A question about steel baths and repairing them

[ElCI]

My bath has 2 chips out of the enamel, one of these is quite a large chip (about 6 or 7mm diameter), both caused by my kids throwing things into the bath! I posted an old picture of 1 of them, it's probably slightly worse now.

Below the chips is a black substance. I have been told before that my bath is a steel tub, I assume this means steel base with enamel lining, I'm not sure if there's a way I can confirm this?

My question is, if the bath is steel then will these chips cause any issues? The 1st one happened a few years ago and I have been repairing it by sealing it up ( using geocel the works), I have done this with the newer chip also although this one is significantly larger. Is there a better way of repairing this as I have found that after a few months the sealant gets rubbed off (by people having baths every day)

Thanks

 

[Dangee]

Bath doctors can repair virtually invisibly but personally, dry it fully touch it in with enamel paint (small nail varnish size) it gives you a little brush , just “ blob” it, tiny amount needed.

 

[ElCI]

Bath doctors can repair virtually invisibly but personally, dry it fully touch it in with enamel paint (small nail varnish size) it gives you a little brush , just “ blob” it, tiny amount needed.

Thanks, does that also makeeit watertight?