Hypothesis: A cheap rocket motor igniter can be made out of steel wool and black powder.
We tried out the concept by sending an electrical current through some steel wool and got it to ignite at 3 Volt and 5 Ampère.
Power required = 3 Volt * 5 Ampère = 15 Watt
Readers note: steel wool requires quite some energy to get it to glow red hot and ignite. But 15 Watts is easily reached by using a powerful battery such as an 28 Volts battery of an electrical hand-held drill.
Here's the video of steel wool igniting at around 15 Watts:
Then we arranged the steel wool on some paper tape:
Poured black powder on top and simply wrapped it up.
We made 3 versions:
- test #1: a black powder igniter with paper tape, pictured above
- test #2: a black powder igniter with a plastic straw
- test #3: a black powder igniter with a post-it, rolled up and taped together
Test #3 contained a bit too much black powder than strictly necessary, check out the video. It will be discussed in the"Safety Improvements" section below!
- Small amount (2 g) of steel wool: 0.2 euro
- Small amount (10 g) of black powder: 0.6 euro
- Copper wire (10 cm) to connect to the steel wool: 0.2 euro
Total price per igniter: around 1 euro
The hypothesis has been validated; a cheap rocket motor igniter can be made out of steel wool and black powder. The igniter has a power requirement of around 15 Watt.
To stay focused on safety, we'll conclude every session by trying to find at least one safety improvement to be implemented.
Next time we'll be sure to fixate the camera and leave it unmanned. That will give us a better view of the reaction from close by and will keep us safe at the same time.