Water tank paint issues

[TheBiscuits]

40 minutes ago, David Mack said:

If unrinsed fertan is that bad for the bond with subsequent layers, then just scraping the bitumen off might not be that difficult.

 

That would certainly be the first thing I'd try.

 

Of course any areas that don't want to come off with scraping or wire brush may be assumed to be well stuck, so can probably be left and overpainted.

 

The photo shows rusty bits where there is pitting, so those areas need concentrating on but a clean, fertan, wait 24 hours, rinse, dry, repaint should do the job acceptably.