Aluminum is hard to replace where weight or conductivity per kilogram decides the job, as in long overhead power lines, light reflectors and heat sinks, and easy to replace where it does not, as in carts, frames and cookware. A line of the same resistance weighs about half as much in aluminum as in copper, which is the strongest case for it; for most other jobs, steel, wood or clay serve and scrap aluminum covers the demand.
Part of Aluminum Smelting
The jobs where aluminum’s properties matter most, and which are better served by scrap than by new metal.
The Carrier’s List, Ranked By How Hard It Is To Replace
The carrier names five uses. They differ in how much aluminum itself is required.
| Use | Why aluminum | Alternatives | Verdict |
|---|---|---|---|
| Overhead electrical conductors | Light for its conductance | Copper (about twice the mass for equal resistance) | Strongest case |
| Reflectors | High reflectivity, light | Silvered glass, polished brass | Good, from scrap sheet |
| Heat sinks and radiators | Good heat flow, light, easy to cast | Copper, iron | Moderate |
| Lightweight structure (carts, frames) | Low weight | Wood, steel tube | Scrap suffices |
| Cooking vessels | Light, easy to make | Iron, clay, stainless | Weak case |
The “only aluminum will do” in the carrier’s subtitle overstates it. For nearly every row a village has an alternative that costs less than primary smelting.
Worked Example: A Line Of Equal Resistance
Take a copper line of 10 mm² cross-section, 1 km long.
- Copper volume: 10 mm² = 0.1 cm², and 1 km = 100,000 cm, so 0.1 × 100,000 = 10,000 cm³. At 8.96 g/cm³ (the figure in Copper vs Aluminum) that is 89.6 kg.
- Aluminum for equal resistance at 61% conductivity: 10 / 0.61 = 16.4 mm² = 0.164 cm², giving 0.164 × 100,000 = 16,400 cm³. At 2.7 g/cm³ that is 44.3 kg.
- Ratio: 44.3 / 89.6 = 0.49.
So the aluminum line is about half the mass. That helps poles, spans and transport.
How To Reach The Metal
Primary smelting is not a prerequisite. Why Aluminum Matters and Ingot Casting explain building supply from scrap. Conductors need pure aluminum, which scrap wire can give; alloyed scrap suits castings and sheet. The corpus gives reflectors from salvaged aluminum in Building Reflectors from Salvage, where its reflectivity is 80-90% for polished aluminum. The carrier says 90% or more; the two articles disagree, and I could not settle which is right.
Common Mistakes
- Using aluminum where steel would do and scrap is scarce. Save it for the cases above.
- Connecting aluminum to copper without the proper terminals. See Copper vs Aluminum.
What’s Next
- Learn next: Ore Processing - the first step of primary production
- Combine with: Key Properties - the numbers behind the table