How to Make a Jesmonite® Lamp: Step-by-Step Guide

Everything you need to make a Jesmonite® lamp

Our Make-your-own Jesmonite® lamp set has the whole project in one box:

• Light kit – E27 lamp holder + 1.8 m switch cable, in black or white
• Reusable silicone mould – round or triangle (you keep it and cast again later)
• Jesmonite® AC100 duoset – liquid + base, the exact amount for one lamp base
• Silicone feet to finish the underside neatly
• A free spare lamp, so you’re covered if the first ever breaks

You’ll also want a mixing cup, a stirring stick and a scale – plus, optionally, a few water-based pigments if you want to colour your lamp.

1– Choose your shape and cable

Pick the round mould for a soft, timeless silhouette, or the triangle for a more architectural look. Then choose your cable colour to suit the colour you’re going to pour – black for bold contrast with darker or richly-coloured casts, white to blend in with pale, pastel or white bases.

2– Weigh and mix your Jesmonite®

Jesmonite® AC100 mixes at a ratio of 1 : 2.5 (liquid : base) by weight. For one lamp base you need 500 g liquid + 1.25 kg base – which is exactly the small AC100 duoset that comes in the kit, so you already have the right amount measured out for you.

💡 Adding GlassRoxx, StoneRoxx or terrazzo chips? You’ll need a little less Jesmonite®, because the additive takes up part of the mix. Work out the exact split with our free Jesmonite® calculator.

It’s water-based and low-odour, so no gloves needed.

• Weigh out the liquid, add the base, and stir until smooth and lump-free.
• You have a comfortable 10–15 minute working window – no need to rush.
• Want colour? Add water-based pigment, up to 2% of the total mix weight. For a marble effect, add a few drops and swirl gently – the trick is don’t over-mix.

3– Pour and tap out the bubbles

Pour your mix into the mould, then tap the sides firmly for 20–30 seconds to bring trapped air to the surface. This is what gives you a clean, bubble-free finish.

4– Let it set (about 30 minutes)

AC100 is ready to demould after roughly 30 minutes. It will feel warm at this stage – that’s the normal setting reaction, not a problem. Quick test: press gently near the edge; if it holds its shape and doesn’t take a fingerprint, it’s ready.

5– Demould

Flex the silicone mould and ease the base out. Our moulds are thick and high-quality, so it takes a firm, confident flex – a bit of a wrestle here is completely normal, and it’s exactly what gives you clean, sharp casts for years to come.

6– Sand (optional) and assemble

For a plain cast, sanding is optional – but for an ultra-smooth finish, sand while the piece is still fresh and soft, as it’s much easier now than once fully cured.

💡 Added GlassRoxx, StoneRoxx or terrazzo pieces? Then sanding isn’t optional – you’ll need to sand the cured surface to bring the speckle and chips through to the surface. A medium (P150) sanding pad is perfect for this.

Once you’re happy with the surface, it’s time to assemble your lamp:

1. Press the silicone feet onto the underside.
2. Feed the cable up through the centre hole.
3. Attach the lamp holder and add your bulb on top.

7– Find its place

And that’s it – your lamp is finished! Find a spot for it in your living space – a shelf, a bedside table or a console – switch it on and enjoy the warm glow. Just handle it gently for the first 24 hours, while the Jesmonite® fully cures.

Tips for a professional finish

• Marbling: less is more – under-mix your pigment so the swirls stay distinct.
• One base, one afternoon: the kit makes one lamp base (the second lamp is a free spare bulb unit).
• Make more: the silicone mould is reusable, so you can cast lamp after lamp – just grab another small AC100 set (AC100SET-1750gr) plus a cable and lamp holder, and you’re ready to make another one.
• Indoor piece: AC100 is an indoor material – perfect for a living-room or bedside lamp.
• Want a rougher, concrete look? Cast your lamp in AC84 or AC730 instead – these cement-based Jesmonite® variants can be sanded or acid-etched (or gently etched with household vinegar) for a raw, stone-like finish.