A solar forge should be able to melt metals. At different heat capacities, it becomes possible to work with more metals. Below is a shortened table of some things that become possible to fully melt at different temperatures (forging temperatures are naturally lower):
| Tin | 232c
| Zinc | 420c
| Aluminium | ~660c
| Bronze | 913c
| Silver | 961c
| Brass | ~900-1025c
| Gold | 1053c
| Copper | 1084c
| Cast Iron | ~1125-1200c
| Silicon | 1411c
| Nickel | 1453c
| Stainless Steel | 1510c
| Steel | 1371-1540c
| Palladium | 1555c
| Wrought Iron | ~1500-1600c
| Titanium | 1670c
| Thorium | 1750c
| Platinum | 1770c
What this suggests is that at a fairly low temperature, it becomes possible to use tin and aluminium cans. At more than double those temperatures, we start to be able to work with steel and irons. The development of this capacity can be a staged process. Working with aluminium would alone open up many doors. Aluminium + Copper would open up more. These could be stages 1 and 2 of ramping up temperatures.
- One possible means of achieving this that has been suggested is the use of fresnel lenses from old TVs. The common-junk prevalence and viability of fresnel lenses should be investigated--they vary both in degree of focus and light gathered. Frensel lenses surely must be viable if we can make them ourselves. Stamping one out from clear plastic, or 3d-printing from clear filament may be possible.
- Inspiration: https://www.youtube.com/watch?v=drE54ctrHBY&ab_channel=GREENPOWERSCIENCE
- Notes: Fresnel lenses might be convenient if they can be salvaged, and they are flat and light, but actually grinding standard lenses may be easier and produce the same result. The fresnel lens does not magically gather more light than the surface area of the lens. These things are worth looking into. As a model for other places, I have to imagine that many locations would not have ready access to fresnel lenses in any case.
- Another possible means of achieving this could be, for example, use of polished steel taken from junk yards to create a loosely parabolic dish focusing light onto a point in the center.
- Inspiration: https://www.youtube.com/watch?v=Q90i31JIQ3M&ab_channel=GREENPOWERSCIENCE
- It should be possible to roughly calculate the amount of sunlight required to be focused per degree of temperature rise per unit of volume. This would be useful to know, to have an estimate of the area a lens would have to cover in order to gather enough light to achieve the higher temps.
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