1.25 ltr Starter pack Epoxy Mastic inc thinner £29.95 ex VAT In Stock
1.25 Ltr Starter pack Kit c/w 1ltr Pre Paint Wipe, 3x Stirrer, 5x600ml Mixing Cups £37.50 ex VAT In Stock
2.25 ltr Chassis pack Epoxy Mastic inc thinner £54.99 ex VAT In Stock
2.25 ltr Chassis pack Kit c/w 1ltr Pre Paint Wipe, 3x Stirrer, 5x600ml Mixing Cups £62.50 ex VAT In Stock
6 ltr pack Epoxy Mastic inc thinner £99.50 ex VAT In Stock
6 ltr Kit c/w 1ltr Pre Paint Wipe, 3x Stirrer, 5x600ml Mixing Cups £107.00 ex VAT In Stock
Custom made colour 5 ltr inc thinner £99.50 ex VAT In Stock
EXTRA * Epoxy Thinner only 1 ltr £14.50 ex VAT In Stock
EXTRA * Epoxy Thinner only 250ml £4.95 ex VAT In Stock
EXTRA * Epoxy Thinner only 500ml £8.50 ex VAT In Stock

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Product Information


EM121 is our award-winning Epoxy Mastic paint, suitable for brushing and spraying. It is supplied as a two component pack, complete with thinner. Equal quantities of component A & B are supplied with each available pack size: the mix ratio is simply 1:1 by volume, plus thinner.

Starter and chassis packs are each supplied with 250ml of thinner. The 6 litre packs and 5 litre custom-colour packs are each supplied with 1 litre of thinner.

Packs are supplied with mixing instructions, including thinner quantities. All colours can be over painted with single or two pack products, but EM121 also works on its own as a primer-finisher with no need to be over-painted.

This product is typically very viscous (thick) and requires a correct mixing procedure and thinning with the supplied thinner. Please therefore follow the instructions to ensure best results, and see the links below for more assistance:

View Video: How to mix Epoxy Mastic EM121 

Rusty’s Tips: A practical guide on how to use this product 

Painting galvanised steel might take a little more preparation, Read More ClicK Here

Product Reviews

" I purchased some EM121 paint a while ago after reading numerous reviews, REALLY impressed with several factors, coverage, lack of mess, no runs, no brush bristles, how long the mixture was useable for and the quality of the results.."

5 Start Product ReviewMr A Pearson - May 2019


Product description

2 pack modified high build epoxy rust proofing paint.

Pack description

1.25ltr starter pack covers approx. 5m2. Includes 500ml component A, 500ml component Comp B & 250ml thinner

2.25ltr chassis pack covers approx. 10m2. Includes 1ltr component A, 1ltr component B & 250ml thinner.

6ltr pack covers approx. 25m2. Includes 2.5ltr component A, 2.5ltr component B & 1ltr thinner.

5ltr custom-made colour pack covers approx. 20 m2. Includes 2ltr component A, 2ltr component B & 1ltr thinner.

Application temperature

Can be applied to steel as low as 0c. The steel must be at least 3 degrees above the current dew point. (See our dew point calculator.)


Use only the epoxy thinner supplied, from 5 to 20% max.

Application & recoating

Brush or spray.

A second coat or topcoat can be applied any time after approx. 5 hours* with no need to abrade between coats. If recoating or topcoating once the first coat has fully cured (after approx. 7 days), lightly abrade first with P320 paper.

* At 20 degrees centigrade. Longer interval may be required in colder conditions.


Minimum 1.8mm nozzle or a HB (high build) primer set up. Test atomisation on a test panel first. Viscosity will vary, i.e. thicker in colder temperatures. Data correct at 20c.

Conventional Spray (Air) 3-4bar - 44-58psi

Airless Spray 18thou tip, 150bar - 2176psi

Pot life

Pot life is the time from mixing the two components together to the point at which the mixed paint is no longer useable. For EM121, you have 2.5 hours pot life once mixed at 20c – longer at colder temperatures.

Shelf life

We recommend storing upside down in a dry place at around 20c. In these conditions the product has a shelf life of 12 months.

Do not store below 20c as this can affect performance.


Allow any excess mixed paint to cure in your mixing cup and throw away as dry waste.


Clean up with standard thinner or gun wash. Do not thin the paint with standard thinner as this will affect the paint cure.


Use in a well-ventilated atmosphere. Use a respirator face mask when spraying or brushing in an enclosed space. Please see the MSDS (material safety data sheet) in our data sheet area.

Wear suitable protective clothing, gloves and eye protection.


Downloads and Media


How to EM121

Independent product review P.Cusick 2015


Matt Tompkins Practical Classics Morris Minor coated by us.

FORD RANGER Coated in Epoxy Mastic for Ford Motor Company for the RNLI Case history

RB EM121 Test Data Rv2.pdf

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Rustbuster Ltd
Welland House
Cradge Bank
South Lincolnshire
PE11 3AN

01775 761 222


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Rustbuster is a registered trade mark of Rustbuster Ltd, registered in the UK Trademark number 2211446 Class 02 & 37.
Any unlawful use of the Rustbuster name or logo or passing off will result in legal proceedings. Rustbuster Ltd UK registerered 3639350.