Acf 50 And Foam

[hallrob1]

This is in relation to my XJR but this is still the best forum for useful information and a lack of hysterical replies so I thought I'd start here.

 

I've discovered that the aforementioned XJR has some hidden rust issues on the frame - mainly the rear subframe. The reason is that there are soft foam blocks on the inside of the tail panel that are cleverly designed to hold water against the steel frame and this bike has spent most of it's life on the coast in Torquay.

 

As a temporary fix I've covered the area with ACF50 and my question is whether this would attack the foam?

 

I'm not sure I'm up for a engine removal and powder coat of the frame so this could be a longer term temporary fix.