Prop: TankAuthor: Marty RobertsReprinted from Crazed Imaginations #103. • These plans was originally shared at

The tank is Rocky’s womb, and an important prop for any cast. Many theaters don’t give you any place to store large props. This makes having a tank a challenge. But a collapsible tank can solve this problem. It can be stored under your stage or taken home by a loving cast member with a truck.

Midnight Insanity used this tank design for quite a few years. It was made to be collapsible for storage. One person can move it, if you don’t have to lift it onto the stage. I suggest putting a set of handles on the back and possibly some sliders on the bottom depending on what kind of surface you’re moving it on. When building your tank, you should cut your wood with each step. That way you can make any little adjustments you need to. Also you should ALWAYS pre-drill any screw holes. Pre-drilling will save you from splitting the wood.

A joist hanger. Credit: Marty RobertsTools: Circular saw • Jig saw • Cordless drill/screwdriver • Flat head screwdriver • Phillips head screwdriver

Materials: 10 joist hangers • 64 ¼” wood screws • 1 box of 1” coarse drywall screws • 1 box of 3” coarse drywall screws • 8 3” door hinges • 3 11/32” sheets of plywood (4×8) • 1 15/32” sheet of plywood (4×8) • 50 feet of 2×4 • 8 feet of 2×6

Pictured: A joist hanger. Credit: Marty Roberts

STEP 1: Building Your Base

The tank in the film rests on a base. So will yours. Start by cutting your wood:

  • 2 pieces of 2×4 Cut a 4’5 ½” length. Label these pieces: (A). These will be the long-side base pieces.
  • 2 pieces of 2×4 Cut a 21” length. Label these pieces (B). These will be the short-side base pieces.
  • 4 pieces of 2×6 Cut a 20” length. Label these pieces (C). These will be the vertical legs that connect the base to the tank.

A: Connect one piece (B) between two pieces (C) as shown. Make sure the edges are flush. (ILL 1A). Use two 3” screws to fasten the pieces together. Now repeat Step A on the other pieces of (B) and (C).

B: Next take one piece (A) and connect it to piece (C) on both ends. (ILL 1B.) Make sure (C) and (A) are flush on the side and bottom. Use three 3” screws to fasten the pieces together. Now repeat Step 1B with the other piece (A) on the opposite side of the tank.

Illustration 1A: One Base End. Illustration 1B: The Base. Credit: Marty Roberts

STEP 2: Building the Slab Frame

The slab is the bottom of the box-shaped part of the tank, and is what Rocky will lie on. It will need some support; the frame will provide that. These are the the pieces of wood you’ll need for this step:

  • 2 pieces of 2×4 Cut 6’3” long. Label (D)
  • 2 pieces of 2×4 Cut 25” long. Label (E)

A: Make a frame by placing two piece (E)’s between two piece (D). (ILL 2A.) Make them all flush. Use two 3” screws to fasten them together.

Illustration 2A: Slab Frame. Credit: Marty Roberts

STEP 3: Connecting your Base and Slab Frame

A: Lay the slab frame on the ground and place the base upside-down (with pieces ( C ) tops touching the ground) inside the slab frame. (ILL 3A.)

Measure 10 ¾” from the outside of the slab frame to the edge of piece ( C ) on the base. It should be the same on either end. Your base should now be centered in your slab frame. Fasten piece (D) to all four piece ( C )’s using 3” screws. Make sure pieces (D) and ( C ) are all flush on top.

Illustration 3A: Base and Slab Frame Connected. Credit: Marty Roberts

STEP 4: Slab Supports

You’ll need the following materials for this next step:

  • 10 joist hangers
  • 2 pieces of 2×4 Cut 21” long. Label (F)
  • 3 pieces of 2×4 Cut 25” long. Label (G)

A: Make sure that the tops of pieces (F) and (G) are flush with the tops of piece (D). Attach a joist hanger (using 1” screws) to both piece ( C )’s exactly opposite of each other, on the edge closest to the end of the slab frame. (ILL 4A.) Place one piece (F) in the joist hanger. Secure piece (F) in the joist by putting 1” screws thru the joist hanger into piece (F) diagonally (Step 4B). Now repeat this on the other piece ( C ).

B: Measure 11” from the support piece (F) towards the middle of the slab frame. Place your next joist hanger here on piece (D) and exactly opposite of it on the other piece (D). Put piece (G) in the joist hanger and secure it. C: Repeat step 4B on the other side of the frame. D: Measure 12 ¼” from either support piece (G) towards the middle of the slab frame. Hang your joist here on piece (D) and on the opposite piece (D). Place and secure your final piece (G).

Illustration 4A: Base and Slab Frame Connected. Credit: Marty Roberts

STEP 5: Laying Your Slab

You’ll need:

  • 1 4×8’ piece of 15/32” plywood.

A: This part is fairly easy. Place your 15/32” piece of plywood on top of the slab frame. Make sure that 2 edges of the plywood are flush with the slab frame (pieces (D) and (E) ).

Put one 1” screw in each corner to hold the plywood in place. Trace around the slab frame onto the plywood. Remove the screws and cut the plywood down to what you just traced, so it is the same size as the frame. (ILL 5A.)

B: Fasten your 15/32 plywood slab to the slab frame ( pieces (D) and (E) ) using 1” screws. Space the screws about 5” to 6” apart. Also fasten the slab to your supports (pieces (G) and (F) ) with at least one screw in the middle of each support.

Illustration 5A: Plywood Slab. Credit: Marty Roberts

STEP 6: Cutting the Tank Sides

For this step you’ll need:

  • 3 4×8 pieces of 11/32” plywood.

A: For the front and back: On one of your 11/32” plywood pieces lay out ILL 6A. Now cut it out. Place your cut out, with two side of it flush, on your 2nd piece of 11/32” ply wood piece. Trace and cut out. This makes sure that your front and back pieces are the same. Label one piece “Front” and one piece “Back.”

B: For the tank ends: On your 3rd piece of 1/32” plywood lay out ILL 6B and cut it out. Now take the piece you just cut and trace it on the remaining piece of 11/32” plywood and cut it out. Label these Side A and Side B.

Illustration 6A: Tank Front/Back Template. Illustration 6B: Tank End Template. Credit: Marty Roberts

STEP 7: Assembling the Tank

For this step you’ll need:

  • 8 3” hinges
  • ¼” screws

A: Lay Side A, Front, and Side B next to each other. (ILL 7A.) Measure 6” vertically up from the bottom of the tank. This is where you’ll put your hinge using ¼” screws. Do this on side A and Side B. Connect the hinges to the Front piece. Measure 4” vertically down from the top of the tank. This is where you’ll put your next hinges using ¼” screws. Do this on Side A and on Side B. Connect the hinges to the Front piece.
B: Pop the pins out of the hinges using the flathead screwdriver and remove side A and Side B from the Front piece. Put the Back piece on the ground and place Side A and Side B next to it like in ILL 7A. Make sure the edges WITHOUT the hinges are next to the Back piece. Now repeat Step 7A. Reinsert the pins in the hinges to re-assemble the tank.

Illustration 7A: Attaching Hinges. Credit: Marty Roberts

STEP 8: Connecting your Tank to the Base

The materials needed for this part are:

  • 8 1 ½” angles
  • 1” screws
  • ¼” screws

Now you are going to use the angles to attach the slab to the sides of the tank.

A: Place your tank around the slab. On the inside of the tank set the 1 ½” angles 1 ¾” out from each of the corners of the tank (where the Front and Back meet Sides A and B). You should have two angles in each corner, one on either side of it. One side of each angle should be sitting on the slab (don’t fasten them to it yet) and the other should lie along the inner tank wall. Attach the angles to the Front, Back, Side A, and Side B with the ¼” screws. (ILL 8A.)

Illustration 8A: Attaching Angles to Plywood Slab. Credit: Marty Roberts

B: Now secure the 1 ½” angles to the slab using 1” screws. (ILL 8B.) If you find the ¼” screws are too short for your liking, use longer screws, but nothing over ½” in length.

Illustration 8B: Angle Placement. Credit: Marty Roberts

To Disassemble:

  • Remove the pins from the hinges
  • Remove the 1/4” screws from the angles on the Front, Back, Side A and Side B.

There you go! You now have a tank. But wait! There’s still painting and decorating to be done! Well you get to figure this out yourself. I find that the most fulfilling part of building something is figuring it out. I don’t want to take that away from you, so you’re on your own with the rest of the project. I’ll give you a hint : paint it red.

Marty Roberts
Midnight Insanity
Head of Tech and Riff-Raff

#Author: Marty Roberts#Crazed Imaginations Reprint#Prop: Tank

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