Hi all,

I realize this is way off topic, but I'm hoping that the collective wisdom
here might stray into the required area of expertise...

I need to create a thin sheet of ice (.0125"-ish) on a plywood ramp
approximately 12" wide and 60" long, and I need to do it quickly; no longer
than 10 minutes. I can't build anything substantial into the ramp (IOW, no
refrigeration coils under the ramp), but anything else might be feasible.
Dry ice and water? I've heard some fire extinguishers could be used to
freeze water? Any suggestions?

Peter

On Fri, 31 Dec 2004 02:42:36 GMT, "Peter Grey"
wrote:

Hi all,

I realize this is way off topic, but I'm hoping that the collective wisdom
here might stray into the required area of expertise...

I need to create a thin sheet of ice (.0125"-ish) on a plywood ramp
approximately 12" wide and 60" long, and I need to do it quickly; no longer
than 10 minutes. I can't build anything substantial into the ramp (IOW, no
refrigeration coils under the ramp), but anything else might be feasible.
Dry ice and water? I've heard some fire extinguishers could be used to
freeze water? Any suggestions?

Do a Google search on supercooled water. Under the right conditions
water can be cooled to below freezing temperature withoutt freezing.
I don't know if you could get transferred from the container to the
plywood without it freezing en route, but it might be worth a try.

Don Foreman wrote:
On Fri, 31 Dec 2004 02:42:36 GMT, "Peter Grey"
wrote:


Hi all,

I realize this is way off topic, but I'm hoping that the collective wisdom
here might stray into the required area of expertise...

I need to create a thin sheet of ice (.0125"-ish) on a plywood ramp
approximately 12" wide and 60" long, and I need to do it quickly; no longer
than 10 minutes. I can't build anything substantial into the ramp (IOW, no
refrigeration coils under the ramp), but anything else might be feasible.
Dry ice and water? I've heard some fire extinguishers could be used to
freeze water? Any suggestions?


Do a Google search on supercooled water. Under the right conditions
water can be cooled to below freezing temperature withoutt freezing.
I don't know if you could get transferred from the container to the
plywood without it freezing en route, but it might be worth a try.


I didn't get the original post, but another google search would be for
"Hilsch vortex tube" which can be made from plumbing fittings, and
outputs supercooled AIR. Maybe shooting into a temporary insulated box
over the ramp, which contains a water mist spray?

Ken Grunke


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On Sat, 1 Jan 2005 00:30:36 -0800, "Roger Shoaf"
wrote:


Also you want to have ice cold water inside the sprayer.

Even better... one sprayer with hot water, and one with cold, so that
he can make a definitive report to the readers of the "freezing pipes"
thread. :-)

Wayne

"Peter Grey" wrote in message
nk.net...


It's for a contest that involves rolling/sliding model vehicles down the
ramp and I'm looking for "the unfair advantage".


Does the ramp have to be plywood?

I have doubts that this will work on the typical roughness of plywood.
I think it will stick rather than slide freely. How about making the
bottom of the object flat, drilling a hole in the center, and supplying
compessed air form a tiny internal tank? An air bearing will likely
work a LOT better, and the friction will be as close to zero as you're
going to get.

Jon

Peter Grey wrote:
I'm thinking liquid nitrogen...?

Mixing liquid nitrogen and water is VERY dangerous, as the nitrogen will
boil explosively!

Cooling an object with liq N2 and then spraying water on it is at least
safe, but will result in some pretty rough ice. I suspect you want some
smooth ice.

Jon

Gunner wrote:


I rather liked the air bottle "hovercraft" idea. Ive seen folks use
3/8" plate and an airhose to move very large machinery like magic.


That's a neat idea. Do they just tap the air supply into the middle of
the plate, or what?

Ken Grunke


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On Sun, 02 Jan 2005 18:52:23 -0600, Ken Grunke
wrote:

Gunner wrote:


I rather liked the air bottle "hovercraft" idea. Ive seen folks use
3/8" plate and an airhose to move very large machinery like magic.


That's a neat idea. Do they just tap the air supply into the middle of
the plate, or what?

Ken Grunke

Yup. just put an air fitting on it and hook an airline to it with a
valve to control air flow. While it makes moving things easy..it
doesnt do anything for inertia...seen a couple spectacular booboos
when they got it moving too fast and then shut off the air a bit too
quick.

Gunner



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