I wouldn't introduce any adhesive in the CC unless I was sure it would be inert.*Can use adhesive heat shield material(like in cars) inside the smoker?
*I want to use a rope seal for the door & want to know the best way to adhere it to the door, is there a high temp silicone or similar I can use?
*Can I use galvanized down pipe as the flu/chimney, if not then what should I use?
*I know they make stills out of copper, can I use it inside a smoker? I'm thinking of using chrome plated copper pipe screwed into the side for the rack supports
RTV high temp silicone is used for the rope gasket.
Galvanized should be OK for that but I'd make sure nothing can drip off from it onto the food.
Copper is fine as long as there's no contact with food. Be careful with anything plated that it doesn't flake.
In addition: Be careful of any kind of foam insulation. It may not be suitable for heat.