As we introduce Jesmonite to our vast range of art supplies, we know many of you will be eager to start experimenting with this new and versatile medium.
To help you start creating with Jesmonite we’ve put together some key insights on the art material to guide you on your first try!
What is Jesmonite used for?
Jesmonite® AC100 is used for a wide range of casting and laminating applications including decorative cast objects, rubber mould support cases, polystyrene and foam coating, rigid moulds and many other areas in the world of moulding. A range of ancillary products are also available, extending the materials versatility.
How is it different to other materials?
-Stronger – Offers greater strength, flexibility and dimensional stability compared to traditional materials.
-Lighter – Lighter than plaster, stone, glass-reinforced concrete, sand and cement products.
-Safer – Independently fire rated in accordance with European Fire, Classification EN 13501-1, reduced smoke density and toxicity characteristics. Solvent free with no VOCs.
-Finer – Replicates the very finest detail.
-Greener – Water-based not solvent-based, making it kinder to the environment.
-More choice – Can be pigmented, mimic any texture and reproduce the effect of materials such as stone, metal, wood, leather and fabric.
Is it suitable for external use?
Jesmonite AC100 is suitable for internal and external use, however if used externally a sealer/suitable paint is recommended to protect surface.
How does one mix Jesmonite AC100?
The standard mix ratio for AC100 is 2.5:1 (2.5 parts Jesmonite Base : 1 part Jesmonite AC100 Liquid). It is essential to use accurate scales to weigh Jesmonite Base and Jesmonite AC100 Liquid and to mix using a Jesmonite High-Shear Mixing Blade. This blade can be attached to a drill with a variable speed control.
Slowly add the Base into the Liquids whilst mixing continuously at a low speed. As the remaining Base is added, slowly increase the mix speed to around 1,000rpm and mix for a further 30 – 45 seconds until the mix is smooth.
Adjustments can be made to the ratio for addition of additives such as stone and metal fillers, sands, lightweight fillers etc. It is also possible to mix the material at a 3:1 ratio to produce a fast set which can be used to fill joints, air bubbles, or to join castings.
Failure to follow these instructions can lead to strength loss, slow cure and reduced durability. Workshop conditions should be warm, dry, and out of direct sunlight. Environments where solvent-based compounds are in regular use should be avoided. Mixing containers should be clean and dry, and of a suitable size.
TIP: To calculate how much Jesmonite you would need for a project visit www.jesmonitecalculator.com
Can colour be added to Jesmonite?
Jesmonite has its own range of Jesmonite Liquid Pigments to add a pop of colour to your pieces. The Jesmonite Liquid Pigments are intermixable and can be mixed to create any colour. It is recommended to mix Jesmonite Pigments with a Jesmonite High-Shear Mixing Blade.
Jesmonite Pigments are added at a maximum of 2% by weight of the total mix, or 20grams/kg of total mix (Base and Liquid). 20 grams will produce a strong, saturated colour. For lighter colours simply reduce the addition rate until the desired colour is achieved. Note if you add too much pigment, it will stop the Jesmonite from setting or make the cast object weak and breakable.
If you want to cast a solid colour, mix the pigment into the pre-weighed AC100 liquids, blend thoroughly and slowly add the Jesmonite base to the liquids whilst mixing until the mix is smooth, flowing and free from lumps. Alternatively, you can add the pigment to the mixed Jesmonite, experiment by swirling it through to create different effects.
Any tips on casting?
For simple casts, pour a small amount of the mix into a mould and coat the surface evenly. To avoid any air bubbles on the surface, use a small clean, dry brush to coat the surface evenly and get into the edges of your mould. You can tap the mould too to get rid of surface air bubbles. Then fill up the mould with the remaining mixed Jesmonite, gentle tapping of the mould will help any air bubbles rise to the top surface.
Leave your cast for about 2-3hrs to set. Once you have taken it out of the mould, it will gain its full strength after 24 hours. Ensure that Jesmonite AC100 is placed on a suitable rack, or surface where air can circulate. Jesmonite needs all the moisture to evaporate to gain its strength, if you leave it in the mould it will sweat, may mark, and not dry thoroughly.
What about the surface finish?
Jesmonite AC100 can be polished with a clean cotton cloth and is also compatible with a range of water-based sealers and varnishes.
What additives are available?
Additives include the Jesmonite AC Retarder which can be added to the Jesmonite AC100 mixture to extend the pot-life/working time of the material. Should one wish to thicken the material consistency one can add Jesmonite Thixotrope to the Jesmonite AC100 mixture. It is recommended that both additives are mixed with a Jesmonite High-Shear Mixing Blade.
How should Jesmonite be stored?
Liquid containers should be kept well sealed to prevent water evaporation and skin forming. Freezing must be avoided and containers should be stored at a constant temperature. Base should be kept dry. Both Liquid and Base should be stored at 5 – 25°C and used within 12 months from the date of manufacture.
Any tips on cleaning up?
Because Jesmonite is water based, it’s easy to clean up when you have finished. Scrape any excess unused Jesmonite into the bin then wash your hands, mixing pots, brushes, and the mould in warm soapy water. You can use White Spirit to remove any pigment residue from your mould if necessary.
Jesmonite is now available from Vee Gee Bee Art! Visit our art shop in San Gwann for more info or view the full range of Jesmonite products online. You can even order your Jesmonite Starter Kit to start exploring the medium right away!
Have more questions? Give us a call on 2138 5584 or send us an email on [email protected]