I'm rather struggling with this so another question.

Caravan, alloy outer skin which is damaged and I need to repair it with
car body filler.

The problem is that car body filler is reputed to attack polystyrene
which is just behind the alloy skin and used for insulation. So I need
something to separate the two.

Your suggestions please.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk