Oil Boiler - Corrosion

[Onoff]

So back around March 2015 I posted up on eBuild about doing a few bits to keep my 1998 Warmflow oil boiler going. 

 

I fitted a new burner nozzle, a couple of new baffles and re-made the 2 piece, rivetted together lid.

 

2015

 

 

 

 

I didn't treat the steel other than rubbing it down and spraying with high temperature black paint. I also replaced the burnt thru insulation mat under the lid.

 

Fast forward to now,  Apr 2018 and I decided to take the new lid off to give it a quick respray as SWMBO had placed a rusty garden ornament on to and scuffed it all.

 

Underneath was shocking, the lid has a 1mm tin cover and a heavier 2mm thick formed tray. The tray section was as rusty as! It was WORSE than in this picture which is after I wire brushed it:

 

2018

 

 

The rust from the lid caked this insulation but I forgot to take a photo before I vacuumed it:

 

 

Underside the lid insulation is a bit black:

 

 

For now it just got the worst off the rust brushed /scraped off and that atop the insulation hoovered up. Gave the inside a quick spray again:

 

 

The original lid lasted far longer.

 

What causes this rust, condensation?

 

Cheers

[dpmiller]

Yup. Was the lid well clamped down?

[Onoff]

16 minutes ago, dpmiller said:

Yup. Was the lid well clamped down?

 

Well I thought so, two wing nuts.