Introduction: Building Prop Weapons From Junk

About: Untidy, disorganised and a bit silly. I am a photographer, artist, body artist, sculptor, prosthetic maker, model engineer, and general idiot who likes making stuff and messing about. I give hands on workshops…

I haven't written an Ible for a few years now mostly due to health issues. In the meantime they have slightly changed the format, so bear with me if I cock it all up!

I have been asked on a number of occasions to build 'game guns' for a few people. That is, build weapons that only exist as virtual weapons and try to make them into real tangible items for videos or photo shoots, part of some Cosplay or other costume parts.

In this Ible I will show the methods I used to make them from very cheap or junk materials. Mostly cardboard and foam. Once completed they are pretty sturdy and feel good in the hands, but obviously they won't stand up to heavy punishment or abuse. They should be easy to repair though.

Shown in the images are the Monte Carlo from the game Destiny, a Rail Gun prop, and an MA37 from the game Halo. I will describe how I built the MA37 in detail, the same techniques were used for all three weapons and should be adaptable to other designs as well.

All three of these weapons took in excess of 30 hours to build, so please don't ask me to make one for you, the idea is to try it for yourself.

Step 1: Reference Materials and Tools

You need to begin by obtaining as many reference images as you can find. Most game weapons are well covered on the internet. Try to find a decent set of orthographic projections (left side, right side, top, bottom, front and rear views). You will need at the very least a good technical drawing of the full length of one side along with it's dimensions.

You need to download and install 'Posterazer', a piece of software that will allow you to printout the drawing to full size on either A4 or Letter, and tape the sheets together to form a full sized plan. I use some thin card to print onto. I don't intend to explain the software to you, you will have to look it up and sort it out yourselves. Here's a link:


Tools you will require are:

A set of VERY sharp craft knives, Xacto, or a surgical scalpel, a box cutter, a snap off knife etc.

A pair of scissors

A few good steel rulers, a steel straight edge, some sharp pencils, or pens

A circle cutter and or a set of punches (a good paper punch or leather punches will do)

An engineers, or metal set square, possibly a protractor.

A small soldering iron with a pointed tip will help too

Step 2: Materials

Arm yourself with the following items:

Box cardboard (the corrugated type) I use old boxes from the local store which they give me. Get the biggest you can and cut them up into flat sheets using a box cutter.

Some sheets of card about 1.5 mm - 2 mm thick. In the UK I use 'layer pad' or mount board. I'm unsure of the US equivalent, but the stuff they use as framing card for watercolour paintings is about the right thickness and density. See what you can find.

Some cereal carton card (about 1 mm thick)

Some thin card (like birthday or greeting card thickness)

Some 'funky foam' or craft foam (EVA dense foam sheets). I use 1 mm and 2 mm thick foam

Possibly some pipe lagging foam or 'Pool Noodles' for round sections

Various bits of junk plastic pipe and odd plastic fittings - see what you can find.

Various glues. General purpose, some contact cement, cyanoacrylate (super glue), gorilla glue, etc

Spackle paste, Polyfilla or car body putty


Possibly a hot melt glue gun

Step 3: The Main Plans

Your first task is to produce the main set of full sized plans. Use the Posterazor software to do this.

Here I've printed out the 8 sheets of A4 on thin yellow card, trimmed them and taped them together.

I would make two or even three sets of these plans. That way you can cut them up to use as templates for the main card structures.

This set of plans were made by Budgie but the link has now died. I'm pretty sure you can still find a copy floating around on the net somewhere.

Step 4: Constructing the Core

Begin by cutting out the master template for one side. Here you can see the template for the Monte Carlo laid up onto the box card. You need to work out the guns thinnest section (usually about 1" across) and build the base core this thick. Cut out any holes where triggers, grip holds or similar are present. I've also removed the barrel, lights and other smaller or rounded items that will be added later. We just want the core sections.

Cut two sides as accurately and carefully as possible. In the second image you can see the two sides of the MA37 and the template I used above them.

Next cut a load of strips of box card 20 mm or 3/4" wide. these need to be accurately cut if it's going to work. Make sure that the corrugations run ACROSS the strips not down their length. This will give the structure it's strength.

Start by gluing the 20 mm strips around the outer edge of the core, for this I use a solvent free general purpose glue, but any general purpose glue that's not too runny will do.. Glue them to one side only and use your set square to ensure that they are perpendicular to the base side. For curving sections, use the corrugations to help you by cutting through the OUTER side of the outer layer of card. One corrugation in two or three. You will find that the box card then bends easily into shape.

Once all the outre edges are done, start to build up an internal 'lattice' of 20 mm strips in a random triangular pattern. Once it has all set, carefully glue the other side on making sure it all lines up well. I tend to put a couple of heavy books on top and leave it overnight to set.

Once completed you should have a very solid box core for your weapon as in the last image. It should be nice and sturdy and you can pick it up and check it for handling and general size and shape.

Step 5: Starting the Build Up

Next we need to begin to build up the body of the weapon. This is the reason that the core needs to be only the thickness of the thinnest section. In the first image you can see that I have used one of the master templates to mark out and cut the detail for the side panels of the barrel. I have used mount card for this. It requires two layers of card to create the slide patterns. These are then carefully glued on using GP glue and layered to form the detail.

In the second image you can see that I have added the lower slide sections from two identical pieces of mount card sandwiched together to get the correct thickness. These can only be determined by reference to the orginal game gun artwork and some guess work.

Next I very carefully cut out a piece of white card 1.5 mm thick and cut a hole in it to take a min-maglite torch in the front lower section. This was then glued into place with GP glue. I cut a length of round pipe lagging foam to form the front grip. Luckily for me this has a 15 mm or 1/2" hole running down it's length. Once glued into place and allowed to set, the maglite was simply a push fit through the front hole and is gripped by the pipe lagging. Result! The third image shows the maglite in place and switched on.

Depending on the weapon you choose to build, you will have to improvise with the materials and shapes you have available. I spend more time figuring out how to use what I have to make what I want than actually making it.

In the final image, I have added a barrel made from old bits of plastic pipe, a few hose fittings an some strips of paper and card glued on to match the original game artwork. I have also constructed two simple side boxes and a cover plate of 1.5 mm card for the front barrel nose. More of this in the next steps.

Step 6: Adding the Deeper Sections

For the deeper detail sections in the build up I use the same lattice structure design as we did on the core but using thinner card - 1.5 mm or even cereal carton will do it. Start by carefully taking measurements from the original template, transfer it to the card, and then carefully mark cut and measure as you go along.

In the first image I am working on the rear side pods. I have already assembled the lower section and I'm working on the raised part which sits at a different angle. You will have to work out the best way to construct these parts depending on your weapon of choice.

In the second image you can see the constructed lattice. In the third all the outer cladding has been added.

The last image shows the pod installed on the side of the gun.

You will also notice that I have added the first piece of funky foam to the nose pod of the barrel section. It's a lilac colour. More on that later.

Step 7: Ammo Counter Step One

Although the ammo counter won't actually count, I wanted it to be illuminated so I had to make a lens.

I carefully measured and cut two pieces of clear acetate, I think it came from a plastic food pack. Next I found a reasonable image of the counter on the net and manipulated in in Photoshop or Gimp to the correct size I needed. I then printed two copies off on a a colour inkjet printer using standard copy paper. I cut out the parts that were blue from only one of the pieces.

In the first image you can see all the elements prior to assembly. I then sandwiched them all together using clear general purpose glue and allowed them to dry. The final image shows the lens when back lit.

Step 8: Starting to Detail Out

Next I began to tackle some detailing. Refer to your artwork and master template and decide which parts are thicker and which are thinner, which need to be added in what order. I started with the magazine and hand grip detail.

In the first image I have started to add depth to the grip and magazine using the master template to transfer the sections to card of various thicknesses and built them up using GP glue. I've added two small bits of funky foam (the lilac colour) and drawn on some of the etch detail with a pen. The second image shows this in more detail. I've also added a small lilac piece of funky foam to the rear upper edge of the back of the gun. The foam needs to be measured and glued on using contact cement or it will try to peel off.

Certain compound curves or smoothed details are simply too difficult to replicate in card or foam. In the third image I have added spackle paste (Polyfilla) to the areas of the grip that need to be smoothed out. I've also added some small funky foam detail and again drawn the etch marks on with a pen.

In the forth image I have started to really add the funky foam. It's advantages are that it subtly rounds off those angular edges and is much nicer to the touch. The colours don't matter since we are going to paint over it all. The grip spackle paste has been sanded smooth.

You will also notice that the side of the grip has some engraved detail added to the funky foam (the pink bit). This is done using a soldering iron with a pointed tip. Light pressure on the foam with the iron will leave a nice crisp line engraved on the foam surface.

In the final image I have added a lot more foam, including small round details cut with the leather punch and more engraving on the forward grip section.

The funky foam cuts beautifully if you use a very sharp scalpel and punches.

Step 9: The Upper Barrel Boxes

Next I tackled the upper barrel boxes. Our original ammo counter lens was given a card bezel and the box constructed exactly the same way as the other units. The only exception being the addition of an internal super bright LED and the leads being run out of the back for the battery box. The first two images show the ammo box illuminated but before the addition of the funky foam coating.

The third image shows the front sight box. This is simply a similar construction to all the others. The sighting barrel is on old garden hose connector. It has been clad in funky foam and glued in place using GP glue.

The forth image is the battery box. I've added a simple switch for the LED and the battery holder simply fits inside it. This box needs to be a push fit onto the upper barrel since it needs to be removable to change out the batteries. I was careful when constructing this box to ensure it was a good tight fit to the upper rail of the barrel.

In the fifth image you can see all three boxes fitted to the upper barrel. The sight box and the ammo counter box are glued on, the battery box in the middle is a push on fit.

Step 10: Shoulder Stop

The shoulder stop is a laminate. Three layers of 2 mm card, and two layers of 12 mm EVA play mat were laminated using contact cement. Then the entire block was sanded to shape. The first image shows the laminated blocks.

In the second image the block has been sanded to shape and a section of funky foam added for the detail.

In the third image an old off cut of plastic pipe has been glued into place using the hot melt glue gun.

Step 11: Completing Construction

Some very minor details were added using funky foam and the punch set.

Here are 4 images of the completed construction phase.

Step 12: Painting Stage One

Normally I would have given the gun a coat of grey car body primer, but I didn't have any left. The ammo lens was masked off and then the entire gun was given three coats of matt black car body paint using spray cans.

Step 13: Weathering and Patina

The first three images show some airbrushing with ever lighter greay tones to weather the main panels.

The third and fourth images show some 'metalising' using the dry brush technique and some gunmetal and silver colours.

The fith image shows some subtle shadow additions. The final three images show the addition of tactical markings and some browns and blacks.

Step 14: Completion

The completed weapon.

If this was of interest I might put up some converted Nerf weapons and some Steampunk guns.