£45.00£179.99 +vat @ 20%

Free Delivery

On orders over £90.00+VAT, up to 20Kg.

Delivery Details

Free Shipping UK mainland (Most Destinations)

Free Standard Shipping (not next day) on orders worth £90 +vat or more, which also weigh 20kg or less to non-remote, UK mainland locations.
Free shipping is shown at checkout on valid orders

Rustbuster intend to ship all orders within 24 hour via economy carriage shipping, this can be next day but could be up to 2 days.

Next day delivery DOES NOT include Saturday or Sunday. Any next day orders placed on a Friday will be received on Monday, as Saturday is not included as a working day.

Rustbuster Standard Economy shipping is £8.50+vat for up to 20kg.

Remote areas/Scottish Highlands and non-UK Mainland areas may be subject to additional charges and a longer delivery time. This is determined by our couriers not Rustbuster.

Northern Ireland and Ireland
Up to 20kg of Hazardous goods can be sent, this currently costs £25.00+vat, we do however have a Stockist in Ireland and this may workout a more cost effective way to purchase.

International shipping
International shipping prices vary, please contact Rustbuster if your country is not listed at Checkout.

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Product Details


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.)
Thinning 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.

Spraying 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.

Disposal Allow any excess mixed paint to cure in your mixing cup and throw away as dry waste.
Cleaning Clean up with standard thinner or gun wash. Do not thin the paint with standard thinner as this will affect the paint cure.
Safety 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.

FAQ’s How many coats are recommended? We would always recommend 2 coats, this will increase the coatings thickness offering better protection and removing the chance of missed areas (holidays).

Can I paint over a rusty surface? Yes, EM121 is non-porous so will 100% seal the rusty surface, we would recommend removing all loose material from the surface before painting. 

Does EM121 come in colours? Yes, 14 colours available from stock and custom colours available (minimum packsize 5ltr kit).

How long beofere I can overcoat? 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.

Can I paint over EM121 with a cellulose topcoat? Yes, EM121 will accept pretty much every type of topcoat, if I doubt we would recommend testing a small area and watching for any reaction before performing an adhesion test if required.

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


Rusty's Top Tips from Rustbuster

Hello Corrosioneers!

RUSTY here, for handy tips and guides on how to get the best from our Rust busting products, check out my helpful guides at Rusty’s Tops Tips

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