What would McGuyver use Mylar for ?

Mylar is more than a fashion statement

Recently while packing for an expedition I was going through my Adventure Medical Kit and started thinking about multiple uses for some of the items in the kit .

I have always thought the mark of a good explorer is being able to take an item or peice of equipment and use it for a host of varying situations. I guess the example most people think about is duct tape. It is the material that is the holy grail of wilderness versatility however I started looking at my shiny space blanket (Mylar sheet) and I thought what would what might MacGyver use Mylar for?

McGuyver the patron saint of ingenuity

First of all Mylar sounds like an ominous, extraterrestrial substance, but it is actually present at most birthday parties you go to. Mylar is the trademark name by Dupont, and it is basically the silver stuff that party balloons are made of or computer parts are stored in or even food is stored. Most people will recognize Mylar as the thin, silver blanket that they hand out at the end of marathons or the “space blankets” that you find in your Adventure medical kit.

Marathoners with Mylar blankets:Boston Globe

Mylar has been around a lot longer than most people think, and even Wikipedia falsely says that it was invented by the space industry in 1964. On the contrary, it was actually developed by Dupont Mylar in 1952 when it grew out of the development of Dacron, and was first used by NASA for their Echo Satellites in 1960.

So what might MacGyver use Mylar for?
First, he would use it for an emergency blanket; he would know that it works the same way a thermos does to keep heat and reduce heat losses in a person's body due to thermal radiation and convection.

Better sad than dead.

In the same manner that it keeps a person warm, sheets of Mylar covering a tent’s inner walls with the shiny surface facing inward, keeps a tent warm. It reflects body heat back into the tent, warming the interior more efficiently.

Mylar can keep a tent warmer even on the North Pole

On the other hand, in an extreme heat situation, covering the outer walls with the shiny surface facing outward will reflect the sun's heat away from the tent, cooling the interior more efficiently. Using a sheet of Mylar will protect the body from heat as it will reflect the suns heat.
However, it might not be a good idea to wrap ones self tightly in Mylar in hot weather because body heat would get trapped by the airtight foil, and you would be the equivalent of a baked potato in an oven. Seems counterproductive no?
MacGyver would also use Mylar to fashion a tent or tarp for protection when the elements got the better of him.
In addition, he would also probably make a hot air balloon or create a kite to aid in rescuers with visual ques.
Since Mylar can be made into balloons it can also be used to make water or food storage bags. Mylar is incredibly heat resistant but you probably cook food or boil water in it for water purification.

Solar oven: Project Surya

With good sunlight Mylar can be woven in to parabolic baskets and made into solar cookers that can be used to cook food or pasteurize water during emergencies when other fuels and power sources may not be available.

Although it is used for solar sails in outer space, in a pinch it could also be used to make a makeshift sail for a canoe or a small boat. A word of caution: Though Mylar is a very strong material, it rips quite easily, and should be avoided when trying to catch gale force winds.

Mylar can be easily made into glacier glasses because you can see through the material in very bright light. Naturally, MacGyver would probably be traveling to a destination with a solar eclipse and would also use it as an inexpensive solar eclipse viewer. Care must be taken however because invisible fissures can form in the metal film, reducing its effectiveness.
Obviously, in an emergency situation, it is a big help if you are found right away. Not only can a sheet of Mylar be used to signal rescuers, but in true MacGyver fashion, he would know that radar waves can be reflected by certain substances such as aluminized Mylar, a lot like the way that light is reflected by a mirror. You want the surface to be hard so it doesn't distort and affect the reflectivity for the radar waves. Think about looking at yourself in a nice, clean, smooth mirror. You get a good representation of what you look like because the light waves aren't redirected by surface irregularities.

The ultimate party baloon

Though metalized party balloons aren't great radar reflectors, they'd be much better than nothing in an emergency. But then again, McGuyver might just keep them as welcome balloons—if he couldn’t be in control of the situation, at least he could enjoy the spectacle!