Dust-OffThings people ask
The same questions arrive most weeks. Here they are with the answers we give.
Is there air in the can?
No. The can holds a gas that has been squeezed into a liquid and sits under its own pressure. Press the trigger and some of that liquid boils back into gas on the way out, which is where the cold and the force both come from.
Why did the can stop spraying properly halfway through a job?
Boiling takes heat, and the heat comes out of the tin and out of your hand. As the can chills the pressure inside it drops and the stream goes soft. Set it down for a couple of minutes, let it come back to room temperature, and it sprays like it did before.
Why does the trigger not move on a new can?
There is a small molded tab holding it, fitted at the plant so a can cannot go off in a box. Snap it off and throw it away and the trigger works normally. It does not go back on, which is the idea.
What comes out if I hold the can at an angle?
Liquid rather than gas. The pickup tube sits at the bottom of an upright can, so tipping it puts the tube into the liquid instead of the vapor above it. What lands on your gear is very cold and it is wet, and neither is what you wanted.
Does the extension straw come with the can?
On most of the line, yes: it clips to the side of the can or sits under the cap. Check the listing for the pack you are looking at, since it varies across the sizes and the kits.
Can I use a duster on a laptop that is switched on?
Shut it down first. Cold liquid landing somewhere it should not is a smaller problem on a machine with no power in it, and a fan that is spinning is a fan you cannot easily hold still.
How long does a can keep on a shelf?
A sealed can does not go off in any way you will notice. Store it upright, out of the sun and away from anything hot, and the last can out of a case sprays like the first one did.
Is a cloth really necessary if I have a can?
For a keyboard, no. For anything with a screen, yes. Gas takes off what is loose and leaves the greasy film exactly where it is, so a display cleaned with gas alone comes out dust free and still smeared.