Flutterby™! : Boom, but no video 2008-11-17 04:48:05.394297+00

Boom, but no video

2008-11-17 04:48:05.394297+00 by Dan Lyke 7 comments

Forest wanted to blow something up. After last time, I was a little nervous about spooking the neighbors, so I thought "well, let's put it under water". So we filled a wastbasket with water, tied a 2 liter soda bottle to a couple of bricks, pumped it up to 150PSI, and took an 8 foot long strip of plywood with a screw driven through the end of it to pop the bottle.

When the water cleared, the wastebasket was destroyed, splayed open like a banana peel, the bottle, of course, was completely unrecognizable, and, after a few seconds, something clattered and tumbled on the top of the shed roof. We started taking stock of the destruction and realized that about a foot of the end of that plywood strip, complete with 3" screw driven through it, was what came tumbling down way over there.

Forest couldn't understand why I was reticent to blow anything else up this evening. Alas, the camera was in a weird mood, so, no video.

Owch, glad everyone's okay. You'll come up with a safer way to do that next time.

Safer?: A trashcan full of gasoline, a 2 liter bottle full of air (or O2) add an ignition source, and you could have an excellent aerosol bomb. I've seen them done with a half a gallon of gas and det cord, but this could make a really big boom. Of course, DHS and the BATF would not be so happy.

This really illustrates to me the power of air, which compresses, and water, which does not.

Makes me eye the two paintball tanks with 2000psi in them right now a little differently...

#Comment Re: made: 2008-11-17 18:11:07.745153+00 by: Dan Lyke [edit history]

Whump, yeah, we'll build our remote catastrophic failure inducer using a 2x4 to hold our screw next time. That should be less likely to shatter independently.

Meuon, the point of the water was to dampen the "explosion" sound, which it did. This made a dull thud, rather than the sharp crack of a straight air explosion, so I felt a lot less like I was wigging out the neighbors. But, yeah, now I have to be smarter about containers...

Skrubly, occasionally someone will propose an automobile that works off of compressed air. Having played with 150PSI, the idea of having reasonable automobile range quantity of 2k+PSI in an accident makes me have to change my undies.

#Comment Re: made: 2008-11-18 00:47:07.558866+00 by: mvandewettering

Back in the old days of my youth (all my stories are beginning this way lately), we did a similar experiment, but instead of high pressure and popping the bottle, we filled the plastic bottle about halfway full with dry ice, capped it and sank it in a big garbage can. Instant depth charges.

I'm actually really excited about the MDI compressed air car, but I would like to see documented video of crashes/pressure failures first.

The best personal illustration I have of the power of gases is while operating a CO2 fill station. I was filling a 20oz paintball CO2 tank as usual, when the hose fitting on the front of the station (which, stupidly, was facing towards me) decided not to be latched anymore. It blew off with a pop and struck me fairly hard in the chest. Nice it didn't hit me in the face.... but damn, it stung.

Always chain up your tanks; if they tip over for whatever reason and the tree on top breaks off, it would be entirely too exciting. Ignoring personal injury, I'm sure the property damage would be impressive.

MarkV, yeah, the neighborhood kids recently fired off a dry ice bomb, sans garbage can, that was really (really) loud, but I'm guessing there'll be less of that: a woman in Santa Rosa was injured when she attempted to pick up an unexploded dry ice bomb, initial news report here. I'm afraid that this'll have a chilling effect on adults safely exploring such things with their kids, which means that the kids will be doing things like setting one up, having it not go off, and then go "oh crap, scram" when someone shows up, resulting in... well... injuries like that.

So, speaking of which, did the shock destroy the can? I like having water to buffer the sound of the blast a bit, but I can't go through a wastebasket per explosion...

Skrubly, yeah, I'm becoming much better at wearing goggles and face shields in more situations, 'cause those injuries come from the things I've done a gazillion times and don't expect to go wrong.