The Halitosis Howitzer

[mklotz]

If you want to get people's (especially younger people) attention at your next engine show or backyard barbecue, you just can't beat a small explosion. I've learned that the nanny-state frowns on 1" smoothbore, black powder cannons firing ball bearings through tree trunks so I built a safe cannon (actually a howitzer) that doesn't sacrifice that head-raising CRACK needed to get yourself noticed.

The top from a soft plastic 35mm film canister is screwed to a block of wood. The piezoelectric sparking element is cannabalized from a commercial butane barbecue lighter and its two wires led through holes in the block to emerge into the cannister top (see detail in second photo. Arrange the wires so, when the piezo button is pressed, you get a nice juicy spark across the wires.

Fuel is provided from a pocket-sized cannister of aerosol breathspray. Spray a bit into the film cannister, immediately mount the cannister on its top on the howitzer, press the piezo button and the cannister will fly twenty to thirty feet with a very satisfying BANG!
The plastic film cannister won't do any damage if it hits something and, with the small amount of propellant, this is actually a pretty safe device.

Aerosol breathspray works well. It contains alcohol and the propellant is butane so it's fairly easy to get a proper mix of propellant and air in the cannister. Non-pressurized breathspray works too but you'll need to experiment a bit to get the right air-fuel mixture. Hairspray works well but leaves a sticky residue. Experiment - but resist the urge to try acetlyene.

If you have younger kids, ensure that they understand that this is Daddy's toy and lock it securely away when not in use.

Oh, one more thing. When testing the piezo element, don't touch the wires. DAMHIKT.

[ncollar]

Marv
Tooo Coool

[rlm98253]

One question, mklotz. Where, in this digital age, do you find empty 35mm film canisters?

[Toolmaker51]

One question, mklotz. Where, in this digital age, do you find empty 35mm film canisters?

Cause he didn't toss them in the first place. DAMHIKT.
I'm privy to a world class selection of like-sized Rx containers. Snap cap versions might triple the chamber volume available in a 35mm canister...hmmm

[mklotz]

One question, mklotz. Where, in this digital age, do you find empty 35mm film canisters?

I have a good deal of trouble discarding any nicely configured small container. In addition, I've worked out several quick ways to defeat those infuriating child-proof caps on containers.

There's nothing sacred about film cannisters. Any small pop-top container will work. About the only consideration is the fact that it shouldn't be hard enough or massive enough to inflict damage or knock valuable antique vases off the mantle.

If you're really safety conscious you can attach a string between the howitzer base and projectile and make it into a "pop + howitzer" = "powitzer".

[Paul Alciatore]

Boy, that was a real easy Google:

https://www.bing.com/search?q=35mm+f...ZI&form=MOZLBR

Apparently Marv is not the only one who likes to use them. Personally I prefer recycling the plastic pill bottles. Some pharmacies can supply them with the same style of snap cap as the plastic film containers have but you have to request "not child safe". They are transparent enough so you can see the contents. I have actually reorganized my screw and bolt collection with them. Various sized pill bottles hold all my screws from 4-40 up to 12-24. I have them in cardboard bins, one bin for each screw size. Metric too.

One question, mklotz. Where, in this digital age, do you find empty 35mm film canisters?

[MegaGash]

Hugely Entertaining.
I once saw a quote somewhere that said: "Growing OLD is INEVITABLE; growing UP is OPTIONAL"
Just about covers it, methinks?
PS: this is meant as a compliment......

[ncollar]

MegaGash
It is taken as a complement, I like having options.
Nelson

[NeiljohnUK]

One question, mklotz. Where, in this digital age, do you find empty 35mm film canisters?

From one of us who still shoots 35mm! Yes mainly digital, but the F2 still gets exercised when I'm in the mood. Film canisters are handy for lots of things, small stuff especially, and stopping loose change wearing holes in pockets. Also fit well in speed-loader pouches with 1/4" foam liners to keep weight on the belt and out of pockets.

[garage nut]

Makes me think back about 30 years, we made potato guns like this. Used 40 or 50mm PVC tube and glued on a screw on end cap. Then the same configuration with the wires in the cap. Find a potato that fits loosely in the tube and throw it in from the front, 3 x self tappers about 3" from the cap ensures the potatoes does not upset your firing wires. We used pressurized deodorant as a propellant. Well you can figure it out from here. Not a toy for kids. The potatoes can be shot some 50m depending on the length of the tube and the fit potato to tube you have. Like I say no toy for a kid., but mechanical engineering students can have a lot of fun.

Thanks for taking me back memory lane.

Had to edit the post and change 20 to 30....man time is flying.