Back to Metal!

Plastics are a pervasive feature of modern life. If you take a look around you as you are reading this, you would find more plastic components than metal. Plastic is so cheap to produce and to manufacture, most of the throwaway items that you get is also made of plastic. However, recycling plastic is entirely another issue. Since there is such a large variety of plastics in the market, it cannot really be recycled, and has to be buried in landfills.

How can you deal with the above situation? First of all, when offered some gadget or knick-knack which is of questionable value to you, just say no. If you use a plastic pen, make sure you get one without the rubber parts so that you don’t have to throw it away after a couple of months when it starts to rot. If offered some plastic bags to carry your purchase, see if you can carry it without it. Many machines now come with rubber bushes rather than metal springs. These need frequent replacement, which is a hassle and a drain on your wallet. If you have a choice, go for the solid metal one.

Plastic movable components are really a recipe for disaster. USB drives of the slider type are a good example. Perhaps all is not lost–many systems can have the plastic parts replaced with metal. Of course, this implies a good machining center to get the tolerances required.

This brings me to the main idea in this post–namely, replace as many plastic parts with metal! What if you have to throw away a metal part, you ask? Well, feel free to do so–there is always someone who can make a living off that scrap. It is actually profitable to extract metal from scrap and reuse it.

Another material which can replace plastic is wood. Now, wooden parts are not so easy to manufacture as plastic ones, and this would definitely limit the kind of products which you could avail, but every little step is important. Note, however, that when wood is used to build something in these modern times, there are add-ons that you would not have expected hundred years ago. Wood is treated with chemicals which are not exactly environment friendly to prevent it from drying out too fast after cutting (fast drying causes splits). The recommended material for coating wooden furniture these days is plastic! So you can’t really throw away your broken wooden furniture or burn it—it has to be recycled like plastics.

Many metals can be recycled almost completely—the lead in storage batteries comes to mind. With the current level of inflation, it would not be surprising to get more money out of a well maintained battery than what you originally paid for it.

One way you yourself can reuse metal is by melting it. One useful metal which has really low melting point is aluminum. It melts around 1400 F, and is lightweight and corrosion proof. Until about a 100 years ago, it was a rare metal, but now it is ubiquitous and cheap. Aluminum sand casting can produce many structural parts for day to day use.

Renewable Energy

There has been many an attempt made to produce the so called renewable energy. The machines required for this need to have certain characteristics–namely, the ability to work without wear and tear for a long time. An automobile or a lawn mower engine, with its limited duty cycle will simply not do. A modern car is designed to work for about 4000 hours between major overhauls.

Eco-Friendly Vehicles?

Another trend in hyping of these new fangled machines is the undue importance given to the most “eco-friendly” component of the system.

Hybrids

A hybrid is considered more environmentally benign choice compared to the standard gasoline engine. However, consider this–the hybrid is really two machines in one, and instead of driving a single car, you are now simultaneously driving two! The environmental impact of manufacturing a single car would be enormous. In fact, several sources give the amount of money that you might spend on gas in the couple of years you own a car–considering a reasonable distance of 30,000 miles, you would spend less than $5k even at the highest prices. This means that the cost of the vehicle, which is mostly manufacturing cost, would be about an order of magnitude larger than the fuel cost. Since the energy cost is significant factor in determining the manufacturing cost, this is definitely something to be considered during purchase.

Regenerative Braking

Another much touted feature in such cars is regenerative braking. Whereas you need energy to accelerate your car, you can theoretically get it back when braking. These cars claim to have brakes that will feed the energy into batteries while braking improving fuel efficiency. However, this needs some qualification—it is only available if you brake gently. In that case you might

Historical Energy Sources

A common sight in the middle ages was the truly renewable energy source of a dog wheel. A small dog would be made to run inside a giant hamster wheel. Now, we make jokes about things powered by hamsters, but the few watts produced by a small canine was very useful in those days. Farmers used small animals like sheep to run small machines, the ones that did not require “horse power”. Here the animal walks on an inclined tread mill, which drives a small machine.

The earliest machines were powered by water, and it was used to power fountains and carry water from a lower level to a higher level. Hopefully, the source of water was a stable one, like the palaces of Louis XIV in Versailles. Some of the kingdoms in south east Asia were not so fortunate, the river having shifted course, rendering their elaborate constructions useless.

Inherent Inefficiencies of Local Power Generation

Small machines inherently have greater frictional resistance when operated in a piston cylinder arrangement. Large machines have their own problems, mainly the manufacture of such large cylinders and fitting pistons. However, since the surface area per unit volume for the smaller machines were much larger, the frictional losses were larger too.