>>7982537>Newfag here>I plan to paint its right arm using metallic silver spray paintFirst off, the chances of you getting the level of finish in your pic related with a spray can and no experience is about 0.
Forget the metallic spray, go get a good black gloss and some electroplating powder and you will actually get a gorgeous metallic finish as long as your black gloss coat is perfect like pic related (which you can achieve either by good spraying technique or by polishing).