Mike's models: Rolling ball sculpture No.1

Rolling ball sculpture (RBS) No.1 using a helical lift mechanism.

After finishing the pinball machine, I started looking around for another long-term project.

I found a lot of rolling ball sculptures on YouTube and they looked an interesting challenge so in I dived.

This is an example of an RBS.

It is made mostly from 1.6mm copper wire. The tracks are joined together by soldering.

Using a soldering iron to join the pieces together is a bit laborious and the soldering iron tips need constant cleaning and wear out quickly.

For this reason, I decided to build a resistance soldering unit. A good video explaining its usage is here https://youtu.be/AzvHfxxzqh8

These units are very expensive so I decided to build my own using an old microwave transformer and an old power supply case that I had lying around.

I got the second-hand transformer from an appliance repair guy for R50 ($2.76 - £2.17)

I then removed the filament and secondary windings.

I replaced them with 3 turns of 10mm wire to form a new secondary winding of 3.3v and very high current. This was then mounted in the case. The incoming 240v was wired through a foot switch to the primary coil of the transformer.

One side of the new secondary coil was wired via the mains earth to a clamp.

The other side of the coil was connected to a homemade probe.

The probe had a 4mm carbon rod tip, push fitted into a length of square brass tubing, fitted into a length of wooden dowel with a sleeve of 20mm pvc conduit.

The carbon rods were obtained from the centres of cheap AA batteries.

Building the RBS

I started off by sourcing the motor and power supply. The motor was a 12v-10rpm from Timu. The power supply was 12v-2A from Takealot. I bought 2 of each.

I bought a flexible 6mm connector for the motor drive output, locally.

I had some oak board which I used for the base of the RBS and into this I fitted the motor and wired it via a switch to the 12v power socket. I had some mp3 players spare so decided to add sound. The mp3 player operates on 5v so I made a simple 5v regulator circuit which worked off the 12v motor supply via an on/off switch. The player was connected to a small 8 ohm-0.5w speaker, all mounted in the base.

The first stage was to make the vertical ball lift and outer frame.

Before continuing with the tracks, I started making the various elements such as flip flop switches, spirals and loops, etc. These were all tested before deciding where to put them in the sculpture.

Ball return.