[laka]

We've used nitro before to shrink sleeves to insert into bores. Problem is we don't have the proper flask to store it, so nobody will sell it to us. We usually borrow from another shop, but they closed. Dry-ice is easy to get ahold of, just wondering if anyone has used it for shrinking and could give me any tips?

I read that adding dry-ice to rubbing alcohol will make a very cold liquid which I can submerge the sleeve in.

I have two sleeves, one is about 2.5" OD, the other about 3.5" OD. Both with about 0.150" wall thickness. Was planning on making 0.002" larger than bore size and freezing. We usually do about 0.006" bigger with nitro.

Any comments appreciated.

[Geof]

Dry ice alcohol is nowhere near as cold as liquid nitrogen. I think it is in the ball park of minus 80 degrees C while liquid nitrogen is minus 196, your difference in fit should compensate for the difference in temperature.

Dry ice alcohol certainly is safer to use; you don't have any fear of freezing your fingers solid and breaking them off.

[lowpull]

It is sitting in the back of my head, I dont remember from where is that you use acetone and dry ice.

[amplexus]

The dry ice alcohol mix will work and depending on the sleave material it is easy to figure out how much it will shrink or just drop one in and mike it. Better still check your local dairy farm for liquid N2. Not as cool as crimping with a quarter shrinker but slick nonetheless
Amplexus Ender

[amplexus]

Almost forgot a glass thermos is nearly as good as a dewar flask for short term storage.
Amplexus

[RICHARD ZASTROW]

Or a stainless steel thermos?

Dick Z

[amplexus]

As long as it is double wall glass with vaccuum, I would avoid styrofoam insulation or wear really good gloves.
Amplexus Ender

[mkslice]

We have used dry ice & acetone. Good for -108 deg F. Liquid nitrogen is better due to the -321 deg F. We have been able to get small dewers of nitrogen from the welding gas supply house in town (their dewer).

[Geof]

Almost forgot a glass thermos is nearly as good as a dewar flask for short term storage.
Amplexus

A glass thermos is a Dewar flask.

Dewar was the Scottish guy that invented the vacuum flask, Thermos was the name given to it by a German company that commercialised the idea.

If anyone wants to get really large volumes of liquid nitrogen I have some dewars made out of copper with a capacity of about 100 litres.

[keebler303]

If you use a coffee thermos for LN2, make sure you leave the cap loose. As the LN2 pulls heat from the air, it boils and increases the pressure in the vessel. Big Stainless dewars have pressure relief valves set at 22psi, little guys have loose cork caps so the pressure can't build up. Screw the cap down tight and you will be in for a surprise. Here is what we use for LN2.

Matt

[quadbob]

We used dry ice for the sleeves and heated up aluminum cylinder castings when I used to work in model Shop for an outboard Mfg. We got about .007 differential between the two