How to protect steel post showing early sign of rust?

[lukelee]

The two years old steel post is showing early sign of rust. Picture is below. It is under the decking, touch the ground, some grass around, it was wet after rain.

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I went to bunnings last week, tried to find some products to fix the rust. My understanding is to

1.Clean the rust with steel brush. 2.Apply rust converter. 3.Apply primer. 4.Apply Topcoat.

There are so many products, I was confused. There are three Rust converters.

1. Dy-Mark MetalPro Rust Converter
2. White Knight Rust Guard Rust Converter

3. Bondall Ranex Rustbuster Rust Converter

Which one is the best? The staff told me they are three different chemicals?

Then the Primer, there are

1. White Knight Rust Guard Metal Primer Paint

2. White Knight Rust Guard Cold Gal Primer Paint

3. Dulux Metalshield Rust Defence Primer

4. Dulux Precision All Metal Primer

5. Dy-Mark MetalPro Zinc Gal Primer

6. Dy-Mark MetalPro Silver Zinc Metal Paint 2 in 1

I also see some Etch , or Epoxy primer, which one is better?

And the last: Topcoat, we have

1. White Knight Cold Gal Silver Rust Guard Primer Paint

2. Dy-Mark Aluminium MetalPro Quick Dry

Do I need topcoat at all? The post is under the deck, it doesn't need to look nice. Can I apply two layer of primer instead of one layer of primer and one layer of topcoat?

Is Dy-Mark MetalPro Silver Zinc Metal Paint 2 in 1 better than Primer + Topcoat?

Can I mix the brands? Or better stick with one brand? White Knite seems more expensive than Dy-Mark, is White Knight a better brand?

Many thanks.

[EricL]

Hello @lukelee 

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about protecting your steel post. 

It's best not to mix and match as these products work well when working with the same brand. For example, since you are not going to need a great deal of paint, I suggest using the White Knight 0.125L Rust Guard Rust Converter in combination with the White Knight Rust Guard 300g Grey SLS Etch Primer Spray Paint. For the topcoat I suggest using the White Knight 300g Cold Gal Silver Rust Guard Spray Paint - Bunnings Australia.

Using two coats of primer is not enough to protect the surface a topcoat must be applied. Now between the three brands only the White Knight is offering it in a smaller quantity. White knight is a trusted brand and works well to preserve steel.  

My best advice is to make sure that the affected area is clean and make sure to cover any exposed area with drop sheets and masking tape to prevent over spray.

Please make sure to wear personal protection such as gloves, goggles and a mask when working on your project.

Here is a handy step-by-step guide: How to paint metal

If you need further assistance, please let us know.

Eric

[lukelee]

Thank you Eric.

My deck is 250m2, there are many posts, I need many cans of these spray.

Do you recommend Spray or hand brush? I don't need to worry about the appearance.

[JacobZ]

Hi @lukelee,

If you are doing a huge amount of posts, then brushing or rolling the products on is going to be much more cost effective.

I'd suggest grabbing the White Knight 1L Rust Guard Rust Converter, White Knight Rust Guard Medium Grey Metal Primer Paint and White Knight Cold Gal Silver Rust Guard Primer Paint, alongside a Paint Partner Mini Roller Kit and Paint Partner 50mm / 75mm 2 Piece Paint Brush Set.

Let me know if you have any further questions.

Jacob

[lukelee]

Thank you, Jacob.

Why do you choose White Knight Rust Guard Medium Grey Metal Primer Paint, not White Knight Rust Guard Grey SLS Etch Primer Spray Paint, and White Knight Rust Guard Cold Gal Primer Paint?

[EricL]

Hello @lukelee 

The primers work pretty much in the same manner, but some of them have extra properties that allow them to be used for specific surfaces. 

• White Knight Rust Guard Medium Grey Metal Primer Paint - It is ideal for priming steel, wrought iron and structural steel and is suitable for use on fences, roofs, doors, gutters, pipes, windows, railings and gates.
   
• White Knight 1L Rust Guard Quick Dry SLS Etch Primer Paint - It is an etching primer with a superior locking system for maximum rust protection. Ideal for priming aluminium, galvanised iron zincalume, chrome, brass and copper objects to protect from corrosion. It is suitable for use on fences, roofs, doors, gutters, pipes, windows, railings and gates.
   
• White Knight Rust Guard Cold Gal Primer Paint - It is a zinc rich and heavy-duty primer that forms a self-sacrificing protective barrier against corrosion. Ideal for welds and repairing damaged galvanised iron, White Knight Rust Guard Cold Gal protects ferrous metals (e.g steel and wrought iron) in highly corrosive environments such as coastal areas.

The White Knight Grey Metal Primer is perfectly ok to use on your steel post.

If you need further assistance, please let us know.

Eric