What is dry ice?
Simply put Dry Ice is frozen Carbon Dioxide at temperatures of -79c. It is made by using liquid carbon dioxide and jetted out via a nozzle at an extremely fast speed, collected and compacted into blocks. You can obtain Dry ice in sheets, blocks or pellets. However your best option is in pellet form (around 3mm size) as you need a medium to suspend the dry ice in The smaller the dry ice pellets are the better; in order for the medium to cover as much surface area as possible.
Here are the Pros and Cons of both types.
Dry Ice blocks (cubes)
The Block Form of Dry Ice
Pros:
- Cubes sublime at a slower rate than pellet form.
Cons:
- Because if the size and its suspension in the medium, lower temperatures can be achieved with pellet rather than block form.
Pellets
Dry Ice in Pellet Form
Pros:
- The medium covers more surface area of the dry ice allowing more efficient cooling
Cons:
- Does not last as long as block form
What is the medium that has been mentioned a few times already?
Dry ice cannot be used by itself; it must be suspended in a liquid form (the medium) in order for the dry ice to have as much surface area covered as possible.
What liquid can I use?
Liquids used are alcohol based and there are many, however overclockers mostly employ the following fluids;
- Ethanol (like vodka) can be used, but this freezes at -25
- Isopropyl thickens at -50 (looks like Syrup at this temperature) but freezes at -89
- Acetone (Nail Polish remover) Freezes at -93
- Propanol freezes at -130
The first three substances are easily obtainable however propanol is not. Acetone is more efficient but stinks to high heaven when you first start. So the best all round option, would be Isopropyl.
You can order this from any Boots store costing £7.77 for half a litre £10.99 for 2 litres. DO NOT be tempted to purchase larger amounts as even half a litre will last you many months.
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