Introduction: Double-Barrel Shotfun
The Double-Barrel Shotfun - dealing out enjoyment at the pull of a trigger!
It's just what you needed - an overly-complex method of firing off two party-poppers at once.
(You can now accessorise your Shotfun with a dedicated bandolier!)
Step 1: Materials and Tools
You can modify this project to your needs, but this is what I used:
- 4mm plywood sheet
- Offcut of 6mm plywood
- 32mm waste pipe
- Industrial adhesive
- Masking tape
- 6mm dowel
- Scrap corrugated card
- Lasercutter
- Scrollsaw
- Teaspoon
- Files
- Sander
- Rubber mallet
Step 2: Prototyping
This quick lash-up proved that a steady pull via a lever would work to fire a party popper.
Step 3: Lock, Stock...
Once the concept was proven, I needed to stream-line it. I drew the laser cutting files in LaserCAM 2D, purely because it's the software my school bought with the laser cutter. You can reproduce your own version in whatever software you prefer.
I designed most of it to be out of 4mm ply, but I decided that the section that would brace the poppers (the part that looks a liitle bit like a heart, and a little like a Batman logo) needed to be stronger, so I cut that out of 6mm plywood.
I took a screenshot of the design that you can use - the odd layout is to fit the piece of plywood I had close to hand.
The MCM file itself is in the zip folder with this step. It's not huge, it just isn't recognised by the uploader if you leave it as an MCM.
Attachments
Step 4: Testing & Cutting
To check the parts fit together, and fit my hand, I ran off a set of pieces in corrugated cardboard.
The parts all fit perfectly, but I discovered a bug in the software; the curves of the bracing piece were only rastered (etched), not cut by the laser cutter. I ended up using the rastered cardboard test-piece as a template for the bracing piece, which I cut out roughly with my scrollsaw, then filed and sanded it to shape.
Step 5: Construction
See the photos for laying the parts out.
I used short pieces of 6mm dowel to brace the parts. The fit in the laser-cut holes was snug, so I used a small rubber mallet to get them in place, protecting the gun with a scrap of timber. Wood-glue between the layers ensures a permanent fix.
Beware!
Watch which way round you fit the lever - the slot needs to face backwards - and be careful not to glue it in place. It's not obvious from the images, but the hole I cut in the lever is half a millimetre wider than the other holes, so that the lever will move freely, not stiffly.
I sanded the dowels flush with the plywood, and cleaned off the cutting soot with a few strokes of the same sandpaper.
Once the rest of the woodwork was glued, I glued and friction-fitted the bracing piece in place.
Step 6: Making Barrels
I cut two pieces of waste-pipe for the barrels, each just over 40cm long.
The waste pipe I used was sold as "32mm diameter", which turned out to be the internal diameter. This was the closest fit I could get to the 26mm outer diameter of the party poppers.
I could have bought 28mm copper tube, but it cost far, far more than the plastic waste pipe, and I'm not convinced that party poppers come in a standard diameter, so there's wiggle-room to fit larger poppers.
To be able to load the gun, I needed a notch out of the barrels. I measured it by eye, then cut it with the scroll-saw. The curved slot gives enough space to push the popper into the barrel, and then drop the stalk of the popper into the notch of the bracing piece.
See the photos for the size of the notch compared to the poppers.
Step 7: Fit Barrels.
With a spare set of hands (thank you, Kitewife!), I fitted the barrels in place with masking tape, and then filled in the gap between the plywood and the barrel with Sugru.
To do the full length of the barrel took two sachets of black Sugru. I rolled the Sugru into "worms", then used the end of a teaspoon to push the worms into the gap under the barrels, and to smooth off the surface. See the Sugru packs and website for correct handling procedures.
Disaster!
The Sugru failed! It may have been a lack of contact area, or the age of the packs (rather close to their expiry date), but it didn't survive some basic handling, do I cleaned off the Sugru, and tried again with an interesting mastic-style industrial adhesive called Sticks like sh*t (seriously, check the photos! ).
Step 8: Finishing
Here, I reached a dilemma...
My original intention was to paint the barrels matt-black, and use a dark varnish on the stock (to make the shotfun look more like a shotgun), but now, as I've been playing with it, the plastic-and-ply colour scheme has grown on me. I like it, and, for now, I'm going to leave it.
Step 9: Modified Ammunition
Party poppers are very simple to modify, as long as you take a little care:
- Use a thin blade or long fingernail to prise out the cardboard disc, doing as little damage as possible.
- I remove the existing streamers, but you can leave them in if you want.
- Do not remove the second disc - I tried it, to fit in more flour, but the popper's explosive needs space to expand. If you pack things around the popping bit, nothing gets fired out.
- About half a teaspoon of flour fits in nicely. Don't pack it tightly, or it won't come out.
- Slide the original card disc back into place, between the plastic corrugations - sliding a thumbnail around the edge works well.
Step 10: Loading and Using
To load, push the popper in through the notch, and lay the string through the slot in the lever. You can load both barrels, and put both strings in the slot at the same time.
Pull the lever, and... !

Runner Up in the
Epilog Challenge V

Participated in the
Halloween Props Contest
121 Comments
9 years ago on Introduction
I used your idea as a base, cut out the shapes from plywood using a jigsaw and it works. I can report though that knotting the string together and looping them over the trigger only fires one shot, the second one does nothing once the string's out. Works for firing the poppers and actually aims the streamers. :)
Reply 9 years ago on Introduction
Maybe, if you knot closer to the popper?
It would be cool if you could post a photo of your version, or even a video?
Reply 9 years ago on Introduction
Can't get the knot any closer, so cut a slot in the top of the trigger as with your design, works fine. I'm tempted to cut an actual trigger design into it, just for the look of it. :)
The angle's a bit odd on the photos as I had to fit it all in frame at arms length.
4 years ago
If you put airsoft bbs in the party poppers instead of streamers you could turn it into a real shot gun.
Reply 4 years ago
Try it, let me know how it works out?
10 years ago on Introduction
What do they use for a charge?
Reply 10 years ago on Introduction
The party poppers? It's a small cylinder on the end of the string - when you pull the string out, friction between what's on the string and the lining of the cylinder trigger the explosion. It's very like a match, but faster.
Reply 10 years ago on Introduction
so is it a form of gun powder?? Hm,mmmm how could ya get a bigger bang out of it ?? Ya got me thinking kiteman lol
Reply 10 years ago on Introduction
Packing the stem with gunpowder, instead of flower?
Be careful of the back-blast.
Reply 6 years ago
so i will put the flower out ,put gunpowder in about 1/3 of the container
and after that i will put a lot of small piece of projectile like wood or small metal
and that's what you call shot fun
Reply 6 years ago
In all honesty, that would be what you call a couple of lost fingers, maybe an eye.
Reply 6 years ago
can i make it abit dangerous plz?
Reply 6 years ago
Haha, it's up to you, they're your fingers!
Reply 5 years ago
my finger will be like oof
Reply 8 years ago
even a small quantity results in total disintegration. was very glad I'd extended the pull stringt and was 20m away
Reply 8 years ago on Introduction
Gosh - do you have images of the result?
Reply 8 years ago on Introduction
was many years ago before digital cameras were so wide spread so I'm afraid not
Reply 10 years ago on Introduction
Hmmm. How about a. Shotgun primer or a rifle shell primer?
Reply 10 years ago on Introduction
They're your fingers...
Reply 10 years ago on Introduction
or eyes.....