The Miniature Playground Project

In this instructable, I will lay out the construction process for three miniature playground installations - that were in fact part of a miniature playground project that I've recently finished. This project started with a photo tour of several public playgrounds in my hometown. I photographed about 10 different installations, some of which I already created as miniatures, for the purpose of building a miniature playground for my grandchildren to play with.

Using wood

For miniatures construction, I mostly use wooden plates and boards 1.8-2 mm thick. Where a thicker wood unit is needed, I usually cut and combine pieces from the above thickness by gluing them together. I also use ready-made wooden bars (round and square). My preferred type of wood for this job is Basswood, and sometimes I also use Plywood. I seldom use Balsa, as it is soft and prone to crumble, especially when it is cut in opposite to the direction of the fibers.

Additional accessories

Other materials may also come in handy, especially when I want to better capture a desired detail of the original installation. Here are some commonly used materials and accessories:

• Brass plates and thin brass rods.

• Metal wires with different thicknesses, and thin nails.

• Small metal jewelry accessories

• "Household" accessories such as metal grids, plugs, drinking straws, various plastic accessories, baskets, special packages, etc.

• Aluminum sheets that are cut from aluminum trays and folded later to create flat, rigid and flexible elements.

• Polymer clay (fimo, primo, sculpy etc.)

• Paints - mainly acrylic.

• I copy each of the installation pictures to a 100% scaling document to get the desired measurements.

• In general, the scale for the desired size is derived from Playmobil figures - a (7 cm) adult doll and a (5 cm) child doll. Using one of the figures, I resize the image of the installation in the document until it "matches" its size.

• As the installations photos are often taken from different angles, I make an assessment in order to complete various parts of the installation

• If the installation is complex and requires different motion mechanisms, I usually prepare a graphic model of it, according to the relevant size estimates. This can be performed with your favorite graphical editing software (personally, I use Adobe Illustrator).

Building the barrel:

1. Cut 2 units of balsa wood to the following sizes: L 2.6 X W 2.5 X H 1.4 (cm)
2. Using a drill with a suitable head (see image), make a straight groove along the 2 units.
3. Place a brass tube (see metal accessories image) in the center of the groove of one of the units, apply glue on the surface of one the units, and attach the other one to it. Wait a few minutes, then clamp gently the glued units (with table clamps) for at least 2-3 hours (see Image).

Building the other parts:

1. On a 2 mm thick wooden board, draw two circles of 2 cm diameter, cut them with a knife and file them well to achieve a smooth circle.
2. On the same board, draw an ellipse the size of L 2 X W 1.2 sm. Cut the ellipse into two parts along the longitudinal plain (these would become the handles eventually).
3. Cut about 20 matches (thickness 2 mm) in 3.2 cm length. (see image of the three elements)

Putting things together:

1. Drill a hole in the center of each of the circles, and glue them to the barrel unit - such that the hole in the center of the circle will match the hole in the barrel.
2. Using a sanding head, file the barrel into a cylinder, which will fit the dimensions of the two wooden circles attached to it (on the table clamps – see image).
3. Paint the two circles with a prominent color, and gradually glue the chips of the matches cut around the cylinder, in a way that exceed 1 mm on each side, just beyond the edge of the circles (see image).
4. Cut from the wooden board (2 mm thickness) the two support pillars of the barrel roll, sizes: L 4.5 X W 0.5 cm.
5. Prepare the base of the installation: L 7 X W 2.5 cm and 4 mm thickness. I have created the base from two identical wooden units of 2 mm thickness and attached them together with wood glue. Once dried and firm, you may want to smooth the edges on order to create a base with round corners.
6. Place the components of the device and the Playmobil figure on the PVC cutting pad and mark the precise spacing of the two support pillars on the base surface, along with the estimated position of the two handles – which will be placed between the support pillars and the figure’s hands. Also mark the height on which you will drill the holes in the support columns for the hinge will lie in.
7. Now paint all parts of the installation as you like. I recommend to paint the barrel and its wooden strips in "wood" colors (tints of brown color).
8. Adhere the support pillars perpendicular to the base of the installation and wait for total drying. Carving a small groove in the base would help to strengthen the glued pieces.
9. Cut a rigid metal wire (up to 1.5 mm thick). It should be able to pass through the hole in the barrel, and long enough so that its edges will stick out from both sides of the support pillars.
10. Place the hinge, which now carries the barrel, between the two support pillars. Make sure it is properly aligned and that the barrel is free to move without touching base of the installation.
11. Put a "lock" on the two sides of the hinge, by gluing it to perforated metal elements (tiny rings or metal beads that fit the wire diameter (see image). Be careful to not let the glue reach the barrel itself. if any excess wire is left beyond the "locks", carefully remove it with a pliers or (preferably) using a drill with a cutting disc.
12. Using the Playmobil figure once again, carefully measure the precise distance to the figure's hands when its standing on the barrel. If needed, you can adhere wooden shafts to the pillars in order to distance the handles a bit, and then adhere the handles to them (see last image).

The hammock swing installation consists of three main elements: (1) the hammock, (2) the wooden beams, and (3) the cables. Each of these three elements is made using different materials. I will describe the stages of dealing with each of the elements separately, and finally the way they are all put together.

1. The hammock

A. The polymer clay ring

To create a hammock ring, I used polymer clay. You can use one of the types I've listed in step 2 ("other accessories"), and of course any color you like (personally, I try to choose as close as possible to the photographed source).

1. On a carton board, draw a circle of 8.8 cm in diameter, and cut out the circle precisely. Take about 20g of Polymer clay, soften it tightly between your hands (or with a roll), and create a uniform cylinder about 6-7 mm thick, attach it to the edge of the carton circle to form a closed ring, while maintaining the integrity of the ring.
2. To simulate the rough surface of the original ring, I've punctured the ring with a toothpick.
3. Gently insert 4 hanging hooks, made of thin wire, into the clay (see the position in the picture). In order for the hooks not to be pulled out of the clay after baking, the wire must be folded at the bottom with the hook up (see picture).
4. Place the Carton with the attached clay ring on a baking paper within a baking pan, then put it in the oven for about half an hour (120ºC). Remove from the oven, and when the clay cools, pull out the carton.

B. The hammock mesh

To simulate the hard-plastic mesh, I decided to use about 40 small plastic zip tie bands. The edge of the plastic band has a slight bend, which allows to form the lower base of the grid. Each band should be cut 5 cm from its bottom, and only the lower part will be used (as shown in the picture).

1. Draw a 9.2 cm diameter circle on a carton board – this sketch will be used to mark the edges for constructing the mesh. The cut-off plastic bands should be gradually pasted together, using Super Glue, all bending from the center of the sketch and up to its edges (see picture).
2. After the plastic mesh is ready you must perform additional bending at all upper ends (see picture). These bent edges should be pasted, using super glue, to the clay ring (see picture).

2. The beams

The beams should be cut from round wooden rods (10 mm diameter). The length of the 4 lateral beams should be 17 cm, and the length of the top beam should be 18 cm. Each two beams should be pasted together in a manner that satisfies all the other measurements depicted in the installation model (see sketch picture).

1. Paint the beams (preferably with "wood" color, or clear varnish).
2. Paste together each pair of beams - follow the sketch model in the picture for specific measurement details.
3. In order to strengthen the grip between each pair of lateral beams, a small flat groove should be carved into the contact area between them, on each side of each one. This can be easily achieved using manual filing and will allow the pair to stick together on a flat surface, rather than a round one.
4. After drying for 4-5 hours, the bottom part of the lateral beams should be filed in a manner that will allow the beams to be placed parallel to the ground (see sketch picture).
5. For the top beam, two hanging hooks shall be made of 1-1.4 mm thick metal wire (about 5 mm long). Each hook is to be placed in a pair of holes, drilled 3 cm from each end of the beam. The hooks should be glued to the holes using Super Glue Adhesive.

3. The two cables

Each of the two cables is made up of a number of components, connected the following order: The upper beam hook - a link chain (3 cm) - the cable clip - two cables (6.5 cm) - the lower two clips - and the two hanging hooks, which by now should already be part of the clay ring (see picture for full details).

Putting it all together:

1. Connect the parts of the cable to the top beam (not yet affixed) as specified above. The upper clips will be connected to the edge of the link chains (you should be able to open the link with a needle nose pliers, and then close it back after it is inserted into the clip).
2. Place the top beam on the cross of the two lateral beams and adhere it to them with wood glue.

The carousel is constructed of four main circles: (1) the base surface, (2) the seating surface, (3) the railing and (4) the wheel in the center. From a side view, the three central blocks resemble an truncated cone (see picture).

The size of the circles:

• The railing - external diameter: 9.4 cm, width 0.2 cm, thickness 0.4 cm
• The seating surface - external diameter 8 cm, width 2.2 cm, thickness 0.2 cm
• The base circle – diameter 7 cm, thickness 0.2 cm. To strengthen the base circle, an additional "reinforcement" circle of 5.8 cm in diameter and 0.2 cm in thickness will be added underneath.
• The power wheel – diameter 1.6 cm, thickness 0.2 cm.

A few pointers for making the circles:

• Draw the various circles on a 0.2 cm thick wooden board.
• For the railing circle, use a double wooden ring to obtain a thickness of 0.4 cm (two rings with a diameter of 9.4 cm, pasted together).
• The "reinforcement" circle should be pasted exactly below the center of the base circle.
• Using a knife, cut all the circles on the external edge (and internal, if necessary), then file them manually or using a drill with a grinding head. This goes for the edges of the glued railings as well.
• The inner part of the seating circle should be cut and removed, then filed on both sides.

The motion axi

1. In the center of the reinforced base circle, drill a hole to fit a 2.5 mm metal cylinder. This cylinder will be later the drive shaft will be inserted, thus connecting the base to the power wheel.
2. The length of the cylinder should be 3 cm, of which 4 mm would be inserted into the base circle, and another 2 mm on the other end will be inserted into a hole drilled in the power wheel.
3. It is recommended to strengthen the cylinder into the circles using Super glue and keep all parts properly aligned.

The ground base unit

This unit can be given the shape of a square, circle, or a "star" (as I preferred). In any case, it is very important that the perimeter of this unit will be larger than the perimeter of the base circle, in order to ensure stability.

1. For construction, use a 4 mm thick plywood (which can also be constructed by attaching two units of 2 mm).
2. In the center of the unit, drill a hole (1.5 mm in diameter) and insert into it a nail of the same diameter, 3 cm in length.
3. The head of the nail should be concealed within a small groove in the base unit. The tip of the nail, which should be slightly truncated and smoothed, is inserted upward, and will form the motion axis of the installation.
4. The nail should be reinforced to the unit using Super glue.
5. In order to reduce friction between the ground base unit and the base circle, paste a small metal washer to the surface of one the units.

The upper part of the carousel

Now the three components of the upper part should be brought together: the base circle, the seating circle and the rail.

1. Three narrow support units should be created for the space between the railing and the seating circle, and another three, slightly wider units, should be created for the space between the seating circle and the base. The structure of the units can be seen in the diagram, and in the picture.
2. The support units can be constructed from the joining and pasting of two units (2 mm thick).In addition, two small horizontal support triangles should be attached to each connection point between the support units and the rail (see final image)

Finishing:

1. Paint all parts of the carousel
2. Paste the support units. First, paste the narrow support units to the upper part of the seating circle, and then, after full dry, paste them to the railing above. Wait for full dry, then paste the wider support units to the bottom the seating circle, aligned with the position of the narrow units above them. Wait again for full dry, then paste the lower side of the support units to the base circle underneath.
3. Finally - place the carousel on the motion axis and rotate away.. :)