The pressure is in fact too low (by orders of magnitude) to cause melting by pressure.


Tim, that's not correct; try the weighted wire loop on the ice-cube trick.
It demonstrates the principle leaving the ice-cube intact and the wire on the floor.

12AX7 - 11-12-2008 at 09:05

Ah, but what weight? The pressure is much higher (maybe an order of magnitude or two), depending on what size of wire used.

In this diagram for instance:
http://www.lsbu.ac.uk/water/phase.html
it can be seen that pressures over 10MPa (100 atm / 1500 PSI) cause a noticable drop in melting point of ice Ih. A 100kg (= 1kN) skater on two 20 x 0.25 cm skates (0.2 x 0.0025 * 2 = 0.001 m^2) exerts a pressure of 1MPa. On edges, where the area is a tenth of this or less, pressure may become a factor, but skates slide just as well flat so this isn't a useful explanation.

Their statement:
http://www.lsbu.ac.uk/water/explan2.html#Pmelt

Tim

hissingnoise - 11-12-2008 at 09:27

I think the passage of unweighted wire through ice would be exceedingly slow, but even unweighted wire would eventually make its way through an ice-cube.
I've noticed a certain shoe-stickiness on ice in very cold weather; my weight, presumably, isn't enough then to cause melting of the ice, whereas newly-formed ice seems very slippery.
Skates, though, have very small areas in contact with the ice.
The attachments do look interesting but I haven't time to read them in full.

allyncondon - 13-12-2008 at 05:40

hi just to clear things up it is actually bobsleigh and steel runners the problem is they cannot be heated as the runners have to be within 2 degrees of the test runners and before each race we sand the runners to get them prepared but before we compete they have to be run over with a low grade paper(5 wipes) and then wiped with both acetone and lemon to clear of anything apparently put on them

hissingnoise - 13-12-2008 at 05:53

Arrgghhh! You're just looking for an unfair advantage over your competitors!

Detritus!

(just joking)

allyncondon - 13-12-2008 at 10:01

well i am actually trying to find out what unfair advantage other competitors are gaining over us

hissingnoise - 13-12-2008 at 11:34

OK, not a Welsh ice-skater, or someone on an innocentive challenge, but your difficulty isn't easily soluble.
There is a marine polish which contains teflon powder but the binder (carrier) may not stand up to acetone---worth googling possibly?

[Edited on 13-12-2008 by hissingnoise]

12AX7 - 13-12-2008 at 12:49

Construct the runners out of polished carbide (or carbide coat them).

Tim

hissingnoise - 13-12-2008 at 13:57

Tim, Allyn may not know you're referring to tungsten carbide.
If he uses calcium carbide, for instance, he might go through the sound barrier on that thing, gassing or incinerating everyone following behind.

12AX7 - 14-12-2008 at 06:27

Or titanium carbide, or silicon carbide, or hafnium carbide (the highest melting solid), or any other carbide used structurally for strength and abrasion resistance, the purpose of which should've been obvious.

Tim

hissingnoise - 14-12-2008 at 06:42

Yes those would be more long-lasting but CaC2 would be more, er, interesting, IMO.
(snigger)