Student creates amazing solar powered rock tumbler!

Congratulations to Bella in 8T for her amazing project on creating a solar powered rock tumbler to polish rocks! Please see below a write up from Bella plus some photos of the design/process/finished product.

A huge well done from all at Fairfield.

Bella’s rock tumbler write up:

I was talking to my uncle one day about how I wanted a rock tumbler to polish stones, and we wondered if we could make one.

We thought about the amount of electricity it would use as it has to tumble constantly for weeks to polish the stones, and decided our project would be solar powered.

My uncle was up for making the plans, as he loves to invent and build things. He works with solar panels for his job, and managed to get a lot of our equipment from his workplace.

He explained the plans to me and we worked together building it in his garden, and assembled the last stages of it at my house. Here is a list of the materials we bought to build the mechanics of the rock tumbler:

Tumbling Barrel – £11.95
Motor – £21.99
Hosepipe (optional, but helpful, provides grip for the turning rods) – £1.64
Shaft Coupler – £6.49
Pillow block bearing (x4) – £9.34
Spade receptacles and wire – £6.99

Recycled (R) or borrowed (B) materials we used to build the mechanics of the rock
tumbler:

50 watt solar panel – B
Victron 75/10 smart solar charge controller – B
12 volt 13ah SLA battery – B
2.5mm hookup wire – B
1inch strips of steel – B
MC4 connectors – B
Plywood, Hinge, Screws (for the box containing the tumbler and motor) – R

We also needed to buy grit in 4 different grades of fineness to polish the rocks in different ways, the pack cost £16.50, for reference our pack included plastic pellets, required to fill
in space in the barrel, but apparently you can use walnut shells as an eco-friendly alternative, I am reusing the plastic pellets).

This led to the total cost being £74.95. This may seem more expensive compared to a mid range tumbler for sale on the internet (£50 approx), however, in the long run our version
costs less as it costs no money to run. It uses no electricity, just sunlight. And even on cloudy days it still runs into the evening! Additionally, if a component wears out or breaks, I
can replace it.

I have really enjoyed the experience of building the rock tumbler and using it too. Seeing how different stones and materials have reacted to the tumbling process is really
interesting.

I hope you feel inspired by this in some way!