Rust sealer for enameled bath

My bath has developed a rust spot right in the middle. My father told me that you can get some kind of sealer to prevent the enamel from further cracking.

I have had a look around but found nothing. Any ideas what he is talking about? How do I say it in Chinese?

Thanks,

L.

I’d take a picture of the tub problem and show it to the nearest paint shop.
Chances are that if they don’t have what you need, they will direct you to the store that does.
I’m sorry I don’t have the information that will help you. We have used a tub enamel in the States. It came in a very small bottle - a bit larger than nail polish bottle size. And it had a small brush attached to the cap, also similar to nail polish bottles. Another possibility, for a larger area, is to use a metal paint. The brand name paint Rust-oleum would be good. I’ve used it on metal outdoor chairs.

Good idea about taking a photo. I really want to prevent it from spreading any further. Cheers. L.