RUST PROOFING PRIMER IN GREY
PRODUCT COLOUR: GREY
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 throw it 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. |
