How to make a Jesmonite vessel
Using Jesmonite AC100 and the water-fill method.
Jesmonite sets fast, so the whole job is about being ready before you mix. This guide walks through the full making session — working out exactly how much liquid and powder your mould needs, mixing and colouring it, pouring and cleaning up, demoulding, drying and waxing, then testing the finished vessel so you know it's safe to sell.
What you'll need
- ✦ Jesmonite AC100 liquid + base powder
- ✦ A silicone mould
- ✦ Digital scales
- ✦ A mixing jug + spatula or whisk
- ✦ Liquid pigment
- ✦ Gloves + paper towel
- ✦ Keep paper towel beside you before you begin.
- ✦ Never wash Jesmonite down the sink — it can set in your pipes and block them.
Calculate your mix — the water-fill method
- 1Fill the mould with water and weigh it.
- 2Add 5–10% to the water weight for wastage.
- 3Divide that by 2 — that's your liquid weight in grams.
- 4Multiply the liquid by 2.5 — that's your powder weight in grams.
Worked example
- Water weight = 155g
- Add 5% = 162.75g
- 162.75 ÷ 2 = 81.3g liquid
- 81.3 × 2.5 = 203.4g powder
The formula
- Water weight + extra % ÷ 2 = liquid weight
- Liquid weight × 2.5 = powder weight
- AC100 ratio = 2.5 powder : 1 liquid by weight
Measure, mix and add pigment
- 1Weigh your liquid and powder.
- 2Always add powder to liquid, never liquid to powder. Add a little powder at a time, mix thoroughly until smooth, then add more until it's fully combined.
- 3Once all the powder is completely mixed, add pigment in the colour of your choice.
- 4Lightly swirl for a marbled effect.
The mix sets fast — you only have a few minutes between mixing and pouring, so pour as soon as you can.
Pour and clean up fast
- 1Pour a bit at a time — it gives a smoother finish and helps prevent air bubbles.
- 2Tap the mould — then gently tap it on the work surface to move air bubbles upwards.
- 3Clean your jug and spatula with paper towel first — wipe out as much Jesmonite as possible before washing.
- 4Then wash in warm soapy water and set a 20-minute timer.
- ✦ If Jesmonite sets in a plastic jug, it usually has to be thrown away.
- ✦ Silicone jugs can sometimes be flexed clean.
- ! Don't wash Jesmonite down the sink before wiping it away with paper towel — it can set in your pipes and cause a blockage.
Demould and tidy
- 1Demould after approximately 20 minutes.
- 2If it still feels soft, leave it a little longer.
- 3Check the edges and surface.
- 4Once dry, lightly sand away any rough areas.
Let it dry, then wax
- ✦ Weigh the piece after demoulding.
- ✦ Then weigh it each day and record the weight.
- ✦ Once it stops losing weight, apply the wax — usually around 2–3 days after making.
- ✦ Apply finishing wax inside, outside and on the bottom.
- ✦ Use a sponge or cloth — a smooth makeup sponge works well because it has minimal texture.
- ✦ Buff on 2–3 thin coats.
Test your vessels
Before a vessel goes on sale as a candle container, burn test it and record what happened:
- ✦ Log the vessel wall temperature.
- ✦ Record flame height and self-extinguish time.
- ✦ Note any cracks or seepage.
- ✦ Mark the result as pass, fail or inconclusive.
Where Pour & Track fits in
The new Jesmonite section keeps the whole session in one place — save your recipe name, log the mould used, enter the water-fill weight and wastage margin, create your batch number and record the quantity made. The Test tab is where your daily drying weights and burn test results live, so every vessel style has a record behind it.
See the app guidesFree · 9-slide carousel · PDF
Tip: weigh your mould with water before you mix anything — it's the one number the whole recipe is built on.