Introduction: Packable Solar Funnel

This was the solar funnel I made to go along with my Solar Kettle

It is based off of the standard solar funnel design but it was modified to be disassembled into smaller pieces to make it easier to pack and carry.


2 pieces of poster board at least 22"x22"

1 Mylar emergency blanket

2 rolls duct tape


self-adhering Velcro

2 tent stakes

Step 1: Measure and Cut the Cardboard

The original template did not come through in the photos, so I played with an editor to try to make it clearer.
the 4 pieces are made from 20"x10" rectangles with interlocking tabs. On the long edge, I made the tabs 1" high and 2" long, and on the shorter edge the tabs were 2" by 2". Make sure tabs interlock, so you will have to reverse the pattern of the tabs on the short side for the second set of rectangles.

On the edge of the bottom 2 pieces, cut a half circle with a radius equal to the diameter of the pot you are going to use, My solar kettle had a 3 3/4" diameter, so the radius of the circle cut out was 3 3/4".

Step 2: Cover the Poster Board With the Mylar

There is a shinier and a less shiny side to mylar. Place the shiny side down and the piece of cardboard on top.

1. Fold the Mylar over the edge and tape it in place

2. Turn the piece over and apply a small layer of glue to the first inch or two of the paper, and then pull the Mylar over it, trying to get it as flat as possible.

3. Repeat the above step until the whole side is glued into place.

4. Fold the Mylar over to the other side and duct tape down to secure

Step 3: Add Attional Straps Made of Duct Tape

So I forgot to include a bottom set of straps on the initial cardboard design. So add them with a few strips of duct tape folded over onto themselves.

Step 4: Cover the Back With Duct Tape

Add layers of Duct tape to the back of the panels. This makes the panels a bit more durable, and make the whole project look cleaner. I used the wood grain decorated duct tape, but you can use any color or design you want.

Step 5: Add Velcro

Attach the velcro to the tabs and the locations on the panels where they connect. To do this, I found it easiest to just first interlock the panels, stick the two pieces of velcro together, attach them to the tab and then press them into the panel.

After that, pull the bottom edges of the panel together and apply the velcro to the bottom tabs

Step 6: Assemble and Use

The whole system rolls up nicely around the solar kettle for easy trasport.

When you are ready to use it, assemble the panels and interlock all the tabs, and when you secure the bottom tabs together, you will get he funnel shape.

The two small camping stakes easily slip into the bottom tabs so that it can be staked down and secured.

When I did my test run, I also ran it against my Gosun Go for comparison. The Gosun seemed to stall out at about 200 degrees F, where the solar funnel seemed to stall at about 196 degrees F. So neither got a good boil that day, but given that this system costs a fraction of the cost to make, I think it did well against it's more professionally made cousin.