Coil Gun Mach 1

• Project Start Date: April 2006
• Project End Date: July 2006
• Current State: Completed

This is my first attempt at a coil gun.

• Switch: 2x 600V 3300A (non-repetitive pulse) SCR
• Capacitor Bank: 24x 330V 80uF Capacitors
• Total Energy: 209.1J
• Target Efficiency: 3% (6.27J of kinetic energy)
• Projectile: Steel rod 30mm long, and tipped
• Projectile Mass: 15g Target Velocity: 28.9m/s (104km/h)

Capacitor Bank

The capacitor bank was built from capacitors scrounged from used disposable flash camera’s. I got the cameras for free from a Kodak photo processing store just by asking nicely :-). Each camera has one 330V electrolytic capacitor ranging from 80 to 120uF. These can easily be unsoldered and hooked together for an el-cheapo capacitor bank.

Disposable cameras from a Kodak processing store.

The circuits inside the disposable cameras.

330V 80uF caps from the cameras.

Assembled 1920uF 330V capacitor bank.

I don’t want to touch it.

The finished cap bank.

The Coil

• Wire Diameter = 1.00mm (18AWG)
• Coil Resistance = 0.3Ohm
• Coil Inside Diameter = 12.5mm
• Coil Outside Diameter = 30.0mm
• Coil Length = 30mm

The coil was made with enamelled copper wire and wrapped around a coil former. Two slotted metal sides contain the wire and provide some structural strength. The coil was covered in two-part epoxy to hold the wire in place. The coil is designed to be slipped onto the projectile tube.

The cardboard core and two slotted side washers. The slots prevent eddy currents from forming and wasting power.

The coil former assembled.

The coil completed, ready to slide on the barrel.