Dots: a Cement-base Lamp

This is a great indoor decorative lamp that could go well as a warm ambient light in your living room or bedroom.

It all started when I began experimenting with white cement and the different textures that were possible with the least amount of materials, and ended up with an interesting combination of textures, materials, colours and patterns.

My experiments with white cement began as I was looking for an extremely low-cost, low-effort way to dive into casting and mould-making.

All the materials I have used are sourced locally, so I will try my best to give their generic names wherever I can, and, since I am unable to suggest any particular brand or place where you can buy these materials.

The project can be divided into 8 parts:

1. Preparing the mould
2. Pouring the white cement mixture
3. Demoulding
4. Finishing
5. Painting the cement base
6. Painting the glass bottle
7. Light fixture
8. Electrical wiring.

- 1 x Outer bowl - this will form the mould (any plastic container that is sufficiently flexible should do, no restrictions on size, but be sure that it is proportionate to the lamp shade)

- 1 x Inner bowl - this will be the core of the mould (any plastic container that is sufficiently flexible, and is proportionately smaller than the outer bowl)

- 1 x Textured plastic sheet (optional)

- 1 x Glass bottle with lid

- 1 x PET bottle lid

- 1 x Mixing bowl - to contain the white cement mixture

- 1 x Ice-cream stick - to thoroughly mix the white cement and water

- 1 x White cement bag (1kg)

- Water (1 litre)

- 1 x Filled water bottle (1.5 litre) (this should fit inside the inner bowl)

- 1 x Cellotape

- 1 x Double-sided tape

- 1 x Pliers

- 1 x Heavy-duty cutter

- 1 x Fast-curing epoxy adhesive

- Acrylic paints (green, white, metallic copper, or any colour of choice)

- Neon paints* (optional) (neon orange, neon pink, neon green, or any colour of choice)

- Paint brush (1 for each colour)

- 1 x Electrical wire for bulbs (1m)

- 1 x Light bulb (yellow, or any colour of choice)

- 1 x Light bulb holder

- 1 x Electrical plug

Take the outer bowl.

Place a plastic sheet for texture inside the outer bowl.

I've used an old sheet of bubble wrap for the texture, ensuring that there are enough bubbles intact for the texture I'm going for.

Place the metal lid of the glass bottle inside the outer bowl at the centre.

If you're using a textured sheet, place the glass bottle lid on top of the sheet, at the bottom of the outer bowl.

For good measure, so that the lid doesn't float around when you pour the white cement, use multiple layers of double side tape to hold the lid in place.

The inner bowl is used to mould the hollow part of the cement base.

Turn the inner bowl upside down and use cellotape to paste the PET bottle lid on the bottom of the inner bowl.

The PET bottle lid will create a cavity in the cement base just wide enough for the bulb holder to sit on the cement base.

Place the inner bowl with the PET bottle lid inside the outer bowl.

You may use a rolled up piece of cellotape to hold the PET bottle lid against the metal lid of the glass bottle stuck at the bottom of the outer bowl.

Add up to 75% of the inner bowl volume of white cement into the mixing bowl. It helped me to follow this thumb-rule so as to avoid mixing more white cement than needed, and also to avoid the mixture from spilling over while mixing.

(Here, my inner bowl and mixing bowl are of the same volume)

Add water gradually. The consistency of the mix should not be runny, but it should be just enough for you to prod the mixture into the mould with the ice-cream stick.

Stir the mix vigorously to avoid lumps and ensure it is smooth.

Watch the video to get an idea of the consistency I've used for the mould.

Pour the white cement mixture into the mould.

Tap it against the table to let air bubbles trapped in the mould surface, and ensure the mixture gets inside the crevices.

Be careful not to let the inner bowl float.

Place the 1.5 litre bottle of water inside the inner bowl, to prevent the inner bowl from floating on the white cement.

Set this aside for about 24 hours.

Gently pry the cement casting away from the plastic sheet and the bowls, and remove the PET bottle lid from the casting.

If you want to see the process of removing the casting from the mould, watch the video.

The inner bowl seems to have floated away and the white cement has gotten under the metal lid.

In case this happens, use a heavy duty cutter knife to cut the soft white cement away from the lid.

This process takes about 5 minutes and a set of pliers might come in handy to pry the pieces of white cement from the inner surface of the lid.

Watch the video to get an idea of how the glass bottle now screws on to the cement base.

Mark an "x" across the diameters of the lid and use a heavy duty cutter to cut across the lid.

If you look closely at the metal lid, you'll find that the centre of the lid is the weakest as the metal sheet is the thinnest. This part is often quite easy to cut. It so happens that this part is just the right size for the PET bottle lid-shaped hole in the casting, where the bulb-holder will sit.

Use a pair of pliers to twist the cut lid away from the lid.

Watch the video to see how I did this.

Test out the assembly.

Next, we're going to work on the flaws in the cement casting.

Mix about a teaspoon of white cement with twice as much water to make a thick paste.

Apply this thick paste on the craters and pores of the casting.

Smooth the paste over all the craters and pores with the ice-cream stick or a dry finger.

This sets in a few minutes.

For my design, I've used a sea-green base coat on the cement base - a mix of white and dark-green acrylic paints. This tint of green goes well in contrast with the neon pink and neon orange colours I'd used for the glass bottle. However, I found this colour to be absolutely difficult to capture on camera and will appear more blue in pictures.

Mix paints thoroughly.

If you're using a colour that does not need to be mixed and can be used straight from the bottle, you may skip this step.

Watch the video to see how I've mixed the colours.

Apply the paint evenly over the cement base.

Be sure to get the paint inside the grooves and crevices, if you're going ahead with texture.

Here's a process video of the painting. It took about 30 minutes to prep the colour and paint the base.

I wanted to go for a look that reveals the texture, but the contrast shouldn't be too overwhelming.

So I used metallic copper for a slightly rustic but richer look. Since the contrast between metallic copper and sea green is high, I added another layer of a texture to reduce the contrast.

Dry-brushing.

I used an old dry, wide paint brush with rough bristles, dabbed on some metallic copper acrylic paint, and held the brush vertically over the cement base, in a "dusting" motion, in multiple directions.

Check out the video to see how I've used the dry-brushing technique. This step took about 10 minutes.

The result was an unevenly painted metallic copper, that highlighted the texture without adding too much contrast.

I had moulded a deep crevice down one side of the cement base and the dry brushing technique revealed the crevice beautifully, quite similar to a coral reef, as a friend pointed out.

I wanted the light to be more diffused than sharp, so I tried finding ways to enable diffusion through the glass bottle shade.

You could either sand the surface of the glass bottle using 100-800 grit sandpaper, increasing the grit at each stage. -- I am yet to try this technique, but I imagined that this would be a lengthy process and I did not have access to sandpaper of varying grit.

I was curious about exploring the materials I had at my disposal and wondered what would happen if I poured diluted white cement down the glass bottle and let it dry.

This is the result of that experiment.

Mix white cement and water to a watery consistency. Stir vigorously to avoid lumps.

Pour the diluted white cement mix inside the glass bottle, close the lid tightly and shake the bottle thoroughly.

At this consistency, there may be small lumps that often stuck to the sides of the bottle, so be sure to shake the bottle thoroughly and let it settle.

Watch the video to get an idea of the pouring consistency of the white cement.

Pour out the excess white cement mix from the bottle.

Let it rest, upside down for about 5-6 hours, before you continue to the next step.

The result is a fascinating network, very similar to pattern river basins make on a physical map, to veins on a leaf, to the fibrous roots of a plant.

Watch the video to see how the pattern developed around the bottle.

Using a cutter or a blade, scratch off any paint that may be on the bottle

It's always good to have a trial of the pattern you'd like on the glass bottle.

Since the texture on the white cement is circular (from the bubble wrap), and the bowl is mostly round, I went ahead with a geometric pattern across the length of the bottle.

Choice of colours - yellow, orange, shocking pink, and neon orange, neon pink (not neon yellow), lighter tints of blue and green work well. Darker shades of blue and green, purple, maroon etc. hide light and these colours are not very visible against the light from inside the bottle.

You may use a marker to mark out the negative space in your pattern. This can be wiped off quite easily with a wet cloth.

Paint your pattern on the glass bottle!

I used dots applied with the back of a size 0 and size 1 brush - 1 brush for each colour.

The trick with using acrylic paint on a backlit glass bottle, is that it is hard to spread the paint evenly over the glass surface. The uneven consistency of the paint is visible as silhouettes. Hence, I used a dot technique to apply the paint on the glass bottle.

I took about 20 minutes for my pattern, careful not to hold the bottle where there's fresh paint. Check out the video for a glimpse into this process!

The bulb holder usually comes in 3 parts:

1. the part that covers the base of the light bulb
2. the part that holds the bulb securely and connects it with the electrical wires, either with a pin socket or a screw socket.
3. the part that covers the electrical wires coming out of the bulb holder.

Unscrew parts 1 and 3 and keep them aside.

We will be using parts 1 and 2 for this project.

You may use an epoxy based adhesive for fixing the bulb holder to the cement base

These come as 2 components - a resin base and a hardener.

Cut equal parts of the resin base and hardener.

Roll the 2 pieces in your palm. Once they become long, fold it over and roll again.

Repeat this process until the epoxy adhesive compound has a consistent colour (black, in this case).

Roll the compound into a thin long strip and roll it on the thread of the bulb holder.

Place the bulb holder with the adhesive into the hole in the cement base.

Refrain from pressing it down.

Turn the cement base right side up and ensure that the bulb holder is perfectly straight.

Turn the cement base over, upside down and press the bulb holder down, smoothening the adhesive on to the cement base and filling the gaps.

(I did not have access to a wire-stripper, so I had to use a blade. I highly recommend that you use an electrical wire stripper for this step, for an easier and higher quality work)

Strip the insulation from the ends of the electrical wire, as shown.

Repeat this step on the other end of the wire too.

Unscrew and open the electrical plug.

Screw in the electrical wire in to the 2 plugs.

Close and screw back the plug, ensuring that the wires don't get in the way.

I made a mistake at this step, and unknowingly screwed the plug shut with the wire stuck in between, the insulation ripped.

There was a mini-explosion at my house as the wires shorted and the fuse blew.

So, I strongly advise caution in this step.

Take the part that is used to cover the base of the light bulb.

We'll be using this as the stand for the cement base to rest on.

Pass the electrical wire through this part.

Fix the electrical wire ends into the bulb holder.

Screw on the base of the light fixture.

I made a small cut on this part with a heavy duty cutter for the wire to pass through safely to outside the cement base.

Connect the bulb to the bulb holder, the plug to the socket.

Switch on the light.