Meanwhile at JustAddSharks HQ, the evil geniuses were watching some great videos on line of people using their homemade portable 1W laser diodes to pop rows of 100 balloons. We thought, "1W, pah! We've got a 30W laser tube sat there doing nothing, imagine how many balloons we could pop with that thing".
Turns out we were not as good at popping balloons as we first hoped but we did learn quite a lot along the way and we thought we'd share that knowledge in case anyone else wants to take up the challenge. As long as you learn and have fun along the way it's all good right?
As you've no doubt seen from the video by now we popped our way happily through 25 balloons, it gets a little bit slow at the end but it gets through them. The arrangement was really very simple. We took a standard 30W laser tube and power supply, connected the two together, connected up a water pump to cool the laser tube (although there was minimal chance of it overheating in that time). The balloons were all stapled to a baton to hold them in a row and the laser fired.
Now, if you want to try this and you want to be more successful than us you can learn from our findings/mistakes.
- Inflate the balloons fully and evenly:Stretching the rubber of the balloon tight means you have less rubber to burn through before the balloon pops, even sized balloons mean that you'll hit them all at the same point, square on, where the rubber is thinnest.
- Fix the balloons securely onto their mount: If the balloon moves while the laser dot is on it, the laser will take longer to heat up the rubber and pop it. The other videos I've seen have the balloons each mounted individually into plastic cups with the nozzle pulled tight through the bottom of the cup. The cups are then weighted down with water. This seems to be very effective at holding the balloons still.
- Focus the laser beam with an appropriate lens: This was probably our biggest mistake, our dot starts with a 2mm diameter and gets wider from there out. This means only a fraction of the power of the beam was hitting the balloon at any one spot, if we put a converging lens with a large focal distance the beam would get more powerful as it gets closer to the focal distance and it would be just as powerful as it started at twice that distance. Right at the focal distance all 30W would be hitting a tiny spot on the balloon and it'll pop immediately.
- Get more space: 100 inflated balloons in a row take up quite a lot of room so make sure you have enough space to set it all up
- Don't have an audience: The guys floating around while we did it were very supportive and helped to inflate the balloons but you end up rushing something and not being quite so perfect about setting it all up. You can take multiple attempts but it's better to get it in one.