Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Easy up hood windscreen supports

A healthy supply of salts for the electrolyte needed for the “battery” maybe coming from road salt spray drying onto the pillars, possibly contributing to the staining too.

Though you may not actually see it, Aluminium will oxidise with a thin coating within seconds after cleaning. That oxide actually protects the metal underneath and is not good at receiving paint. As an aside, when I worked in the electricity supply industry, in order to solder onto aluminium cable sheaths, a stick of abrasive solder needed to be continually rubbed onto the Ali, whilst applying heat, to cut through this oxide coating, whereupon a strong joint could be achieved. Similarly with painting aluminium, you need to break through that oxide coating before paint is applied. The only reliable way is to apply an etching primer and let it dry for a few hours before building up several paint coats on top.

Article updated with picture as complete and refitted.

https://www.thamesmog.co.uk/articles/technical/479-refurbishing-windscreen-supports

Well done, that is looking better than new.

We shall see how long it stays that way