CUSTOM 421 RED

£5.50£128.65 +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.

Need Assistance?

For more product information or have general question, please contact us.

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Product Details

RUST-PROOFING PRIMER IN OXIDE RED

PRODUCT COLOUR: OXIDE RED

Rustbuster Custom 421 serves as the ideal base for priming steel, aluminium, and GRP bodywork. It resists moisture absorption, preventing rust from forming within the primer, even when exposed for long periods. Unlike soft, porous easy-sand primers, Custom 421 provides durable protection, making it perfect for home auto restorers and garages without a controlled body shop environment.

After a light sanding with P320 abrasive, you can easily over-paint Custom 421 with either single-pack cellulose or two-pack finishes.

Product description 2 pack modified epoxy rust-proofing primer.
Pack description The 1.25L kit covers approximately 10m² and includes 800ml of Component A, 200ml of Component B, and 250ml of thinner.

The 2.5L kit covers approximately 20m² and includes 1.6L of Component A, 400ml of Component B, and 500ml of thinner.

The 6L kit covers approximately 50m² and includes 4L of Component A, 1L of Component B, and 1L of thinner.

Application temperature Can be applied to steel as low as 5c. 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

You can apply Custom 421 by brush or spray. A second coat or topcoat can be added after approximately 8 hours* without the need for abrasion between coats. If recoating or applying a topcoat after the first coat has fully cured (about 7 days), lightly sand the surface with P320 paper.

*At 20°C. In colder conditions, longer drying times may be necessary.

Spraying Minimum 1.8mm nozzle or an 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, 150 bar – 2176psi

Pot life

Pot life is the time between mixing the two components and when the paint becomes unusable. For Custom 421, the pot life is 2.5 hours at 20°C.

In colder temperatures, the pot life increases, allowing you more time to apply the mixed paint.

Shelf life It is advised to store the product upside down in a dry location at approximately 20°C. Under these conditions, the product will have a shelf life of up to 12 months.

Please avoid storing it at temperatures below 20°C, as it may impact the product’s performance.

Disposal Allow any excess mixed paint to cure in your mixing cup and be thrown away as dry waste.
Cleaning Clean the equipment with standard thinner or gun wash. Avoid using standard thinner to thin the paint, as it can adversely affect the curing process.
Safety Ensure usage in a well-ventilated area. When spraying or brushing in an enclosed space, wear a respirator mask. Refer to the MSDS (Material Safety Data Sheet) in our data sheet section for more information.

Always wear appropriate protective clothing, gloves, and eye protection.

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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