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How to seal galvanised steel post?

Hi all, I'm working on remediating rust off the below galvanised steel post/bases on my alfresco and entry eaves. They are 10 years old and are partially submerged into sand/dirt onto a concrete footing measure 500mm below my pavers. Have had a building inspector check the structural integrity of both posts and are fine but need some rust remediation to extend their life.

I have angle grinded the surface rust off these posts with flappy discs and wire wheel, cut off the nuts which I spent a week of spraying wd40 on everyday whilst using a socket to loosen from the rusted threads. I wasn't successful so carefully used a cutting wheel and cold chisel and hammer to crack the rusted nuts off the threads and have replaced the M10 nuts with new ones as below.

I have treated the rust at the base of the post/welds and at the footing level twice with rustbuster gel for 2 days and happy with the result.

Finally, a builder has told me to use epoxy resin to seal the post base and footing but cannot find any suitable 2 pack epoxy solution that fits my project. He suggested ramset epoxy paste 1210 but ramset no longer produce this product nor have a replacement product for this.

So, I was hoping someone here could help suggest an epoxy resin product to help seal the post or suggest another way of sealing the galvanised steel and making it watertight prior to priming the post and painting it. I have Dulux Metalshield All Purpose Primer and Dulux Weathershield Top Coat.

Thanks in advance.
- n.

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EricL

Hello @geon6

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

What an excellent surface restoration effort, the steel looks brand new. If the product you are referring to is the Dulux 500ML Metalshield All Surface Primer Grey, the compatible topcoat product is the Dulux 500ML Metalshield Epoxy Enamel Gloss Paint Vivid White which can be tinted to your preferred colour. My best advice is to make sure that the metal surface is dry and free of the rust converter gel before applying the primer. Since you already have the Metal Sheild Primer it would be practical to get a compatible epoxy paint to go with it rather than purchasing a whole new paint set.

Here is a handy step-by-step guide: How To Paint Metal

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

If you need further assistance, please let us know.

Eric

geon6

Hi @EricL,

Appreciate the thoughtful reply to my post.

My initial plan was to seal the base of the pole with epoxy resin where the rust was previously and then cover up the footing with the sand and pavers and the prime and paint the post from the level of the pavers up.

Are you suggesting to use MetalShield All Surface Primer and then MetalShield Epoxy Enamel Gloss Paint (can I tint to monument colour?) for the entire length of the post from the footing to the ceiling top?

Thanks. :)

MitchellMc

Hi @geon6,

Yes, that does sound like what Eric is suggesting. Priming and painting the area will help to prevent further corrosion. However, for the area below the ground, I'd be inclined to spray it with a few good coats of White Knight 300g Cold Gal Silver Rust Guard Spray Paint to restore the galvanised surface and then save the primer and paint for above the pavers.

You can have the Metalshield tinted to Monument.

Please let me know if you have any questions.

Mitchell

geon6

Hi all,

Update on project.

Have painted the metal base and footing with cold galvanised spray paint but not the White Knight brand (would be fine to use but looking for higher zinc purity in the paint) as recommended above. I have opted for Chemtools GalMax 93 Zinc Rich Cold Galvanising Spray Paint. I will let this cure for a few days. After curing, I'm going to waterproof seal with Gripset Betta Bitumen Membrane Waterproofing product (available at Bunnings), let that dry and cure for three weeks and then once cured put the sand and pavers back over the top and paint the reminder of the pole from pavers up.

As discussed with a Dulux Rep, I will prime the remainder of the post with Dulux Metalshield All Purpose Primer and finish with monument Dulux Weathershield Semi-Gloss top coat paint (also using for gutters, hence why I'm not opting to buy extra Dulux Metalshield Epoxy Enamel top coat paint).

Will post photos of process once finished.

Thanks
- n.

MitchellMc

Sounds good, @geon6. Weathershield is another great option.

You've done such a fantastic job so far, so it would be amazing if you could continue to take pictures as you go and upload them here. It would make a great resource to point other members to on how to properly go about restoring the surface of a post and prevent future deterioration.

Mitchell

geon6

Have done the cold galvanised spray and bitumen membrane seal.

For the cold galvanised spray paint:

Wiped and dusted the area off clean.
Shake the can for a minute until you hear the ball bearings move.
My spray application was from:
- Top of the tape all the way down to the base.
- The welds at the base of the pole to the concrete.
- Sprayed the thread and then apply new M10 nut and sprayed over that.
- Sprayed very outside edges between concrete and steel plate base.
Sprayed 2-3 coats (2 cans worth) to ensure every rust part was sealed.
Left 3-4 days (probably only need 1-2 days) to cure before applying bitumen membrane.

Bitumen membrane:

Only need 1L bucket (I bought the 4L but used very little of the product).
Used product straight out of the bucket (instruction does not say to stir membraned prior to applying so I didn't) with waterproofing brush (or your gloves if you can't be bothered clean a brush afterwards).
- No dilution required with water, use as is.
- Brushed the nuts first, then the base and then up the post.
- Be generous with the product as you want a thick membrane to seal the base with a waterproofing brush.
- Brush clean-up for this product on bucket says water clean up - not correct as water didn't get the bitumen component out of the brush so use mineral turpentine to clean and then wash out with soapy water.
Colour on application is bluish tinge and will dry to a black colour.
Takes an hour to tack/touch dry and then 2-4hrs before second coat can go on.
- Product recommends two coats for this project.
- Ensure when doing second coat not to paint the same direction otherwise the membrane will not stick properly.
- Curing takes 4-5 days before putting soil and sand back over and putting the pavers back over.

Will upload final part, once curing is done and prime/paint the upper part of the post.

EricL

Hello @geon6

Thank you very much for the update, I think you've pretty much applied maximum protection for that post.

We look forward to seeing the post fully painted.

Eric

Noyade

Afternoon @geon6

"They are 10 years old"

Just wanted to ask why the anchorage is buried so deep in the first place? Was the area built up? And what made you think after ten years to check?

Always curious.

Cheers.

geon6

@Noyade
No idea on the post design with the anchorage points - if you know the previous owner who I bought the property, I’d also like to know.

Prompted by building inspection when I brought the house a few months ago as a minor maintenance item to do these footings, only got around to sorting it now.

Noyade

OK. Thanks for that @geon6

When I first saw it I was thinking of welding rebar onto the nuts/bolts and extend upwards. Knock together Specrite form-work surrounding the area and then filling with concrete. Making sure the final troweling height is the bottom level of your pavers. Never need to dig and inspect again.

Anyway - cheers and carry on. 👍️

geon6

@Noyade
In choosing the process to repair these posts, I did consider what you proposed above and also a method of putting in a rebar into the post and filling the internal section of the post with quick set concrete upto ground level and being done with it. But in the long run the posts will have to be replaced anyway so I decided against making a form for the concrete to be cemented to ground height as you have kindly proposed as I would have to knock out the concrete to get to the base and remove everything to start from scratch in replacing the post.

Appreciate the advice you have given though, much appreciated.👍️

geon6

Hi all, final post here.

I did do a third coat of bitumen membrane to ensure the junction between the concrete pad and the galvanised steel footing was completely sealed and let that cure for 5 days before covering up with sand and relaying the pavers. This technique ensures any water ingress through the pavers runs down the membrane and away from the concrete pad into the adjacent sand.

Before painting the post - prep it, you will get a better looking result:

Remove any excess bitumen membrane above ground - use a Stanley knife and a small square to mark at paver/ground level to remove excess. See below.

Double-check any remaining rust spots on the post and treat again with rust converter. Wipe off any white areas after treatment.
Any defects/indents on the galvanised steel post:
- Any high spots/surface rust, missed paint - sand back with orbital sander/40 grit flappy disc on angle grinder and any remaining surface rust treat again with rust converter being careful not to cover the good existing galvanised steel surface and only the rust site.
- Indents on galvanised post - use special metal builder's bog for metal such as Turbo Builder's Bog to patch the pole and sand flush after its dried (I didn't do this step but should have after reading another members post on this forum).
Clean post with mineral turpentine with microfibre cloth.

Painting the post:

Waited for a cool day between 20-30 degrees.
Checked post temperature with laser thermometer.
Added Floetrol paint conditioner to help maintain wet edge.
Used a small straight cutting brush and 10mm nap microfibre roller apply paint.
- Foam roller also would produce smoother looking coat.
Primed bare post with one 1 coat of Dulux Metalshield RFU Etch Primer Grey.
Painted 3 top coats of Dulux Weathershield Semi-Gloss, Monument/Extra Bright.

Do note that the quality of these galvanised posts I had to work with were really poor due to the way it was manufactured and being neglected by the previous owners for so long without treatment.

In my case after extensive rust treatment, underground waterproofing, metalwork preparation and potentially another top coat or two of paint I think, I've achieved a good finish here given the quality of post to work with.

Hope this helps people intending on remediating and restoring a galvanised post. Thanks to everyone for their input and guidance on getting me through this project.

If anyone knows how much this project would have cost me if I engaged a builder to perform this project I would appreciated hearing it - I spent a week trying to engage with 3 different builders who either we not contactable or was not interested (wouldn't quote me) in this small job.

Many thanks again. 👍️

JacobZ

Hi @geon6,

You've managed to achieve an exceptionally good finish which I am positive will last a very long time.

Thank you for documenting the process in such detail for our members to use as a resource. I am positive your efforts will help others greatly in the future.

Jacob

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