Balloon pop laser

[Rachie]

Hello, I'm looking for a laser well suited to popping balloons. I'm in charge of planning a large set of science demonstrations for 1000+ students, and I think popping a bunch of balloons would be a nice project.

It's a large outdoor area, so I was thinking it would be even more fun to use balloons filled with hydrogen or methane.

What wavelengths and Wattages would be best for this? Can anyone recommend a good laser to buy? I'd like something with a tripod mount, and I'll keep everyone far away from it. Should I get a pair of laser goggles too?

Thanks!

 

[PhotonWrangler]

Because this is a "public performance," FDA rules kick in regarding lasers greater than 5 milliwatts, and they would be likely to deny a permit for this use. You would be better served by attaching squibs to the balloons and firing them from a remote control panel. This will be much safer and just as dramatic. Be safe.

 

[Rachie]

Getting a permit is actually doable in this case. The school has insurance, and I don't see how this would be considered any different than a typical laser show. We were considering using conventional (low powered) scanning lasers as well. How does one go through the appropriate channels to do this?

Squibs will be a backup in case we end up not using a laser.

 

[PhotonWrangler]

Here are a couple of good starting points -

ILDA guide on laser show safety -
http://www.laserist.org/safety-basics.htm

FDA guide on laser shows -
http://www.fda.gov/downloads/AboutFDA/ReportsManualsForms/Forms/UCM081634.pdf

After reading the FDA document, you'll probably want to go with the squibs.

 

[Rachie]

It still looks doable. I don't think we'll have any trouble submitting an FDA report, and getting FAA clearance.

So, any advice on what laser to buy?

 

[PhotonWrangler]

There are additional challenges here.

1) Balloons are shiny. A portion of the energy hitting the balloon will be reflected and scattered among bystanders. I don't see this as being easily controllable.

2) Because this is outdoors, the balloons will be moving in the breeze. This means the targeted area will be shifting around, requiring more heat than a handheld "pointer" laser can deliver to pop them. There's also the direct cooling effect of the wind itself that needs to be overcome. We're talking argon laser territory now.

3) Because the heating will be uneven due to breezes, you can't guarantee that the balloons will pop exactly on cue.

Squibs can solve all of these problems and will produce the intended results exactly on cue every time. And they will be safer and way, way cheaper. In my opinion, what matters is the result, not what you use to produce it.

 

[Rachie]

#2 and 3 shouldn't be too difficult to overcome. Timing isn't important, so taking several seconds to pop a balloon is perfectly fine, and a few initiator balloons can be securely tethered. #1 is tricky. I can't think of a good solution, short of painting them matte black.

How about simply having a laser as an artificial star? There will be no reflection issues at all, and it will still look impressive.

 

[candlelights]

Safety Protector should be well prepared. Especilly for the students. Good luck.

 

[Rachie]

I'm envisioning the laser staked into the ground, well overhead, pointed straight up. There will be a radius of caution tape around it, with teachers standing guard. A few trusted people will be inside, each having their own power cutoff switch. The laser will be stored in a locked box before and after use. That should cover any safety issues related to student interference.

If that isn't enough, I'll mount it on the roof of the building.

 

[PhotonWrangler]

#2 and 3 shouldn't be too difficult to overcome. Timing isn't important, so taking several seconds to pop a balloon is perfectly fine, and a few initiator balloons can be securely tethered. #1 is tricky. I can't think of a good solution, short of painting them matte black.

How about simply having a laser as an artificial star? There will be no reflection issues at all, and it will still look impressive.

Do you mean as a star that shines on a fixed target? That would seem reasonable and would provide a safe beam stop. On the other hand if you're going to point it straight up, there's the issue of aircraft.

If I was doing this, I would go for a conventional laser show unit with lots of fog, and some preprogrammed moves in the laser projector that would point at the balloons. Then I'd trigger the balloons to pop via squibs when the laser hit them. This gets around the problems associated with very high powered lasers and still produces the same visual result.

 

[Rachie]

So, once again, can anyone suggest a laser?

 

[FreedomHolland]

If i was you i will not do this to a big public of you hit some one and he or she gets eye damage you sir got a problem. Not to be rude. But if you dont wear glasses or take the correct safety handelings you will get hurt one day. I know where i`m talking about. I cut my hand withe a big laser at my work i can tell you its not fun. If i was you i will record it and show it then to the people. Or if you can get it use Arc welding shield !

Those are often red plastic sheet. those will block UV and all High wavelength lights. This is what we use on our work. You can look through it. but will take a big amount off ''damage'' out the laser if it will scatter.

 

[Remington597]

It's a lawsuit waiting to happen and it's not a "typical laser show" because you want a very high power burning laser. I don't think the FAA will give you clearance to point such a laser in the sky just so you can pop balloons. Plus where are you going to buy such a high power laser from? A 1.5w laser isn't going to do it.

 

[Norm]

Due to the public performance factor involving risk to public safety this thread is closed. - Norm