How to prevent rust at base of a steel post

[dinga]

G'day

My carport roof has 6 supports - 4 concrete posts at the corners and 2 steel posts (encased in concrete) halfway down two sides. My problem is with only one of these steel posts. It is exposed to water run-off and as a result is rusting at the base (exacerbated no doubt by being close to the beach). A couple of photos are attached.

I'm concerned about arresting the current rusting, and protecting the post from rust in the future.

Am thinking about:

* firstly removing the rust, and treating the metal with rust converter

* applying a thick protective covering of water-proof cement to the base (have successfully used this stuff to seal an above ground, brick fish pond.

Will this work? Welcome better solutions!

Tks

[stoneyboy]

Not sure of the availability of this product here but it's as good as they get.

There must be alternatives if not.

[manfredtillmann]

try this:

clean off all rust as good as you can and apply something similar to cold galvanizing paint (like shown in the above post, but anything rustpreventing will do).

wait until dry and do again. when all dry and good, wrap some two or three layers of thick hessian or other absorbent natural material around you post base to protrude past what you will do next.

buy a cheap bucket of suitable size, cut out its floor and split the bucket lengthwise. use it as formwork, you will need some strong sticky tape to put it back together once you got it around your post. make a reasonably stiff sand & cement mix, fill your bucket around the post, pad the sides of the bucket gently from time to time while you are filling it up.

before the mix goes off, remove your bucket and finish the outside of the new 'dome' to your liking, making sure the top tapers away from the post to the outside all around.

next day trim the hessian and with a small oil pump or a syringe soak the hessian repeatedly with clean gearbox oil (you can add something like WD40 for lower viscosity). keep the oil up to it regularly as in monthly, it will never rust again and it will look lots better than what you have there now.

[mike324]

Not sure of the availability of this product here but it's as good as they get.

ImageUploadedByThaivisa Connect1460438500.377388.jpg

There must be alternatives if not.

there are anti-rust paint for metal, don't remember the brand, but the color was orange...should be easy to find at any local hardware store.

[CGW]

Good welding and correct application of a decent quality paint would have prevented this problem, sure you needed to know that!

The average builders welding skills are atrocious, add to that poor quality steel and you have a recipe for what you have, clean it of as best you can, if the steel has rusted all the way through I would weld "stiffeners" on top of the existing steel, after clean off the welds, which means clean off all the slag and apply a coat of good paint. Paints have come a long way in the past ten years a good "two pack" paint will last for many years, here they use red oxide primer only, we used to use it in the offshore industry 40 years ago it's just about useless unless it has a good topcoat to seal it as it is porous.

[Gonsalviz]

Thailand has Red Oxide Primer. Mix it well, clean the rust off mostly to bare metal and paint it on. It is tough and will stop the rust. Similar to 'Rustoleum' in the States.

[eyecatcher]

Thailand has Red Oxide Primer. Mix it well, clean the rust off mostly to bare metal and paint it on. It is tough and will stop the rust. Similar to 'Rustoleum' in the States.

If I can add; do NOT thin this primer down at all and apply at least two coats....then you have a chance.

as the above poster mentioned, it is quite useless and use here as lip gloss to make a show.

Platong is the better of the crap stuff.

[dinga]

Thanks for all the suggestions - here's what I've done:

1. Chipped away all the rust (still appears structurally sound) and applied rust converter

2. Covered both the base plate and the steel post with a protective epoxy seal approx 1.5cm in depth (as a template, used the top of a plastic container from the 20 Baht shop.....)

3. Applied 2 coats of unthinned red oxide primer over that part of the steel post painted with the rust converter

4. 2 coats of enamel paint applied over both the primer, and the epoxy seal

Fingers crossed - couple of photos attached

[BobTH]

dinga it looks like you did a very nice job. I worked in the corrosion prevention field for 37 years on pipelines both offshore and onshore and dealt with splash zones similar to what you have there. I and am now retired here in Bangkok. I have been following your thread from the start and wanted to comment earlier that I felt you should go with a two part epoxy coating but just kept quiet . Good job and good decision on your part to use it, I feel you will get several years service out of the repair.

[dinga]

dinga it looks like you did a very nice job. I worked in the corrosion prevention field for 37 years on pipelines both offshore and onshore and dealt with splash zones similar to what you have there. I and am now retired here in Bangkok. I have been following your thread from the start and wanted to comment earlier that I felt you should go with a two part epoxy coating but just kept quiet . Good job and good decision on your part to use it, I feel you will get several years service out of the repair.

Tks BobTH - hope more than 'several' (area doesn't get wet that often, especially now that the dog bathing area has been moved!)