The original question was to join aluminum to steel and what to do about the fasteners. Fasteners can be anything more noble than the materials you are joining. Stainless steel would work. Squirt sealant in the holes immediately before you insert the fasteners. Chromated sealant works best...
Try SermeTel 409 black or 1465 yellow. They are ceramic paints that will take your temps. Supplier is SermaTech. The coatings weren't listed on the website last time I looked. But you can get them.
It is possible that in rolling up the material, some moisture is trapped in the film and causes the cloudiness.
The slower drying of the emulsion into a film caused by high humidity or low temperature would make the cloudiness worse.
You might try a thinner film or a longer dry before...
