The Amazing Spider-Man #348

Alternative Name: Amazing Spider-Man (1963 1st Series)

In Avengers 329 both the Sandman and Spider-Man became reserve members of Earth's Mightiest Heroes! And while the web-slinger isn't overly concerned about gaining the acceptance of his new teammates; the Sandman sure is! So when William Baker (aka Flint Marko) gets a tip about a train hijacking at the Brooklyn railyards; he quickly calls the Avengers! And as expected Cap, Thor, and company (along with the web-slinger) make short work of the heavily-armed saboteurs! But for the Sandman the victory is bittersweet. His days with the Avengers may be over.