What is pot metal? It’s a catch-all expression that covers spreading parts out of nonferrous metals. Usually as soon as the expression is used, it describes pieces of unknown or possibly questionable manufacture. However there are advanced processes, such as diecasting, that autumn into the category of pot metal.
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Pot metal originated indigenous the practice of gathering all accessible nonferrous metals and melting them right into a pot because that casting. Any process that involves casting nonferrous steels is technically pot metal, though the expression usually describes a much more haphazard composition. Outside the prototyping, that is still supplied for make toys, trinkets, and cheap jewelry.
These vintage numbers are occasionally referred to together pot metal, as result of their uncertain composition. Note exactly how they space not as in-depth as an ext recent figures cast out of pewter would be.
Generically, “pot metal” ad to any mixture of nonferrous metal. In the 19th century, the was generally a mix of generally copper and lead, with smaller quantities of steels like tin, cadmium, zinc, antimony, magnesium and aluminum. Contemporary pot metal is typically a mixture of generally zinc and also other metals, yet the formulations are nonspecific.
Before plastics became common, pot steel toys were the equivalent of cheap plastic playthings today. Plastics have largely displaced pot steel in playthings in current times. However pot metal remains in usage in applications wherein plastic is impractical. Cheap jewelry, for instance, is made of pot metal. The locknut on kitchen sink is usually made the pot metal too, because it won’t rust.
How pot steel works
You deserve to think that pot steel as an early type of recycling. It occurred in factories, but also could occur at a smaller scale, even in a home workshop. Workers would conference up whatever available nonferrous steels they might find, climate melt them down for casting parts. This might even involve scan the floor to gather up steel dust, and emptying pockets trying to find candy or gum wrappers. Some little quantities of iron could incidentally finish up in the mix, however too lot iron would certainly raise the melting temperature as well high. Mixing in larger quantities of lower melting-point metals, such together lead, tin, and zinc, would lower the melt temperature to a an ext usable level.
The exact composition didn’t matter much. Mixtures of metal tend to melt at lower temperatures than pure metals. You’ve observed this if you’re acquainted with soldering. The solder melts in ~ a lower suggest than the copper or tin you’re soldering to. Her soldering stole can’t melt the copper, but it will certainly melt the solder. And also if part solder appears to melt much easier than others, you’re not imagining things. Lead-free solders melt at a greater temperature than lead-bearing solders. And solder consisted of of 63% lead/37% believe melts at a lower allude than the more common 60% lead/40% tin composition.
With pot metal, what mattered most was gathering sufficient material, and also getting the melting suggest low enough. Litter in sufficient material and it would gain there eventually, pretty lot at random.
Advantages of pot metal
The benefit of pot metal is the it’s an extremely cheap, since it involves material the otherwise would have actually been wasted. In work of old, that was impossible to t to win the price of sweeping the floor and emptying pockets. It eliminates the need for any kind of sorting or refining, since impurities climb to the height as it melts. They might pour off the impurities, dubbed dross, then start spreading parts. It’s very efficient, as lengthy as the demands for the perfect product aren’t very strict. The locknut top top a kitchen sink is a good example. It demands to organize a thread, no rust, and also survive host up to huge sets of pliers. Every little thing shade the gray it end up gift is fine, that doesn’t have to be any details color. And if the end up is a bit rough or uneven, nobody will notice or care.
Since it’s cheap and easy to mix up and work with, it’s good for prototyping and also experiments to test concepts. Climate if it works out, the item can be manufactured with a much better material.
Disadvantages of pot metal
Sometimes cheap random metal is good enough for the job. Yet newer production methods that allow for a finer level the detail, such together diecasting, have much more specific composition requirements. Presenting trace quantities of lead into the mix can cause these alloys to rest apart in a relatively short size of time, sometimes only 3-4 years. Suddenly, the exercise of scan the floor come get more material for the mix walk from gift smart and resourceful to gift destructive.
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The stormy cooling point of the material can trap waiting pockets in the casting, leading to fragility or brittleness. Once price is the main consideration, that might be okay. Yet when durability and also repeatability room important, much more sophisticated methods, such together diecasting, are more appropriate.