Jefnie Savage (l.) and a worker at Pupkewitz

First of all, go to your local hardware store and organise corrugated roofsheet cut-offs. We went to Pupkewitz in Windhoek and the manager there was more than happy to supply us with 10 sheets. They should be the size of DIN-A4 or slightly bigger.

Now you are ready to produce the installation template:

1. Cut out two circular templates from paper. The bigger one (outer) should have a radius of 5.1cm, the smaller one (inner) of 4.8 cm.
   

   Circular paper templates

2. Use the bigger template to draw a circle onto the corrugated iron sheet.
3. Now draw the inner circle onto the corrugated iron sheet. Make sure that both circles have exactly the same center.
4. Using a manual drill make a hole in the middle of the circle.
5. Use a pair of tin scissors to cut out the inner circle.
6. Make 90 degree segments 2-3mm wide between the inner and outer circle.
   

   'Teeth' - cut and bent upwards

7. Cut the segments with the tin scissors and use pliers to bend them upwards – like teeth. These teeth will prevent the bottle from falling through the roof.
   Make sure that the teeth are bent exactly on the line of the outer circle.
8. [optional] Use a grinder to cut off unnecessary parts of the corrugated iron sheet that you will not be using. The size of the template does not need to be bigger than a DIN-A4.
9. Drill a hole into each corner of the template. These holes will be used to fix the template to the actual roof with rivets.

With the help of this iron the template the installation of the solar bottle in the actual location can be done in twenty minutes. For the installation of the soalr bottle into the roof follow these steps:

1. Mark the center of the template onto the roof. Make sure the area that you’ve selected is not shaded during the day. Otherwise the brightness of the solar bottle will be reduced dramatically.
2. 

   Template riveted onto roof

   Use the bigger circular paper template (s. previous step 1) to draw the outer circle onto the roof from the inside.

3. Drill a hole at the centre of the circle.Then cut out the circle with the tin scissors.
4. Now get onto the roof and use the template as guideline to drill the four corner holes  into the roof to rivet the template.
5. Clean the roof surface.
6. Apply silicon to the back of the template.
7. Pop rivet the template to the roof.
8. Put a two litre soft drink bottle filled with a bit of water into the center hole.
9. Fill up the bottle with water. Add a bit of bleach to avoid the growth of algae.
10. Seal around the bottle with silicon.

That’s it.

Installed solar bottle from the outside.

Solar bottle in action.