Space Laser Rifle Prop

Is it possible to build a laser rifle prop out of cardboard that would be good enough for the movie industry? If you take your time and accurately cut and assemble the pieces, the answer is possibly yes (maybe not for extreme close ups though, after all, this is made from cardboard). If you want to take the easy way you could use a laser cutter. However, using hand tools only, you will demonstrate your skills as a builder! This project was designed on Coreldraw but you could easily hand draw your design. Cutting out the pieces accurately is the most important part of the entire project. I used a scroll saw and various razor knives and X-acto blades. A drill press using forstner bits makes fairly clean holes in cardboard. However, this project could be accomplished with a razor knife alone if you don't have access to power tools. Just take your time and be accurate.

Supplies

3 to 4 different thicknesses of cardboard

Razor knife

Forstner drill bits

Carpenters wood glue

Spray paint

Assorted button cap machine screws

Optional: scroll saw, drill press, vise

Lay Out Your Design

These parts were designed and printed from Coreldraw but sketching directly onto the cardboard will work equally well.

Tape Down Main Rifle Body

Tape down the main rifle body on 1/2 inch thick cardboard. If you can't find 1/2 inch, laminate several layers to achieve this thickness. A thick core will ensure a rigid substructure.

Drilling Radius Curves

Using a forstner drill bit will cut clean holes for all Inside curves. A sharp bit is essential. As you drill, the cardboard will delaminate and you will have to clean the bit several times per hole.

Cutting Out the Main Body

Now that all holes are drilled, proceed to cutting out the body. Using a scroll saw is probably the easiest but a razor knife with a new blade will work (it just takes more time).

Burnishing the Edges

Burnishing the edges with glue is essential for adding strength. Also, the glue softens the cardboard to help smooth out any imperfections. Plus the glue will start to fill in the porous nature of cardboard. Apply glue generously and work in with your finger. After 1 hour, burnish with a smooth metal rod or dowel. After another hour apply more glue and burnish again.

Completing the Main Body

The main body is now complete. All edges have been reinforced with glue and burnished. Make sure all imperfections have been smoothed and all lines look clean.

Cutting Out Top Pieces

Now tape down the next group of parts from your design. These parts were cut from 3/8 inch cardboard. Use the same process of drilling all applicable holes and cut out all parts.

More Burnishing

Use the same process of gluing the edges and burnishing. It might not look good at first but eventually it will start to resemble something other than cardboard.

Top Sections

Here are some of the top sections ready for burnishing and refinement. Here is where you need to pay attention to the smallest detail before painting.

Painting the Parts

Here some of the parts are edged, burnished and primed. These will be added later and primed again. Then a contrasting top coat will help these parts highlight the may body.

Using Fasteners on Cardboard

Cardboard has no inherent strength when using threaded fasteners. This is a must have tip when building with cardboard. First drill a hole smaller than the diameter of your fastener. Then saturate the hole with standard superglue. Insert the narrow applicator tip deep into the hole so the superglue can get evenly dispersed. Allow the superglue to fully cure for several hours. Now you can screw in your fastener without the cardboard stripping out. I always go one step further and use a tap to cut the proper threads. You will be amazed at the new holding power of the cardboard.

Making the Trigger

Here the trigger is getting the first application of glue. Parts never look very good at first. After 4 applications of glue and sanding, the trigger is sprayed with primer. Test fitting in the finger hole shows the narrow slot that accepts the spring.

Pistol Grips

I used 1/2 inch cardboard for the grips. After the pistol grips are cut out, place each one between 2 pieces of wood and compress in a vise until the thickness is reduced by 1/3. Then proceed to edge treatment. You can start with thinner cardboard if desired but by compressing thicker cardboard, the grips are denser and stronger.

Main Body Top Plates

Here is one of the top section plates. There is one for each side, both identical. The same process is involved for these, drilling with forstner bits, cutting out, edge gluing, burnishing, etc.

Assembly and Painting

Glue all top sections down and spray with primer and top coat. I chose a textured neutral color that attempts to mimic the look of metal and/or a composite type of gun material. The end goal is to hide the fact that this is made from cardboard. Here you can see the first top coat of textured paint. You can still see some of the primer here and there. Don't try to spray everything at once. Avoid paint runs and drips. The finished body has 3 coats of textured paint.
Insert the trigger and spring into the finger housing and screw one 8/32 by 3/4 inch button head cap screws through the main body (these holes have already been drilled) and into the trigger. One screw from each side and the trigger is secured. Check for smooth action and adjust if necessary.

Embellishing and Fine Tuning

Cut a 3.5 inch section of heavy 1/2 diameter cardboard tubing. Round each end and strengthen with glue. Allow to dry and then spray paint. This piece fits into the slot behind the front emitter. A 5/8 inch diameter cardboard tube is fitted into the end of the barrel section. Drill a 5/8 inch hole and glue in place.
This tube was used to hold an old drill bit. A keypad was designed and printed on heavy archival matte paper and then glued onto 1/8 inch rigid cardboard (non corrugated) . There are 2 cutouts that accept cylindrical tanks. These were made on a lathe from an old tool handle. Drill a 5/16 inch hole in one end for a cable of your choice. Prime and paint.

Front Radiator Fins

Radiator fins are optional but add a nice look. Cut out 4 pairs of fins from clear hard pine. Sand each end to a 1/4 inch radius and fit till snug. Lightly sand the edges and then paint and install. If you really want to show off your builder skills, round over all exposed edges to a 1/4 inch radius. These fins are small and have to filed and sanded by hand. It's a more refined look and worth the time to round over.

Replacing Front Emitter Tube

The front cardboard emitter tube didn't look good to me so I machined a brass one. If you don't have access to a metal lathe, the original cardboard tube will suffice. Or you could attach almost anything that strikes your fancy. Try to keep it simple though.

A Finished Laser Rifle

This is not a quick project and will take some time to build properly. But the end result is something that can be displayed on a wall, used for cosplay or maybe even a prop in a movie. You can continue to add embellishments if desired but this laser rifle is basically finished. And having a spring loaded trigger adds a little realism when you want to play with it. There is always room for improvement and I'm sure over the next few weeks I'll spend a few more hours in refinement mode.