Introduction: Cheap and Easy Solar Kettle (to Be Used With Solar Funnel or Other Reflectors)

This project is intended to be used with a solar funnel or other reflector system. I was looking for something that could be portable and durable for easy use and travel, but not so expensive that I would be heartbroken if there was an accident. I will be posting a packable solar funnel project as well soon that was designed for use with this kettle. But you can learn about the basics of the solar funnel here:

The concept behind the solar kettle is simple. The black inner container absorbs the heat from the solar radiation. The outer glass jar protects the inner container from losing heat due to convection from the air while the transparent glass still lets the light through.


1 aluminum water bottle (they have been selling them more and more as plastic alternatives)
1 quart sized mason jar with lid
black paint
silicon sealant
epoxy clay
tin snips

Step 1: Prepare the Mason Jar Lid

Cut a hole on the lid of the mason jar the size of the opening of the water bottle.
To do this you will need to trace a circle the size of the opening in the lid. In the center of the lid, I punched an X with a screwdriver and mallet and used the tin snips to cut away the metal

Step 2: Paint the Water Bottle

I had a bottle of black 2.0, but any matte black paint should work. you can hit the can with sandpaper first to help the paint adhere better.

Step 3: Assemble the Kettle

I used the silicon sealant to glue the bottle to the bottom of the mason jar, and screwed the mason jar lid over the top. The gaps between the bottle and the lid were filled with the epoxy clay.

I also punched a hole in the lid of the bottle. This is a safety feature as it allows pressure to vent out when the water heats up. Without this, if the lid is screwed on top tightly, the pressure could cause the kettle to blow.

Step 4:

Use with a solar funnel (or other reflector system)
When I field tested the setup using my gosun go as a comparison, it lagged behind the gosun by only about 5 degrees