Saturday, 18 January 2014

DIY Freezing Kit

DIY Freezing Kit

Today I want to give you the super power to freeze things. I'm going to show you how to make your own version of a commercially available product, with the only difference being yours will be cheaper.

This product serves one purpose, but hopefully the information gained within the article will inspire you for other applications.

Start by watching the video!


This information is for education and entertainment purposes. Do not use in a dangerous or illegal way. Use of any or all information from this article is done so entirely at your own risk. Stay safe.


Materials


Materials Needed:


  • Can of air/air duster (it's called "air" but it doesn't contain air)
  • Pipe lagging
  • A bin bag
  • Some cable ties*


Tools Needed:


  • Junior hacksaw* (or other cutting tool for cutting lagging and cable ties)


Lagging

So we’ll start by first cutting a piece of lagging about six inches long (15cm) and putting that onto the pipework we intend to freeze.

Wrap bag around foam

Then we wrap our bin bag around the lagging to make a protective jacket.

Freezing Kit

Add Straw

Now cable tie both ends, leaving one slightly loose while you feed in the air cans flexible straw.

DIY Freezing Kit

Once it’s in position you can tighten the cable tie the rest of the way.


Now just reattach your canned air and start spraying, making sure the can is upside down.

Frozen pipe

While we wait for the ice bung to form I want to go over how this works.

Why does canned air freeze when upside down

Although these dusters are often called canned air, they don’t contain gas normally found in the air. The one I'm using contains Tetrafluoroethane. Inside the can we see it’s in both a gas and a liquid state, it’s the pressure inside the can that keeps it a liquid. When you press down on the top, it opens the valve and allows gas out. This drop in pressure allows the liquid inside to boil, in turn making more gas and providing the pressure to force the gas out.

Air Spray as Freezing Kit

Turning the can upside-down gives us access to the liquid instead of the gas. As the liquid leaves the can it almost instantly boils in the air and as it does has an endothermic reaction absorbing the heat from anything it’s in contact with.

DIY Freezing Kit

Back at the pipework our ice plug is in place, I've removed the tap I had on this end and as you can see it’s holding the water back.

Warm up pipe

When I heat the pipework, the ice slowly melts and allows the water to flow again.

Sponge
DIY Freezing Kit
If you don’t have any spare lagging you could use a sponge instead.

Mike in Ice

Just remember with great power comes great responsibility - please don’t abuse this information.

Tips:

  • Always make sure the pipework is cooled before use. Trying to freeze heated pipework will not work and will waste your spray. If working in a warm room that can't be cooled (like in summer) you'll have to use more spray than usual and the amount of time the ice plug will last will reduce.
  • Make sure the pipework is free from paint at the point of use, as this will prevent the kit from working.
  • For 15mm (1/2") pipework I use roughly a quarter of the can, different sizes and different materials (like plastic pipe) will take different amounts.
  • Don't use in confined spaces or where there is poor ventilation, as you don't really want to be breathing in the fumes.
  • Don't use heat too near the kit as you should avoid flames near the vapour and you don't want to melt the ice bung.
  • Wait 5-10 minutes after spraying the pipework to allow the "ice plug" to form properly.
  • Ideally you should freeze horizontal pipework. If you have to freeze vertical pipework you will have to tape the bottom to avoid liquid escaping.
  • If liquid is escaping the sides pause for one minute and ensure the cable ties are tightened.
  • Avoid using the freezing kit too close to the area you are working on, as you don't want to melt the ice if your soldering or dislodge the ice plug with too much movement.

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