Tank painting thoughts

[andy120t]

I'm slowly getting round to painting a tank for an old GSXR. It'll just be a shed/ rattle can job so nothing fancy, but I want to make as good a job as I can.

It's previously been stripped to bare metal then left outside which means it has a lot of little rust dots on it. I rubbed it down to flat and sprayed a bit of black paint on it - the dots reappeared but haven't got any worse after 14 years.

Question is - any thought on an appropriate undercoat/ treatment I could use to stop these reappearing when I spray it?
Thx!

[ozzybud]

Sand to bare metal again, trying to remove as much of the surface rust as possible. Then treat with a conversion coating  that neutralizes the rust. Por-15 or Rust Mort. Then spray with a good epoxy primer.

[andy120t]

Thanks . I've found that they also offer a spray version in white which would be a good base for my blue / white gsxr paint! Recommendation is to use it over their base layer/ treatment so I'm going to give that a go when it's a little warmer.

[McCabe-Thiele (Ted)]

When I spent some time as a sprayers assistant in the 1970s we used a special fluid to stop flash rusting and seal up areas where lead filler had been used.
With the passage of time I've forgotten the name I think it was a Phosphoric Acid based product.

[Matt_Harrington]

There used to be a product called Fertan that was pretty good at rust conversion. I think you can still buy it. Also Jenolite in the past as well. Whatever rust converter you use, use a decent epoxy primer on top. I have recently used some new primer and it is really good - I can let you know what it is if you want. Your best bet is to find a local refinishing centre and ask them to recommend something. Products get better all the time.