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Build Your Own Marshmallow Cannon

By Joe Hudy

Assembly Time: 5-8 Hours
Skill Level: Intermediate

Completed CannonCompleted Cannon
MarshmallowsDon't forget the marshmallows!

Step 1: Prepping the Parts for Your Cannon

Prepping the PartsPVC Corners and Ts

Before you get started, make sure you have all the parts you need. Cut pieces are not pictured. You will need to cut them yourself. PVC glue needs to be twisted while fitting together. It makes a better seal. However, there are a few spots where twisting can't be done.

Click here for the complete parts list featured on Make Projects.

Step 2: Cutting the PVC

Cutting the PVC
Cut all the pieces of pipe to the dimensions below:

  • 4 - 1 1/2" x 2 1/4"
  • 1 - 1 1/2" x 6 1/2"
  • 1 - 1 1/2" x 10"
  • 1 - 1 1/2" x 3 7/8"
  • 1 - 1" x 2 1/2"
  • 1 - 1" x 2"
  • 3 - 3/4" x 1 1/2"

  • Make sure you have everything you need and be very careful not to cut yourself when cutting.

    Step 3: Lay Out All of Your Pieces

    PVC placed and positioned
    PVC Placed and Positioned
    Guide marks keep you in check
    Guide Marks Keep You in Check

    Dry fitting the entire project beforehand is a great idea. You'll notice that some of the pieces may need to be sawed down to fit correctly. Take your time when lining up the handle; it can be a little tricky. Also make sure you keep everything level.

    Note: Draw out guide marks to help you know when you've pushed the pipe in far enough.

    Step 4: Assembly of the Base

    Getting Ready to GlueGetting Ready to Glue
    Assembly of the base   

    Start from the bottom and work upwards. You must work quickly – the PVC glue dries very fast. Spread the glue around the short pieces and inside the shaped pieces. Making sure everything is level, then push and twist together. If everything is not level, the later pieces you assemble will not fit.

    Tip: After inserting all the pieces, lay them flat on a table and push to make sure the whole base is level.

    Note: For a better seal where applicable, twist the PVC pipe while fitting together.

    Step 5: Assembly of the Other Pipe Pieces

    Assembly of the other pieces
    Assembly of the other pieces
    Using the same method as above, piece together the next set of parts:

    1 1/2" x 12" one on each side
    1 1/2" x 6 1/2" in the center

    Step 6: Glue the Pieces Shown

    Glue the pieces
    Glue the pieces

    Glue the pieces
    Glue the pieces
    Layout of Pieces to Be Glued Together

    Step 7: Setting the Handle

    Glue a piece 1 1/2" x 10" into the two T pieces. Set aside.
    Glue together part of the handle.
    Glue the two together.

    Step 8: Glue the Handle Piece into the Center Piece

    Glue the handle piece

    Step 9: Gluing the Cannon Ends

    Layout of the cannon endsLayout of Cannon Ends
    Layout of the cannon ends
    Glue them togetherGlued Together

    Step 10: Glue Cannon Barrel

    Layout the pipe Layout the Pipe for the Barrel
    Glue bushingGlue Bushing and Small Piece into Top of X Piece

    Step 11: Glue the Handle to Cannon

    Glue the handle Glue the Handle
    Glue small pieceGlue Small Piece into Small Elbow

    Glue elbowGlue Elbow into End of Handle
    Glue T piece into both small piecesGlue T Piece into Both Small Pieces
    Glue small piece into end of TGlue Small Piece into End of T

    Step 12: Attaching the Sprinkler Valve

    Glue male adapter pieceGlue male adapter piece as shown
    and use PVC tape for all screw fittings
    Attach electronic sprinkler valveAttach electronic sprinkler valve and insert other adapter.

    Step 13: Assemble Pressurizing End of Cannon

    Glue brass piece into PVCOn the opposite end, glue brass piece into PVC.
    Screw piecesScrew pieces in as shown.
    Brass pipe TBrass Pipe T (Remember to use PVC tape).

    Step 14: Continue with Pressurizing End Assembly

    Attach bike tire valveAttach Bike Tire Valve
    Attach Pressure GaugeAttach Pressure Gauge

    Step 15: Final Touches and Test Launch

    Before and after paintBefore and After Paint

    Paint your launcher and let it dry. Put a PVC 12" into the top where the marshmallow will be loaded and fired. Solder the wires from the sprinkler valve, switches and extra wire to battery pack and hide the battery in Altoids tin.

    One switch will be your safety, the other the fire. Load the marshmallows. Pump with bike pump to 30 psi. Flip your safety off and fire.

    Note: Take note that the marshmallow will go far, so make sure you have a safe area to launch them.

    Warning: Only pump the air cannon to 30 psi. Any more could result in damage to cannon or yourself.
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