Steampunk Gatling Gun Arm




About: I'll cut and paste stuff here as time goes on.

I often get excited about Halloween. Nothing is cooler than dressing up in your favorite outlandish style (creepy or not) and collecting a bag full of free candy!
This Halloween, the coolest ideas for costumes are anything Steampunk. And if that Steampunk costume has this gun as part of it, your coolness level will be boosted by +4, Lightning Element.
The following is my journey through crafting this beast.


Step 1: Materials and Tools

For this project, you will need a host of materials. One of the main parts about Steampunk I like best is its versatility. “Junk” becomes “structure and design,” and “Victorian” becomes “GQ.” Now go, and gather:

 - PVC pipe – some your arm can fit into (around two feet long), and then some you can comfortably grasp (around 12 feet of it).
 - Spray paint -- lack, gold, and silver. Copper would work as well.
 - Spray paint drop-cloth or guard (to avoid tagging your driveway with the outline of your pieces)
 - Junk, A.K.A. Vital Functional Parts.
 - A Hose, preferably with ribbing for effect
 - A spare gauge
 - Momentary switch
 - Wire, paired, approximately 6 feet (12 feet total wire if single-stranded)
 - 3 AA Batteries and 3x-battery holder
 - Several LEDs (as many as you will have barrels in the gun. I had 16).

 - Hacksaw, bandsaw, or your preferred PVC-cutting tool (I used an angle grinder, which is quite ill-advised).
 - Super glue, putty epoxy, or even silicon caulk (which is what I had readily available)
 - Hot glue and gun
 - Drill and many assorted bits, hopefully with one close to the same diameter as the thinner PVC
 - Rotary file, in case you don't have the huge drill bit
 - Measuring tape
 - Solder and soldering iron

If you want to skip the electronics part, it will make this piece much more simple. You can omit the switch, wire, batteries and holder, LEDs, and the solder.

Step 2: Measure and Cut Structure

Measure the outer diameter of the larger PVC pipe. Cut the smaller PVC pipe (hereafter called the “handle”) to that length. My pipe OD was 4.25", so the handle was cut at 4.25".
Grab the smaller PVC pipe in your gun hand. Measure the distance from the crook of your elbow (or where the butt of the gun will be comfortable) to the center of the grip (see picture). This gives the distance down the larger pipe where you will want to cut it off. Sand down the edges that will make contact with your skin so that you don’t cut yourself when using it.

Step 3: The Handle

Drill a pilot hole in the six-inch mark on the arm-pipe. Then widen the hole with either a drill bit as wide as your handle, or with a rotary file. Check to make sure it fits snugly.

Now then. The electronics in this are optional. On one hand, they look really awesome. A laser sight? LEDs making the barrels glow? Heck yeah! On the other hand, the electronics made the project about ten times as complicated. If you want to omit the electronics, skip to the next step.

If you are going all out, make a mark on the handle where the tip of your trigger finger is. Drill a hole on that mark big enough to fit your switch into. It’ll probably be on the side, rather than straight forward, unless you plan to make your gun ambidextrous. Straight forward is just fine.
Slide the handle into the larger pipe in the hole you drilled earlier. Glue it in place with super glue or epoxy and let set. Be sure to keep the holes and airways open for wiring.

Wire your switch with long leads and feed them into the trigger hole. Use epoxy or hot glue to hold the trigger in the hole at your preferred trigger position. The wire should be sticking out the top of the handle, through the arm-pipe hole.

Step 4: The Barrels: Measuring and Cutting

I painted the arm-pipe before worrying about the barrels, but in hindsight it would have been easier to work with if I'd painted it all at once. Hence, this step comes before the paint part.
Measure from the center of the arm-pipe to the end, and add an inch. This will be the length of your barrels. These ones turned out to be about 8.25 inches.
Cut about 16 pieces (if that is how many barrels you want) to this length and sand them down as accurately as you can. With an angle grinder, I didn't do as well as I wanted, but it isn't that noticeable.

Step 5: Paint and Glue

Take your spray paint and paint the arm-pipe, the barrels, the battery holder, and any bits of junk that don't already look metallic. A good technique for giving a brass look is to spray an object black, then again with gold paint. The effect is impressive in person. Consult your paint can for estimated drying time.

I've found that on some of the smoother parts like the barrels, it was necessary to rub the surface down with some fine sandpaper in order to get the paint to stick and hold still while drying. PVC wasn't really made to be the ideal paint surface. Rub in a horizontal direction and stand the tube on an end so that the paint sits in the scratches instead of running down.

When everything is dry, glue the barrels onto the gun in an evenly-spaced manner. I think a good technique for this is to glue them on opposite ends, each pole at a time. This way you can estimate more easily half-distances along the circumference of the arm-pipe (which is why the number 16 worked well for me). Allow a small gap in between each barrel. Too many barrels, and you won't be able to fit them all on the gun! Make sure they are even, at least on the front end of the gun, and hanging over about an inch. The effect will be ruined if they aren't even! If the barrels aren't all the exact same length (as mine were not), the back ends can be a bit uneven, as people mostly look at the front end.

Step 6: The Electronics

If you are omitting the electronics in this project, skip to the next step.

Take all your LEDs and test them for polarity. Solder a black-wire lead to the negative terminals, and a plain lead to the positive terminals. Or whatever helps you remember their polarity. The leads should be about four inches long.

I hot-glued the lead joints to make them sturdy.

Next, hot glue the LEDs to the inside of their corresponding barrels, to help them stay in place and point down the barrel.
Then wrap two separate rings of copper around the arm-pipe near the LEDs. It helps to have a perfectly circular cut of copper wire, slightly smaller than the arm-pipe. This way, they will "hug" the pipe and not move very much. Call one ring the "positive node" and the other "negative node."
In hindsight, braided copper strands of the same gauge would have worked much better, to make the soldering easier and the connections in the solder joints would remain more stable.
As it is, I wrapped each LED lead around its corresponding node and back onto itself, tightly, and soldered it that way. It works, mostly. :-)

I positioned the laser in the top barrel (the one under which the trigger leads come out of the handle). Interesting that it takes the same voltage as these LEDs, no?

Step 7:

I used hot glue to attach the front plate. It happened to be very close to the same diameter as the arm-pipe, so with a thick bead of hot glue, it stuck very securely. Again, your favorite or most available bonding substance is perfect.

Take the hose and wrap it around the gun. I pointed one nozzle at the laser, to make it look like it was feeding the bullets through that way. The other nozzle didn't quite bend into the battery box as I wanted it to, so it received a gauge instead.

The hose was really finicky for me, and I kept having to adjust it. It started scratching the paint off. Try to get it right on your first try! Apply glue discreetly to areas of potential trouble with this.

Step 8: Play!

Now test it to make sure it works. Put in the batteries, hit the trigger switch, and maybe even turn out the lights to see the LED lights better. You should probably also wear other steampunk things while doing this test. Speaking of which, I've made a slideshow out of those goggles.



    • Woodworking Contest

      Woodworking Contest
    • Gardening Contest

      Gardening Contest
    • Classroom Science Contest

      Classroom Science Contest

    64 Discussions


    1 year ago

    This is p cool. Think I mit make this but add a simple motor system so it spins


    4 years ago

    thanks man, turned out great for my next comic con costume


    5 years ago

    What kind of jacket was that, I've been looking into a steampunk explorer costume and that jacket would be perfect.


    9 years ago on Step 8

     If the light on the indicator is too bright you could always place a piece of transparent plastic over it to diffuse the light?

    3 replies

    Reply 7 years ago on Introduction

    Or what you can do if thats the case, You can stick a resistor before the light. its easier to do that than to place a piece of plastic over the liht which could possibly melt and ruin this fantastic piece.


    Reply 7 years ago on Step 8

    Yes, diffused light in general looks better than hot point for steampunk themes. Gives the light a warmth similar to light produced by incandescent bulbs


    Reply 9 years ago on Step 8

    Yes, cellophane probably would have come in handy.


    7 years ago on Introduction

    FRIKIN AWESOME!!! I am using this for Halloween(plus a few modifications)


    8 years ago on Step 7

    why not add lasers instead of led's in the tubes then cut the thing in half just before it reach;s the tubes, put the tube half on a plate with a hole then do the same to the other except adding a motor or something that can fit in ther with a usable power source externally somewhere with a button leading on the inside u can use to make it rotate, ofcourse keeping in mind to find a way to avoid the wires from twisting around the body work, maybe a wireless connection that tells the led's to turn on when u push a button or something

    1 reply

    8 years ago on Introduction

    I started on something quite similar to this a few months before Halloween. The main body was a trash bin, and it span with an electric screwdriver. In the end, the barrels wouldn't stay on the circular plate that was supposed to spin. After that stopped working, I tried to turn it into a spinning boring drill bit. That also didn't work. It was so close, though.

    7 replies

    Reply 8 years ago on Introduction

    I find that, sometimes, hitting a dead end with ideas isn't actually the end if I set it aside for a little while. Eventually I can come back to it with a fresh brain and new ideas come to me. Even just picking up what you've got and looking at it from different angles can really give you the new perspective you need for that.


    Reply 8 years ago on Introduction

    Yeah, It's still lying around in my workshop. Maybe I'll bring it back for next year.


    Reply 8 years ago on Introduction

    Post an Instructable in progress! With pictures! (I can't say that enough!)


    Reply 8 years ago on Introduction

    how did you attach your barrels? indy mogul did something almost exactly like you tried, but they glued wooden dowels into the barrels (the end that attaches to the circle thing...) a couple of wood screws and they should stay.... though, i suggest a second circle thing that your barrels will pass through for extra stability.


    Reply 8 years ago on Introduction

    Mine was a plastic film canister top with spraypaint caps glued to it. The idea was that the tubes would slide into the caps, but the caps couldn't take the weight. Indy Mogul (my main inspiration for this project) cut holes with a hole saw, but I didn't have one and didn't want to buy one. I did have a crudely cut cardboard support, but in the end, the weight and centrifugal force broke the caps off. If I pick this project back up again, I'll consider using the dowel method that you suggest. Thanks, Noahh


    Reply 8 years ago on Introduction

    you know, a hole saw aint that expensive..... especally if your just buying one...

    good luck, hope you can finish yours. i have a similar project, the only difference being it is concealable. unfortunately, its still in the planning stage.

    here's a link to the forum post i made asking for ideas.