How sustainable friendly is Jesmonite? Your FAQs answered

Whenever we ask creatives, architects, or anyone else who uses Jesmonite why they love the product one of the main things that always crops up is the eco benefits of it. Jesmonite users do not need to have a controlled environment when using the materials as it won’t damage their skin or be harmful to their health, but we do advise wearing gloves and a mask when using large quantities. It is also not damaging to the environment; it doesn’t need chemicals and masses of room to use large equipment. But what else is it that makes Jesmonite so environmentally friendly? We asked you what you want to know on Instagram, and now we can tell you just that.

Can you tell us more about how sustainable/eco Jesmonite is please?

Jesmonite products are safe non-solvent alternatives to solvent based products such as fibreglass and polyester resin. They are also lightweight alternatives to heavyweight cast concrete and traditional stone.

Can Jesmonite be recycled?

Jesmonite products fall into two main categories: Acrylic Modified Gypsum Composites and Acrylic Modified Cementitious Composites. When recycling Jesmonite AC730 (water based micro-concrete) you would recycle it in the same way as traditional glass reinforced concrete. When recycling Jesmonite AC100 (water-based gypsum) you would recycle it in the same way as glass reinforced plaster. Cured Jesmonite AC100 and Jesmonite AC730 can also be broken down and used as decorative fillers.

What kind of material is Jesmonite?

Jesmonite products are composite materials, a combination of a reactive mineral base and a pure water based acrylic resin.

Is it fire safe?
Jesmonite AC730 is a two-pack water based, micro-concrete composite material. It is non-solvent, contains zero VOC’s and achieves an A2-s1-d0 EN 13501-1 (non-combustible) Fire Classification. Jesmonite AC730 contains a blend of decorative aggregates and pigments to achieve a range of stone and concrete effect surface finishes.

Is Jesmonite food safe?

We have not tested Jesmonite for food safety and do not recommend using Jesmonite in contact with food items. We’d recommend you do your own research into food safe sealers if you wanted to use it alongside food.

But it’s not just about sustainability and safety – we had lots of questions about technique too….

How do I get a super glossy finish?

Guard Industrie offer a number of stain, water and oil repellent sealers. You will need to run a small trial with the sealer first to make sure you’re happy with the product’s overall performance and appearance: Guard Industrie

What’s the best sealer? Besides your Acrylic, of course.

This will depend on which Jesmonite material you’re working with. You can find out about all of our sealers here: Jesmonite ancillary products

How to cure a big amount of AC100 at an even rate? Ie for a mantelpiece

In most cases Jesmonite AC100 can be de-moulded after 2-3 hours. Care should be taken at the point of de-mould, as the material can break if put under too much strain. Jesmonite AC100 is a water-based material and requires evaporation of any excess water to achieve full strength. Once de-moulded place Jesmonite AC100 in a warm, dry environment, dependant on thickness full strength will be achieved within 24 – 48 hours. Ensure that Jesmonite AC100 is placed on a suitable rack, or on surface where air can circulate.

What grit sandpaper would you advise to smooth after the initial sanding?

Jesmonite AC100 and Jesmonite AC730 can be sanded with a range of sandpaper grades. Users should investigate and trial the following sandpaper grit ranges:

60–80 Grit: Coarse.

100–150 Grit: Medium.

180–220 Grit: Fine.

320 Grit: Ultra-Fine.

How can we glue or join up two or more Jesmonite pieces?

You’re best off investigating a PU based adhesive, or an Epoxy based adhesive for bonding to cured Jesmonite elements. You will need to test the adhesive first to make sure it’s suitable and performs for the intended application.

Can you use acylic paint to create colour in Jesmonite?

We haven’t given this a go at Jesmonite HQ, however many other creatives have done this successfully. We’d recommend you do some tests first to make sure you are happy with the result.

What’s the best method for sanding and sealing Jesmonite?

Always wait 24-48 hours after de-moulding your products before sealing or sanding them to let the Jesmonite fully cure.

How do we easily know the mix ratio for a mould?

  • For casting Jesmonite AC100, every 1,000ml of mould volume will require 1,750g of complete mixed Jesmonite AC100 (1,750g Jesmonite AC100 = 1000ml).
  • For casting Jesmonite AC730, every 1,000ml of mould volume will require 1,850g of complete mixed Jesmonite AC730 (1,850g Jesmonite AC730= 1000ml).
  • The minimum thickness for decorative Jesmonite AC100 and Jesmonite AC730 terrazzo chips would be 2mm.

So, there you have it – hopefully giving you a little more insight into the benefits of Jesmonite and the way you can use it too. There’s plenty of creatives on social media sharing just what they do with the different products and how they’ve been experimenting too. We encourage you to look them up, see what they’re doing and have a go yourself too. Jesmonite is incredibly versatile and at the heart of everything is made, you know you’re being kind to the environment too.