Rust.

[NinjaJunkie]

Took tank off and the bottom of the tank (outside - not inside) has patches of rust on it - inside of tank seems to be ok as fuel coming out of tap/carbs is clear and uncontaminated.

Can I stop the rust e.g. by sanding and respraying?

Thanks for any advice.

[Conrad_B]

Yeah. Take it right back to bare metal but watch you don’t go through the tank!

I’d brush on instead of spray if it’s not going to be seen… More durable finish and less work.
Use a decent anti rust primer, maybe fill with isopon if needed

Wire brush is good for getting rust off, even better if you have a circular one on a drill attachment…

[Alex_Gold]

Can’t remember which bike I had with this, but it was around the bottom of the tank. I just rubbed it down and hammerited a few layers over the top with a brush, then used cutting compound to blend it in a little. If it was further up the tank or a ‘mint’ bike I’d have maybe approached it differently.

[NinjaJunkie]

Thanks conrad b - yeah - sounds like the right course of action.

[NinjaJunkie]

Alex Gold (05/12/2011)

Can’t remember which bike I had with this, but it was around the bottom of the tank. I just rubbed it down and hammerited a few layers over the top with a brush, then used cutting compound to blend it in a little. If it was further up the tank or a ‘mint’ bike I’d have maybe approached it differently.

Yeah - hammerite is about right - it’s only my winter hack bike

[oldguy]

I can recommend Hammerite “Special Metals” primer. Sticks like the proverbial to an army blanket. (It’s a posh “red lead”. Don’t come that cheap, but worth it an you don’t need much to it so a “can is for life”. Oh. Halfords are a supplier.

After wire brushing, I’d also use a chemical rust killer to get into the pits that a wire brush just slides over. Then, as others suggest, hand brush on finish and finish off with a spray can if you want a near perfect finish.

[NinjaJunkie]

Thanks Oldguy - really good info - cheers.