Jesmonite has become a must-have material for making modern decorative pieces, candle containers, trinket dishes, trays and personalised accessories. Easy to work with, quick to set and with a beautifully clean finish, it opens the door to countless creations, whether you are just starting out or already an experienced maker.
Before you dive into a specific project, it pays to master the basics. In this guide, you will find every essential step for using Jesmonite properly: working out quantities, preparing the mould, mixing, pouring and demoulding, plus the good habits that give you a clean, long-lasting result.
These steps are the foundation of many Jesmonite creations. You can then apply them to a range of more specific tutorials.
Why learn the basics of Jesmonite?
Whatever you want to make, some steps never change. Measuring quantities accurately, sticking to the right proportions, avoiding air bubbles and giving your piece enough time to dry are all essential if you want a quality result.
This guide walks you through the general method to follow before you move on to more detailed projects. Once you have these basics down, you can easily adapt the technique to the mould, shape or project you choose.
The essential equipment for working with Jesmonite
For this example, we chose the AC100 range, the most popular and the easiest to work with.
Raw materials
- Jesmonite Duoset AC100
- Water
Equipment
- Beaker
- Precision scale
- Silicone mould of your choice
- Mixing container
- Sturdy spoon or spatula
- Vibrating plate (recommended)
The key steps to successful Jesmonite creations
1. Measure the capacity of your mould
Before preparing your Jesmonite, start by working out exactly how much material you need to fill your mould.
Place your empty mould on a precision scale and press the tare button so its weight is not counted. Then pour water into the mould up to the level you want.
The weight shown on the scale gives you an accurate measure of your mould's capacity. You will use this figure to calculate how much Jesmonite your piece needs.
2. Dry your mould thoroughly
Once you have your measurement, empty out all the water and dry your mould carefully.
This step matters because any trace of moisture can affect the final look. In particular, it can leave marks or whitish streaks on your piece.
3. Calculate your Jesmonite quantities
Once you know your mould's capacity, head to our Jesmonite calculator and enter the figure you obtained. The calculator gives you the amounts of powder and liquid needed to fill your mould in the right proportions.
Our online calculator lets you add a 10% safety margin. We recommend using it: it covers the small amounts of material left behind in the container or on the spoon while mixing, and makes sure you have enough Jesmonite to fill your mould completely.
4. Weigh the components separately
Place your beaker on the scale and tare it before weighing out the amount of liquid you need. Do the same for the powder, using a container large enough to mix in comfortably afterwards.
Once both components are weighed, get ready to mix. Jesmonite starts to set fairly quickly, so have all your equipment ready before you begin.
5. Mix until smooth and even
Gradually add the powder to the liquid, stirring all the time. Think of it like making pancake batter: adding the powder little by little helps prevent lumps from forming.
Stir with circular movements and scrape the bottom and sides of the container regularly. The aim is a smooth, even mix with no pockets of dry powder.
Ideally, use a spatula or a sturdy spoon to mix. We advise against using a whisk. It tends to work more air into the mixture and increases the number of bubbles in your piece.
Room temperature can also affect your working time. The warmer it is, the faster Jesmonite may set. If you would like more time to work your mix, you can use a suitable Jesmonite retarder.
6. Pour the Jesmonite into your mould
Once your mix is smooth, pour it gradually into your silicone mould. Pour at a steady pace so that every part of the mould fills properly.
7. Keep air bubbles to a minimum
Bubbles are one of the main challenges when making Jesmonite pieces. To keep them in check, ideally place your mould on a vibrating plate after pouring. The vibrations help bubbles trapped in the material rise to the surface.
If you do not have a vibrating plate, you can gently tap the sides and underside of the mould with your fingers. This can help bring some of the bubbles up, but it will never be as effective as a vibrating plate.
8. Allow the full setting time
Once your mould is full, let the Jesmonite set without moving your piece. How long you need to wait before demoulding depends in particular on the Jesmonite range you use.
AC100: around 20 to 30 minutes
AC84: around 2 hours
AC730: around 4 hours
The temperature of your workspace can change the setting time. In a warm room, Jesmonite may set faster. In a cooler room, on the other hand, it may need longer before it is hard enough to demould.
9. Demould your piece
Once the setting time is up, gently demould your piece. Even if it already feels solid, it has not finished hardening yet.
10. Let the Jesmonite cure for 24 hours
After demoulding, we recommend waiting around 24 hours before using or sealing your piece.
During this time, the Jesmonite keeps releasing moisture and hardening gradually. This waiting time gives you a more stable, stronger piece before you move on to the finishing touches.
11. Seal your piece if needed
Depending on how you plan to use it, you can then apply a suitable protective coating: Jesmonite acrylic gloss. This step is a must if your piece is going to hold wax.
Once the coating is applied, leave your piece to dry again for around 24 hours before pouring any wax into it or using it.
Recap: common mistakes to avoid when preparing Jesmonite
For a clean result, steer clear of a few classic mistakes from your very first pieces.
- Do not leave any trace of water in your mould before pouring.
- Do not start mixing until all your equipment is within reach.
- Do not demould your piece before the Jesmonite has set enough.
- Do not pour wax straight after demoulding. Give your piece time to harden and apply a suitable protective coating where needed.
Does temperature affect how Jesmonite sets?
Yes. Room temperature plays an important part in both the working time and the hardening of Jesmonite.
Warm environment: your mix may start setting sooner, so prepare all your equipment in advance and work in an organised way.
Cooler environment: Jesmonite may instead take longer to set fully.
Key takeaways
Mastering Jesmonite comes down to a few good habits: calculating your quantities correctly, getting your equipment ready before you start, mixing until smooth, keeping bubbles to a minimum and respecting setting and drying times.
Once you have these fundamentals in hand, you can easily apply them to all kinds of projects and experiment with new shapes, finishes and combinations. Use this guide as your go-to reference before each new creation.
Ready to put these tips into practice? Discover our tutorial for making a marbled floral Jesmonite candle container. With its marble effect, its lid topped with a raised peony and colours you can customise, this project lets you explore several techniques while creating a piece that is as decorative as it is practical.
