Introduction: Pebble Cactus

Hello everyone and welcome to my fourth instructable!

I like very much plants and flowers but I do not really have a "green thumb"...

this is one of the reasons why I love cactus (or cacti)! They are absolutely my favorite among the plants and I find some of them real artworks: elegant like pieces of furniture, never banal with their strange shapes and, as I was saying before, they last long and require low maintenance.

But do you know what is quite eternal, even more than a cactus? Stones!

So, let's build a faux cactus made of pebbles!

Step 1: Materials and Tools

To build it:

  • workbench or vise
  • hammer
  • 1 wood screw
  • drill or rotary tool (or both)
  • 2mm/3mm/4mm drill bits (for the type of bits, see "step 3")
  • 1.5mm/2mm steel wire
  • caliper
  • cutting nippers
  • lineman's pliers
  • hot glue gun
  • primer and spray paint
  • pencil and permanent marker

To plant it:

  • a terracotta pot
  • a piece of thin wood
  • a wall plug with its screw
  • 2 washers
  • something to cut a circle out of wood: I use a hand saw and file but you could use also a drill with hole saw or even a jigsaw

Step 2: Find the Right Pebbles

I am lucky to live very close to the sea and the beaches, in my area, are mostly made up of pebbles. They are certainly not as comfortable as the sand when you lie on it but, hey, free pebbles!

The search for the right stones must be done having in mind the project that you want to create.

In this case I would like to recreate a prickly pear, so I'll have to look for stones that look as close as possible to the leaves of this plant: quite flat and with a shape similar to a triangle with very rounded corners. The first leave should be quite big (it will be our base), then they get smaller as you go up.

Do not forget the fruits: they are like olives a bit squeezed at the ends, if they were people I would call them "stocky and chubby".

Take also a few handfuls of very small stones, like gravel, to cover the base placed in the pot.

I am certainly not an expert in minerals or stones, so I can not tell you which are the easiest pebbles to drill. What I can tell you is that you will drill some stones very easily while others will annoy you. And some of them will chip or break. So, I suggest you to take a lot of pebbles, just in case..

Step 3: Find Your Configuration

Position your pebbles on a flat surface and try to find the configuration you like.

When you find the perfect one, I suggest you to mark with a pencil (but also a fine-tip marker) the line that "connects" the two stones. This will be a a good reference to follow later for drilling and assembling your pebbles.

Step 4: Drill the Holes

Before beginning to drill, a small clarification about drill bits I use:

  • small pebbles: 2mm carbide tungsten drill bit, works great!
  • large pebbles: 3mm masonry bit, since I could not find the prevoius type in this size
  • base pebble hole: 4mm masonry bit (same reason as before) in order to insert a wall plug (Fisher) that will hold the whole cactus.

Lock your pebble in the workbench or in a vise with the line you made before facing up.

Mark the point you want to drill by gently hammering (pebbles are hard but also very fragile) a wood screw.

Usually I make a 10mm deep hole for big stones and a bit less for the smaller pebbles marking, as a reference, the required lenght with a piece of masking tape on the bit.

I suggest you to wet the bits from time to time to cool them and make them last longer.

Step 5: Prepare the Wire and Assemble

Insert the wall plug in the base pebble and screw the screw in it for about half of its lenght.

We are ready to "assemble" the cactus. For the connection we will use steel wire (1.5mm and 2mm) and hot glue.

The small pebbles need only a piece of 2mm wire as they do not weight much. For the bigger ones, we will use two pieces of 1.5mm wire twisted together. I think this solution is even better than a bigger wire because the coils combined with glue will lock perfectly in the hole.

    Cut two pieces of wire of the same lenght.

    Keep one end with a lineman's plier and begin to twist the two wires with your hand. As it becomes hard to proceed with bare hands, continue to twist them with another plier. Finally, straighten them with the hammer.

    Done this, cut a piece of more or less 20mm and insert it in the hole of the first pebble, pushing down until it reaches the bottom. Then, do the same with the other pebble. If there is any surplus, measure it, extract the wires and cut them.

    Pour some hot glue with the gun and immediately, before it solidifies, plug in firmly the braided wires.

    Remove the excess of glue and do the same with the other pebble.

    Your first connection is done!

    Continue with the others pebbles and compose your indian fig. Except for the fruits: prepare them with the hole and the wire but do not link the to the rest of the cactus because we will paint them apart.

    Step 6: Paint Your Cactus

    Before beginning to paint, use some plaster to fill the gaps between one pebble and another, trying to smooth it as much as possible. When it dries, we will be ready to paint.

    Make sure that the wall plug is securely locked in the base pebble (if not, tighten more the screw).

    Turn the whole cactus upside down, tie a string on the base screw and hang it. Mask the screw to avoid to paint (and thicken) it.

    Spray a few layers of spray stucco or a good primer. Then, paint with a proper green. If you want, you could shade the smaller "leaves" with a lighter colour.

    Paint also your "fruits" in red with yellow nuances.

    When all is dry, with the same technique as before, mount the fruits on the rest of the prickly pear.

    Step 7: Prepare the Base and "pot" Your Cactus

    Measure the diameter of your terracotta pot, draw on the thin wood (I used a piece of scrap wood) a circle a little smaller than your pot and cut it.

    Try it in the pot and adjust it until it fits perfectly, maybe flaring it a bit.

    Drill a 4mm hole in the center of the wood disc.

    Insert in it the base screw, adding two washers, one above and another below.

    Tighten firmly the screw in the wall plug placed in the bigger pebble.

    It's time to "pot" our cactus by simply pushing down the wood base until it gets stuck.

    Step 8: Add the Last Details

    Draw the thorns with a permanent marker and any other detail you want.

    Even the ladybugs will mistaken it for a real plant!

    Lastly, add a handful of gravel to cover the wood base and create a perfect "set" to your beautiful, forever lasting, prickly pear!

    Step 9: Create!

    Here are some examples of my previous creations.

    Enjoy making other types of pebble cactus!

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