The Jesmonite AC100 Retarder is a specialist additive designed to extend the working time of Jesmonite materials within the AC100 - AC300 range, giving you greater flexibility during mixing, casting and finishing. It is particularly useful for detailed work, larger pours or warmer working environments where Jesmonite can begin to set more quickly.
The retarder is added in small, controlled amounts during mixing to adjust working time to suit your project. Typical usage levels range from a few grams per kilogram of mixed material, allowing you to fine-tune performance based on project size and complexity. Actual setting times will vary depending on ambient temperature and humidity, so test mixes are recommended before full production.
Formulated specifically for the AC100 - AC300 product range, this retarder helps slow the setting process without negatively affecting the final strength or surface quality when used correctly. Please note that retarders are range-specific - this product is not suitable for Jesmonite AC730, which requires a separate retarder.
Supplied in a 1kg container, the Jesmonite AC100 Retarder is ideal for professional studios, workshops and serious makers who require consistent, controlled results when working with Jesmonite.
Not suitable for AC730 (separate retarder required).
Code: 12068
Customer Reviews5.05 5.0/5 Based on 1 review
Brilliant productReviewed by Rachaelhillson73 on 13 Jul 2025
Second time using this company and can't fault them .. this product is absolutely amazing and worth every penny
Fibreglass Supplies use Royal Mail, APC Overnight and the National Hazardous Pallet Network for our Next Day Delivery Services.
Royal Mail
Orders of up to 2kg will usually be sent using a Royal Mail First Class Service for National Next Day Delivery.
APC Overnight
Orders over 2kg and up to 30kg will be sent using a Fully Tracked Next Day Service using APC Overnight. Some smaller Roofing Kits that weigh up to 30kg in Total would be sent on this service. This includes Resins, Gelcoats and Topcoats which are classed as Hazardous and are decanted into 5kg Tins or Pales to comply with the Transportation of Hazardous Goods Act.
Pallet Network
All our larger orders by weight would usually be sent using the National Pallet Network. Non Hazardous Items can be sent using either the Pallet Network or APC Overnight.
All Hazardous goods over 30kg (which includes Roofing Kits over 30kg in total weight) are usually sent using the National Pallet Network on a Fully Trackable Next Day Delivery Service.
Click & Collect
All orders are eligible for Click & Collect. Pick up your items conveniently from our Cattedown Store, available Monday to Friday between 7:30 am and 4:30 pm (excluding Bank Holidays).
NB - Please note that our Direct Control of the Delivery Element extends to making sure we pick pack and dispatch all orders on time. As we have no Direct Control over the performance of any individual courier we would not be responsible for refunds due to the late arrival of any order.
We always work hard with customers to overcome any issues that arise so please call us if you do have any concerns with regard to tight delivery deadlines so that we can provide great advice if needed.
Please read our Returns policy laid out below.
Under the Consumer Contracts Regulations 2014 you are entitled to return goods within 14 days of delivery for a refund of the cost of the goods. The delivery costs and any packaging are not included in the refund. The returned goods should be in the original containers and unopened. It is the customers responsibility to pay for the cost of returning goods to our Business Premises.
Some of our products are made to order and as such once ordered are non refundable and non returnable. These include coloured gelcoats, topcoats and resins.
These Consumer Regulations do not apply to business purchases (B2B). However we will always help in any way and look to find a suitable and mutually acceptable solution should any issues arise through the order process.
It is the customers responsibility to understand the suitability of the product before its use. Technical and Safety Data Sheets are available for all products where applicable. These can be found on most product description pages or if not are available on request. If you are unsure please do not hesitate to contact us for expert advice and product suitability and application.
To organise a return please contact us on the following.
