Plating on plastic

Would you always start with Palladium then E-Ni no matter what the final coat is going to be?

Your question is a bit vague, Mr. Jean Claude, but rather than answering it yes or no, I would rephrase it and say that there are a number of ways of metallizing plastic but the one which is generally accepted as offering outstanding adhesion and reliability, sufficient to the demands of exterior automotive plating, is that one. It is possible to use electroless copper instead of EN if you need nickel-free plating.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

Another suggestion: Palladium or palladium-tin solutions are the most commonly used catalyst for electroless plating They are supplied by plating chemical suppliers along with complete instructions. However there are also non-precious metal catalysts for both electroless nickel and electroless copper, also available from plating suppliers with instructions. If you need more information, contact me, I will try to guide you to the solution to your problem.