Rust on hand rail at water line

[a_t]

Hi guys,

My hand rail was installed in April of 2022, so it's about 3 years old. I just noticed that it started to rust, but only at the water line. Do you know if it has to do with that white stuff on the rail? I don't know what it is - calcium, salt?… I'm sure that with some effort I can take the rust off, but need help figuring out what's causing it and how to prevent it from reoccurring.

Thanks!

 

[PoolStored]

This is very common.

Your pool water is brackish and so chloride induced crevice corrosion and pitting will always be a failure mode for the steel. Anytime you can pull the ladder and rinse it off with fresh water, the better it will be. Saltwater can splash all over the ladder, dry and leave behind an enriched chloride film. Add to that a potent oxidizer (chlorine) and you have a recipe for corrosion. Chloride ions are very aggressive toward metals, and when a film forms, it can break down the protective oxide layers on metals, even SS. What you are seeing is pitting corrosion as a result. It can also lead to stress corrosion cracking.

Corrosion happens at the waterline because oxygen levels are lower there, breaking down the protective layer on the metal. Plus, splashing and evaporation concentrate chlorides right at the surface, making it the worst spot for pitting and rust. It's called the "splash zone" effect.

Once corrosion of steel starts, it doesn't stop. It will only get worse, not better. So, at some point you need to pull the handrail, and clean off the corrosion. You'll probably need to use something like Naval Jelly to restore the metal surface and add back a passivating layer and sealer.

After the naval jelly, I'd use Teknikem CitriSurf 77 Plus for passivating, and for a sealer, I'd look at Everbrite. There are better solutions, but not for DIY.

I have the same issue with my ladder, and I'm going to do the same treatment.