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Jesmonite FAQs

Q. What are Jesmonite products made from?

Jesmonite is made by Jesmonite Limited in the UK and shipped around the world. It is a composite material which combines a reactive mineral base and a water-based acrylic resin.

Q. What can Jesmonite be used for?

Jesmonite products are used within a wide range of decorative markets including craft, tableware, artwork, sculpture, lighting, furniture, marine vessels, film sets, architectural elements and cladding panels.

Q. How should I store Jesmonite?

Liquid containers should be kept well sealed to prevent water evaporation and skin forming. They should be stored at a constant temperature between 5°C– 25°C and used within six months. Freezing must be avoided. Base powder should be kept dry and stored at 5°C – 25°C.

Q. How do I mix Jesmonite?

To properly mix Jesmonite liquid and powder together you will need a Jesmonite High-shear Mixing Blade, which is specifically designed for mixing Jesmonite. The mixing action reduces air bubbles and ensures that the mix is smooth and free from lumps. Two sizes are available, 65mm and 105mm for different mix sizes. They are made from stainless steel, and will attach to all conventional drills.

Q. Is Jesmonite safe?

All Jesmonite products are water based, non-solvent and contain no VOCs.

Q. Is Jesmonite food safe?

Jesmonite is non-solvent and contains zero VOCs, however, it has not been tested for food safety.

Q. Is Jesmonite dishwasher and microwave safe?

It is not advised to use Jesmonite in a dishwasher or microwave.

Q. Are Jesmonite products fire tested?

Jesmonite products have been tested in accordance with EN 13501-1 under the harmonised Euroclass System of reaction to fire performance of building products which has been adopted by countries across Europe.

Q. How do I clean silicone moulds after using them?

To clean the moulds after use, rinse with warm soapy water, and dry thoroughly before using again. For the best possible clean we recommend Grimex wipes – they are great for removing every trace of dirt and dust.

Q. How do I seal my Jesmonite creations?

We recommend Jesmonite Acrylic Sealer, which is a durable, flexible, and UV resistant pure acrylic coating.

Q. How do I colour my Jesmonite?

Jesmonite can be pigmented to any colour required using Jesmonite Pigments.

Q. How much pigment should I use?

Pigments should be added to a maximum of 2% by weight of the total mix, or 20grams/kilo of total mix (Base and Liquids). 20 grams will produce a strong, saturated colour. For lighter colours simply reduce the addition rate until the desired colour is achieved.

Q. What pigment colours will I get in the AC100 Starter Kit?

Starter kits are packaged and sealed by the Jesmonite factory and will contain a selection of 3 pigments.

Q. What type of textures can be achieved with Jesmonite?

Jesmonite can mimic nearly any texture and reproduce the effect of materials such as stone, metal, wood, leather and fabric.

Q. What is a good adhesive to use with Jesmonite?

To bond cured Jesmonite you will need to either an epoxy or PU based adhesive. Most of our customers find that 2-pack epoxy adhesives adhere better than 1-pack adhesives.

Q. Is Jesmonite heat and flame resistant for creating products such as incense holders and candles?

No. We recommend exploring using a burn-proof sealer.

Q. Is it safe to buy Jesmonite off Etsy?

Buying from unapproved distributors is risky, as Jesmonite has a shelf-life and it’s impossible to know how long the original containers have been open for. We always recommend buying from an approved distributor, like Polysil.

Q. How can I get rid of bubbles?

You can reduce the bubbles in your Jesmonite work in a few ways:
1. Make sure your mix is made to the correct ratio.
2. Blend your mix for a minimum of 2 minutes using a Jesmonite mixing blade (attached to a drill).
3. Brush a 1-2mm coat of Jesmonite onto the mould (make sure your brush is clean and dry.)
4. Vibrate and tap the mould to bring air bubbles to the surface.
5. Fill the rest of the mould and repeat tapping. This is easiest if you don’t overfill your mould!
6. Pop air bubbles by blowing.

Top Tip: Use a straw to direct your breath better!


Silicone Rubber FAQs

Q. What types of silicone rubber do Polysil sell?

Polysil sell RTV Silicone Rubber F23 and Silicone Rubber (Genuine 3841). Both have similar properties with excellent fluidity, low shrinkage, good strength and easy demoulding. The 3481 has some advantages that are more suited to the professional user:
– The material is German made using only the finest raw ingredients.
– Mechanical properties such as tear strength and elongation to break are superior.
– Proven archive life (i.e. The rubber can be stored for future use and will retain strength and elasticity.)

We stock two different types of 3481, one can be used with a Thixo additive.


Shipping FAQs

Q. Can I get Jesmonite in the US?

No. There are currently no distributors in the US.