Cold, colder, Coldest

[rverdoold]

Sorry no question about cars here, but some related fluids. 

 

For a scientific experiment we have to rapidly freeze our samples. Normally we do this by dipping them in liquid nitrogen at approx -200 C. But this is in the lab, with a liquid nitrogen tap. Now we are going to conduct this experiment outside the lab and we can not take the liquid nitrogen.

 

So we thought of an alternative:

1. Mixing ethylene glycol (pure) 2/3 with 1/3 water, and add dry ice, now we should be able to reach -60 C in liquid state. But ethylene glycol is to toxic to work with!

2. Mixing propylene glycol (pure) 2/3 with 1/3 water, same as number 1 but less toxic. However we can not get our hands on it from car parts shops, only from chemical supplier at 99% purity while 85% would be sufficient so it is quite expensive.

3. ATF, but when does it solidifies (or what is the melting point)?

 

Other oils will be to viscous and to dirty to use, ATF I think is not so oily as motor or gearbox oil.

[Fairtax4me]

Ethylene glycol really isn't bad, just don't eat it. You should be wearing gloves anyway since you'll be handling -60C cold stuff.

 

How much do you plan to use?

[rverdoold]

2 quarts to a gallon, which is almost half of what is in my Impreza.

[1 Lucky Texan]

what about the stuff they use in water systems in RVs ?

 

or; http://www.orisonmarketing.com/IceclearAF.html

 

In the past, i used an environmental test chamber that use liquid CO2. You have to find the cylinders with the siphon tube. maybe a gas company could make up a smaller cylinder for you. Still, there's gonna be handling/usage problems.

 

are alcohols too flammable? -100 C or colder I think.

Edited April 15, 2014 by 1 Lucky Texan

[rverdoold]

Problem is we need it on saturday and i thought propylene glycol would not be that hard. But now we will order it from Sigma chemicals. 

The iceclear is up to (or down) -36 C, and indeed alcohol is to flammable.

[1 Lucky Texan]

Problem is we need it on saturday and i thought propylene glycol would not be that hard. But now we will order it from Sigma chemicals. 

The iceclear is up to (or down) -36 C, and indeed alcohol is to flammable.

it'll probably get slushy but, should still work I guess. Things can sometime be crazy in the field so - try to find time for a 'dry run' in the lab with the new fluid.