How to treat rust in bathroom steel door?

grprojects

I have rust in a steel bathroom door frame that is very close to the shower recess. The bath is still used on occassions but shower has not been used much for a long time. Just recently the grout along the door frame showed signs of cracking and it was found that the cold water tap had a very slow water leak from around the fibre washer. This has been repaired. However the moisture reached the door frame causing it to rust.

I am looking for a recommended method to inhibit the rust and prevent further deteriation. I have looked at a number of methods and considered using Flood Penetrol. I have checked the soundnees of the door frame and it appears to be still quite sound. I am also interested to know if there is a reliable method to try and treat/prevent rust on the interiror of the door

frame. I removed the scale as much as possble in the tight space between the frame and the tiles. See attached image.

MitchellMc

Welcome to the Bunnings Workshop community @grprojects. It's fantastic to have you join us and many thanks for your question on fixing rust.

The key thing to understand is that rust can only continue progressing in the presence of moisture. Since you’ve now fixed the leaking tap and stopped the water source, you’ve already dealt with the main cause. From here, it’s really about removing what you can and sealing what remains.

First, mechanically remove as much rust as possible. In tight gaps between the frame and tiles, a small wire brush, abrasive paper, or even a rotary tool with a wire attachment can help. Don’t worry if you can’t get it back to shiny bare metal everywhere, the goal is to remove all loose scale and flaking material.

Once cleaned, apply a rust converter to any remaining rust. This chemically stabilises the corrosion and turns it into a paintable surface. After that has cured, apply a suitable metal primer, followed by a couple of coats of a good quality enamel topcoat to seal it. The sealing step is what prevents moisture from getting back in.

Regarding products like The Flood Company 300g Penetrol Spraycan, that's certainly an option, and might allow you to get it in the cavity where it's needed better than some of the paintable options. However, if you are able to get in there with a craft paintbrush, I would go with the liquid versions.

As for rust spreading to the other side or inside the frame: time will tell. If the internal cavity stays dry, there’s a good chance it won’t progress significantly. Rust needs ongoing moisture to keep developing. If it does show up later, you’d treat it the same way, remove loose material, convert, prime, and paint.

Please let me know if you have any questions.

Mitchell