Solar Smelter

Fairly high on my to-do list is building a solar smelter. The first one will be used to melt down aluminum to cast a second one from aluminum. The first one will be lined with potato chip bags and whatever other aluminized mylar or other shiny stuff I can scrounge up. I figure having cast (and polished) aluminum reflectors with allow more portable/transportable use as well as being longer lasting than potato chip bags. It will concentrate enough heat to melt metals, rock, and glass. What would be really cool is to adapt the idea to make a solar powered subterrene to melt tunnels into rock/earth.

Welcome to Permies! I want to try using a large Fresnel lens to melt glass - your project is much more ambitious. Please take lots of pictures and keep us posted as there are plenty of people here who like to learn about useful, solar powered equipment.

Sounds like someone's been watching "The Core" on repeat. The problem is the lack of unobtainium.

I love the idea of a solar smelter. One of my long-term projects is going to be one that works reliably enough that, in an Ontarian summer, one could use a solar smelter to cook glass from its raw components. My much better half is a glassblower, so a glass furnace powered exclusively by the sun would be a huge money and time saver.

I would love to be able to smelt scrap metal and glass. I think I would draw the line there. I have no real need of a lava machine.

Though I have to say, I think this is much more likely to be of use in the tropics. Remember those mirror-based solar thermal towers, and how they're all in deserts that see more sunlight than they ever will need.

-CK

Please keep us posted!

If you could build a solar kiln that was capable of slumping glass bottles or melting a collection of glass into a glass block, it would be of great interest and utility to this community; we've got a very long running discussion of how to recycle glass with permaculture methods to which such a device would be very relevant.

Yes, but this is a permaculture site.

We’re not looking for the fastest, easiest, most effient way. That usually involves unsustainable methods and unaccounted-for externalities.

The energy budget for modern kilns and forges is dismaying to permaculturalists. It doesn’t matter if you have your own or hire the work done cheap; you’re using a ton of fossil fuel.

There is a sustainable path using charcoal sourced responsibly, but it is laborious and requires access to enormous forest resources.

There are a host of technical challenges with solar forges, kilns, and smelters. But there are solid reasons for permaculturalists to be interested in such designs.

Dan Boone wrote:

There are a host of technical challenges with solar forges, kilns, and smelters. But there are solid reasons for permaculturalists to be interested in such designs.

 One of the reasons I agree with Dan, is that even if the goal of a Solar Smelter isn't achieved, the ideas we come up with could end up being the solution for a different problem. History is full of experiments that failed in their original purpose which got re-purposed into useful products/techniques. Too often there is pressure to "get the right answer" when in fact, learning from our mistakes is often the greater reality. That's why I really appreciate it when posters give us updates on things they try even when their update says - I'll never try this again!

LOL, too true!

I can’t tell you how often I see some thread where the experimenter reports “this failed; I would need a literal ton of waffle sponges to make it work and they are expensive on my island.”

Whereupon somebody else posts “ZOMG hold my beer, I have a whole barn full of waffle sponges, this is going to be so awesome!”

This is definitely a worthwhile project, if a challenging one.
Back in 2014, The Atlantic published an article about a solar furnace built by a group of researchers at Valparaiso University in Indiana. They used a series of mirrors, the whole array measuring 20'x20', and achieved temperatures that could melt glass. It's possible!
Perhaps this could be achievable with a smaller set up if more highly insulated, in such a way that the smelting box takes longer to heat up, but ultimately reaches the same temperature? I'm no physicist, I'm afraid. DIY'd reflectors made of mylar film might end up being less efficient than the high-end mirrors they used as well.

check out greenpowerscience on youtube

https://www.youtube.com/watch?v=drE54ctrHBY

We did some experiments yesterday with melting glass:

https://permies.com/t/40/1072/glass-bottles-jars-roofing#953815