Winter can be hard on exposed steel. Rain, moisture, salt and condensation can leave trailers, gates, outdoor furniture, machinery and other steel surfaces showing signs of rust by the time spring arrives.
The good news is that surface rust does not necessarily mean the steel needs replacing. With the right preparation and rust treatment, many rusty surfaces can be restored and protected before corrosion becomes a bigger problem.
The key is knowing how much rust needs to be removed, which abrasive to use and when a Rust Converter such as Rust Con can help.
Why You Should Not Just Paint Over Rust
Painting directly over loose rust might improve the appearance temporarily, but it does not provide a sound foundation for the new coating.
Loose rust, scale, flaking paint, dirt and contamination can prevent paint from bonding properly. Moisture can also remain trapped beneath poorly prepared coatings, allowing corrosion to continue.
Good preparation removes unstable material and creates a surface that can be properly treated and coated.
Start By Assessing The Rust
Before reaching for the grinder, take a closer look at the condition of the steel.
Light surface rust may only require relatively gentle preparation. Heavier corrosion with loose scale and failing paint will need more work, while badly corroded steel should be inspected to determine whether it is still structurally sound.
The objective is not always to grind every surface back to perfectly bright steel. What matters is removing loose and unstable material and preparing the remaining surface for the next stage.
Which Abrasive Should You Use?
Different abrasives perform different jobs. Choosing the right one can save time and prevent unnecessary removal of sound steel.
Wire Brushes
A Hand Wire Brush is useful for small repairs, corners, edges and areas that are difficult to reach with a power tool.
They are inexpensive and give you plenty of control, although they can become slow when working on larger areas.
Wire Wheels And Cup Brushes
Wire Wheels and Wire Cup Brushes fitted to a suitable power tool make faster work of loose rust, scale and failing coatings.
Unlike a grinding disc, the wire works across the surface and around contours without aggressively removing large amounts of sound steel.
They are particularly useful on gates, trailers, machinery, fabricated steel and irregular shapes.
Abrasive Flap Discs
When more material needs to be removed, A Flap Disc can be a better choice.
Flap discs use overlapping abrasive sections to cut into the surface. They are useful for removing heavier corrosion, cleaning up rough areas and feathering the edges between existing paint and exposed steel.
Because they remove steel as well as rust, avoid applying unnecessary pressure or staying in one place for too long.
The grit you choose also matters. A coarser abrasive removes material faster, while finer grits provide greater control and leave a smoother surface.
Abrasive Fibre Discs
Conventional Abrasive and Grinding Fibre Discs can be useful where more aggressive removal is required, particularly with heavy coatings or stubborn corrosion.
As with flap discs, the aim is to remove the problem without unnecessarily grinding away sound material.
What About Heavy Rust And Scale?
For larger areas or heavily corroded surfaces, conventional grinding and wire brushing can become time consuming.
For serious corrosion or large areas, professional sand blasting may be the most efficient way to properly prepare the steel.
The important point is to match the preparation method to the job. A small patch of surface rust does not require an industrial approach, while attacking a heavily scaled surface with a hand wire brush can turn a straightforward repair into an all day project.
Do You Need To Remove Every Trace Of Rust?
Not necessarily.
Loose rust, scale and failing coatings should be removed, but remaining ferrous rust can be treated with a suitable rust converter once the surface has been properly prepared.
This is where Rust Con comes in.
Rust Con is a New Zealand made rust treatment, rather than simply covering rust, it reacts with ferrous rust and converts it to magnetite, creating a stable, sealed surface ready for painting.
This can save considerable preparation time where removing every trace of corrosion back to bright steel would otherwise be difficult.
Preparing Steel For Rust Con
Good preparation is still important when using a rust converter.
Remove loose and flaking rust, scale and failing paint using the most appropriate abrasive for the job. The surface should also be clean and free from contaminants that could interfere with the treatment.
Rust Con should not be viewed as a substitute for preparation. It works as part of the process after unstable corrosion has been removed.
Always follow the product directions regarding surface preparation, application and drying before applying subsequent coatings.
What Can Rust Con Be Used On?
Rust Con is suitable for a wide range of ferrous metal maintenance and restoration jobs, including:
Trailers
Gates and fences
Steelwork
Machinery and Vehicle components
Roofing, pipes and railings
Steel doors and window frames
Once treated, the surface can be coated with suitable water based or solvent based paints.
Protecting The Steel After Rust Treatment
Removing and treating rust is only part of the job. The surface also needs protection from the conditions that caused the corrosion in the first place.
Choose a suitable coating system for the environment and make sure the Rust Con treatment has been completed according to the application instructions before painting.
Pay particular attention to edges, joints, welds and areas where water can collect. These are often the first places corrosion returns when a coating begins to deteriorate.
Regular inspection can also help catch small areas of rust before they become larger repairs.
What If Rust Has Left A Hole Or Damaged Seam?
Sometimes corrosion has progressed beyond surface rust and leaves small holes, damaged seams or areas where water can enter.
For suitable non structural repairs, Flex Flashing Tape provides another useful option. The flexible butyl sealing tape can be used to bridge and seal small holes, seams and joints, creating a waterproof repair that can also be painted to blend with the surrounding surface.
It can be particularly useful for repairs to roofs, sheds, shipping containers, flashings and other areas where sealing against water is important.
Available in 2 widths:
As with any repair, remove loose corrosion and prepare the surrounding surface before applying the tape. Where corrosion has significantly weakened a structural component, the damaged steel should be properly assessed rather than simply covered.
Do The Preparation Once And Do It Properly
Rust repair is one of those jobs where preparation makes the difference.
A quick coat of paint over a rusty surface may look better initially, but removing loose corrosion, choosing the right abrasive and properly treating the remaining rust gives the new coating a much better foundation.
Whether the job calls for a wire brush, wire wheel, flap disc or more serious mechanical preparation, match the abrasive to the condition of the steel rather than using the most aggressive option available.
For remaining rust, Rust Con provides a practical way to convert and stabilise the surface before painting. Where corrosion has resulted in small holes or damaged seams, Flex Flashing Tape can provide a paintable sealing solution for suitable repairs.
Explore Millin's range of Rust Con, abrasives, flashing tapes and surface preparation products and get your steel ready for its next coat.