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FAQs

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.)

How can I get rid of bubbles in Jesmonite?

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!

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.

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

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

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.

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.

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. Unfortunately colours cannot be specified in advance.

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.

How do I colour my Jesmonite?

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

How do I seal my Jesmonite creations?

We recommend our range of sealers designed to work with Jesmonite.

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.

Is Jesmonite dishwasher and microwave safe?

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