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Organic Peroxide MEKP (Methyl Ethyl Ketone Peroxide) GRP (Glass-Reinforced Polymer, or Plastic) Catalyst Hardener is a high-quality, general-purpose catalyst designed to deliver reliable curing for a wide range of polyester resin systems. Commonly referred to as an Organic Peroxide Catalyst Hardener, this product is suitable for use with gelcoats, laminating resins, polyester lacquers, and bonding pastes. Its versatile performance makes it a trusted choice for both professional and industrial fibreglass applications.
This MEKP M-50 formulation presents as a clear, colourless liquid and contains a total active oxygen content of 8.8–9.0%. With a density of 1.180 g/cm³ and a viscosity of 24 mPa.s at 20°C, it provides consistent handling characteristics that support precision in resin curing processes. As with all MEKP initiators, it is essential to evaluate compatibility with the chosen resin system to achieve optimum results before committing to large-scale use.
Technical Specifications
Code: 27
Customer Reviews5.05 5.0/5 Based on 9 reviewsShow all reviews
Excellent serviceReviewed by Mike-b-1973 on 24 Dec 2025
Fast delivery and a quality product
First class resin & hardener from FSLReviewed by Onojracing on 08 Dec 2025
I've been using FSL for a while now and the products have always been excellent and very well priced. What is particularly impressive is the speed of delivery and comms - always excellent. Usually items delivered within 2 days, often the next day. Very happy and no reason to look elsewhere. Thanks 5 Stars
MEKPReviewed by Nick.harris47 on 07 Nov 2025
Works well
Not sexy but it worked.Reviewed by Robert.delaney1948 on 10 Oct 2025
It worked well enough. The only problem was that the printing of the mixing ratios was too small to read even with a powerful magnifying glass. It would be very useful to have a printed sheet of this supplied with each bottle.
Just what is says on the tin (Bottle)Reviewed by John on 10 Sep 2025
exactly what you would expect for a catalyst product
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.