Concentrated sunlight can solder (230-350°C), braze (600-900°C), melt aluminium (660°C), make steam and distil water, all with no fuel, because a mirror lets a small target reach several hundred degrees. The limit is power, not temperature: a 1.8 m dish delivers about 1.5 kW, so it works small pieces slowly and on clear days only.
Part of Concentrated Solar Power
High-temperature solar applications use a concentrator’s focus as a fuel-free heat source for metal, steam and water treatment.
Temperature And Power Are Different Limits
A concentrator’s ratio sets the highest temperature the target can reach; its mirror area sets how much heat per second the target gets (Concentration Ratio & Temperature). The parent page quotes about 1.5 kW from a 1.8 m dish, comparable to a small propane torch. That is plenty to solder a joint and slow for melting a kilogram of metal.
What It Can Do
- Soldering (230-350°C) and brazing (600-900°C): thin work at a precise spot, no flame and no smoke (Metalworking & Soldering).
- Melting aluminium for casting in small batches (parent page: 660°C).
- Steam for a small engine or for process heat (Steam Generation).
- Water distillation and boiling for purification (Water Purification).
What it does not do well: anything needing a steady, controllable flame, anything on a cloudy day, anything that must run at night, and large masses of metal. For those, the forge and charcoal remain better (Metalworking).
What You Need
- A built, tested concentrator (Accuracy & Focus Testing)
- A way to track the sun (Tracking Systems)
- A fireproof work platform at the focus
- Tongs, crucibles, flux and a heat-resistant glove
- Eye protection and a shade for the operator
- A cover for the dish
Method: Plan A Solar Work Session
Step 1: Choose the job by temperature and mass: thin and low-melting tasks first.
Step 2: Set up in the morning, check the aim, cover the dish.
Step 3: Work in the clear hours around midday, and keep everything else clear of the focus.
Step 4: Put the cover on before leaving the dish, even for a minute.
Common Mistakes
- Treating 1,000°C as a promise. The temperature is available only at the focus and only on a clear day.
- Large pieces. They drain the focus’s power.
- No cover or stow plan. The focus sweeps across anything nearby as the sun moves.
Safety
Concentrated sunlight ignites at once and blinds without pain
The focus ignites wood, cloth and dry grass immediately, and it burns skin; the eye cannot sense retinal injury as it happens, so a split second of looking at the focus or at a bright mirror reflection can leave permanent damage. A tracking concentrator left unattended sweeps its focus across whatever is nearby. Never look at the focus; keep people, animals and combustibles away; cover the dish whenever you leave it; and wear dark eye protection that blocks infrared when working near the focus.
What’s Next
- Learn next: Metalworking & Soldering — the most common solar-forge tasks
- Combine with: Steam Generation — heat with a receiver pipe