Hetfield and Ulrich fired Mustaine on the morning of April 11 after a gig in New York, because of his drug and alcohol problems, overly aggressive behavior, and clashes with bandmates. On Whitaker's recommendation, Metallica recruited Kirk Hammett, who played in Exodus and was a one-time apprentice of Joe Satriani. Hammett learned the songs on his flight to New York, and started recording the album with Metallica barely a month later. Metallica met producer Paul Curcio at Music America studios in Rochester, and recorded the album in two weeks. Unable to afford a hotel during the recording sessions, the band members stayed over in people's houses in Rochester and at the Music Factory in Jamaica, Queens, where Anthrax held rehearsals. Curcio had set the studio equipment as if he were recording an ordinary rock band. He thought the initial tapes sounded very distorted, and tried to compensate by turning down the knobs. Metallica resented Curcio's involvement, because he seemed uninterested, and had little impact on the sound. Although Zazula wanted Hammett to replicate Mustaine's solos, Hammett's guitar solos on the album were partially based on Mustaine's original solos, with the first four bars of most solos written by Mustaine before his departure. Despite their differences, Mustaine's contributions to the early years of Metallica were still acknowledged, and he received four co-writing credits on "Kill 'Em All". Zazula was not pleased with the initial mix because he thought that the drums were too loud, and the guitars were too low in the mix. The remix was done by sound engineer Chris Bubacz, according to Zazula's instructions. The final cost for the record rounded to an estimated $15,000, which nearly caused Zazula to go bankrupt. "This was mortgage money I'm spending, not something I've got put by I'm going to invest," he said later. Zazula had a hard time finding a distributor for the record, but he eventually convinced Relativity Records to distribute the album in the US and Canada, and Music for Nations in Europe.