Packaged air

As part of my job, I unpack anywhere from half a dozen to twenty or thirty packages a day. They range from small cartons that weigh a few ounces, to large servers and color printers that I can barely move without a hand truck. The one thing nearly all of them have in common is that they contain a lot of air.

In some cases it’s very obvious, like the boxes that contain memory sticks. The smallest carton our computer vendor uses is about 3/8 cu ft, and the memory stick comes in a package so small it often slips beneath one of the flaps of cardboard at the bottom. The rest of the box is filled with air pillows, which I slash open with a box cutter (and try not to slash my other hand in the process) before putting them in the plastics recycling bin.

I hadn’t realized it until today, but even those heavy printer packages, where nearly all the space is taken up by either the printer or foam packaging, contain quite a bit of air. It’s just hidden inside the foam. Polystyrene foam (the generic name of the material of which Styrofoam is one example) is over 90% air.

I’ve been doing Google searches about Styrofoam because I need to help Al make a model of a space probe for his science class. He wants to make it cylindrical, not a box shape, so he thought Styrofoam would work well. I have access to a box full of polystyrene foam that has been left for recycling, so I pulled out a bunch of pieces with some curved portions. Now I have to figure out how to cut and shape them to make something more or less cylindrical.

Since I don’t have access to a hot wire tool, which seems to be the preferred method for cutting foam to the desired shape, I will have to settle for using a knife of some kind. I found one forum where someone said he had used a hot iron to smooth roughly cut portions (with wax paper as a protective sheet so the foam wouldn’t stick to the iron). I’m not sure I want to try that, but I might try what someone suggested as he saw me picking through the recycling bin – use nail polish remover to dissolve parts of the foam that I can’t easily cut away.

I’ll probably write a post on how it all works out. But in the process of doing these searches, I came across a very interesting article on the various kinds of material used to pack a protective cushion of air into a box. I’ve seen examples of most if not all of these in the various boxes I open at work. (I don’t know if I’ve seen corn starch peanuts here, but I’ve seen them in previous jobs.)

What I found most interesting was to learn how some of these materials are made. Have you ever wondered how they get the air into bubble wrap? It’s explained in this article. It also tells how to make foam molded to the exact shape of an object, by creating the foam in place, inside the box.

The article also explains the why packing peanuts work so well. I still don’t like them, and I’m always glad when one particular vendor ships products packed with bubble wrap or air pillows instead of a gazillion peanuts. (I’ve thought of telling the procurement analyst to tell the vendor that I’m allergic to their peanuts.) But understanding the physics of how they work makes me a little bit less ill-disposed toward them.

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