An introduction to jesmonite
You’ve probably seen beautiful jesmonite crafts taking over your TikTok for-you-page, your Instagram feed or your Pinterest page. Those crisp, matte trays, jewellery or candle holders with perfect corners popping so-satisfyingly out of flexible moulds. An array of pastel or jewel tones, terrazzo and marble finishes – even gleaming with bright metallic flecks.
Assorted coloured jesmonite trays
Vintage tone hexagon coaster
Duo Candle Set
Black marble jesmonite plate
Gingko leaf jesmonite earrings
Pastel pink pen tray
Trinket dish slate green and plaster pink
Handcast jesmonite vase in slate green and plaster pink
But what…is jesmonite? Is it easy to make, and how do you get started? How do you know when to sand or seal jesmonite, and can you paint it? Is it food-safe? Is it toxic?
We’re going to answer all of this – and much more – so by the end of this post you’ll be ready to order supplies and get to creating (maybe even selling!) your ver own jesmonite creations.
Let’s start at the beginning…
What is jesmonite?
Jesmonite is a composite material (that just means it’s made of more than one component) that’s used in arts and crafts, as well as in some construction and manufacturing.
Simply put, jesmonite is a powder and a liquid, which when combined and left to solidify, turn hard and resilient. The powder is gypsum-based (gypsum is a soft mineral – it’s also used in chalk and plaster of paris), and the liquid is an acrylic resin.
What is it good for?
Because you start with a pourable, liquid mix (it’ll be about the consistency of double cream – that’s heavy cream if you’re in the US) – jesmonite is brilliant for using with silicone moulds (more on them later).
Is jesmonite food safe?
No, you shouldn’t use jesmonite for direct food storage like bowls or plates. But it’s non-toxic, so fruit bowls, platters (for food in wrappers) or similar are all on the table – metaphorically speaking. It also isn’t microwave- or dishwasher-safe.
Is it heat-resistant?
Only partly, so don’t use it for making trivets for hot pans. But it’s fine in direct sunlight or generally warm environments.
Is jesmonite chip-resistant?
It’s sturdy, but not as hard as substances like granite or quartz. So it shouldn’t be used in flooring, chopping boards or kitchen worktops. But for the tops of occasional tables, trays, jewellery and other decor items, it will stand up well. And because the colour is throughout rather than painted on the surface, even it chips it will still look good.
Can it be painted?
Yes! But you might not need to. Naturally, jesmonite is an off-white colour and it takes pigment brilliantly. Which means that rather than painting the surface, you dye the substance itself with liquid or powder pigments (more on these later). You can combine colours and techniques to make marble, terrazzo, watercolour and other beautiful effects.
Is jesmonite water-proof?
Let’s say splash-proof. Once sealed, you can wipe it clean with a damp cloth and use it somewhere it may occasionally get damp, but it shouldn’t be left in standing water – so vases or plant pots should have a waterproof liner to protect the jesmonite.
What can you make from jesmonite?
That just depends how creative you can be!
Popular options include…
- tea light holders
- soap dishes
- trinket dishes
How to get started
Here’s everything you need to get started with jesmonite casting:
- jesmonite – make sure you get a two-part product, base and liquid
- pigments (see below for options)
- moulds (see below for options)
- plastic sheeting to protect your workspace and make chips, if you choose
- cups or bowls for mixing
- wet and dry sandpaper in assorted grits
- beeswax to seal
Wet & dry sandpaper
Stainless steel mixing bowl set
Polythene dust sheet
Jesmonite 3.5kg kit
If that looks a little confusing, don’t worry! You can also get one of these convenient ‘starter kits’. They can be a little more expensive but set you up with everything you need to dip your toe into the world of jesmonite casting.
Now that we’ve got what we need, let’s get crafting! This is the most simple version of the process – once you’re confident, you can try more involved processes like making jesmonite terrazzo.
Terrazzo jesmonite coaster workshop
Jesmonite planter kit
Beginner’s jesmonite kit
DIY jesmonite coaster kit
Seal&Glow polishing set
Jesmonite casting starter kit
- Measure out 300g of powder and 120g of liquid. Mix together in a bowl. This is the magic ratio for sturdy jesmonite that sets properly – you can scale it up or down but keep the ratio the same
- Add your chosen pigments (more on these later) – less is more! Pigments are very powerful and you can always add more, whereas you can’t really take it away once it’s in there. To be really conservative, dip a cocktail stick in your pigment then dunk into your jesmonite mix and stir
- Once smooth, pour the mixture into your mould (more on these later, too). You want to ensure it’s in all nooks and crannies so tap the base gently on your work surface, and give it a gentle wobble to remove any air bubbles. Then leave for 30 minutes to an hour. Your mould might get warm as it sets – this is because jesmonite creates an exothermic reaction as it combines – but it won’t get hot
- Once set, gently ease your piece out of its mould. If your mixture flooded the mould successfully, there should be no holes or spaces from bubbles
- Use your wet and dry sandpaper to smooth your piece, starting with a courser grit and ending with the finest where you’re buffing the surface smooth. Keep adding a dash of water to your sandpaper to keep it wet so as not to damage the terrazzo. You’ll get a creamy paste coming away, but that’s helping you get a smooth finish
- Seal with beeswax or your choice of sealant by gently buffing a dab of it into the surface with a duster or clean cloth, and you’re done!
Pigments are intensely coloured elements – usually liquid or powder – that you add to a base substance to change their colour. With jesmonite, we tend towards liquid pigment as it’s easier to control, and to mix.
Pigments come in basic colours – primary colours, plus green, white and black is a common combination. But by mixing drops of pigment in your jesmonite mix, you can create any colour under the sun. It just takes patience – and practice!
Here are some great, basic pigment kits:
Fifteen mini pigment set
Six pigment kit
If you want to try something more adventurous, here are a few more creative options:
Neutral toned pigments
Neon powder pigments
You can also buy pre-made chips, pearl powders and metallic flecks for adding a little sparkle and flair to your jesmonite creations:
Winter-inspired mixed foil
Spring-inspired mixed foil
Gold foil flakes
Copper foil flakes
Bright crushed jesmonite
Crushed natural aggregates
Nude jesmonite chips
Terrazzo chips jungle & flamingo
Terrazzo chips coral & willow
Moulds for casting jesmonite
What sort of moulds should you use for casting jesmonite?
The most important thing is to choose a flexible mould – silicone or moulded plastic are the most common types. Advanced surface designers and artists make their own moulds, either by sculpting them by hand using scalpels and a rubber-like medium, or by using a high-tech piece of kit called a vacuum former, which will make a mould of any object.
But, as a beginner, you’ll want some ready-made moulds for your jesmonite activities. These are made up of one or several pieces which, when put together, create a chamber for your jesmonite to flow into. You leave it to set, then carefully peel away the mould.
A great way to find interesting moulds for jesmonite casting is to look for candle-making or even chocolate-making moulds, as the same principles apply.
Here are some simple moulds that are great for beginners:
Assorted tray and holder moulds
Geometric heart mould
Roman column moulds
Oval tray mould
Silicone coaster mould
Once you find your flow with jesmonite, you might want to experiment with more elaborate moulds to create ornaments…
Bubble cube mould
Geometric assorted moulds
Venus body mould
Zodiac sign mould
Moon face moulds
And as you build up confidence, you can combine shapes to make your own completely unique creations. For example, add a simple tray on top of a geometric column for an elevated stand – just join your pieces after sanding and before sealing, and use a high quality glue at any joins.
Some creative jesmonite project ideas
Want some more inspiration? Take a look at a few of the more advanced projects you could try your hand at once you find your feet with jesmonite casting – you’ll have beautiful pieces (and viral TikTok videos!) in no time…
You can create an incredible marble finish by adding tiny amounts of black pigment to your white jesmonite once in its mould, and lightly dragging a cocktail stick through the pigment to swirl rather than fully combine.
Combine jesmonite with clear resin and dried flowers for this amazingly contrasted piece. To make this happen, create a full jesmonite tray in your mould, remove and finish then carefully break it in two. Put half back in the mould and fill the remainder of the mould with resin, pressing in your dried flowers.
Add a couple of smaller round pots to a round tray to create a desk or make-up organiser, with separate areas for all your pens or brushes. Just cast the pieces separately then glue together.
Lightly swirl two contrasting colours together for a bold, modern and abstract look.
Can I sell jesmonite pieces?
There are lots of artists and creators who make a living from creating and selling jesmonite art. It’s a crowded field though, and important to learn the practice really well before you think about monetising it.
But if you do get there, start with a platform like Etsy that takes a lot of the upfront investment – in your own website domain, design and hosting – but charges more on a per-order basis.
That’s a whole other post though – next time…
Good luck creating!