Mike Grella had two chances in the first-half, with a seventh-minute shot going wide and a 30th-minute effort turned wide by Bray keeper Brian Kane.
Mark Duffy also fired an effort wide, while Josh Waler headed an effort straight at Kane.
Barcham, who replaced Duffy at the break, grabbed the only goal of the game after 57 minutes when he found a bottom corner of the net after surging into the area.
Matt Godden hit a post for the Iron, while midfielder Michael Collins made a surprise appearance off the bench as he seeks to return after a string of injury problems.
Niall Canavan (knee) and Damien Mozika (ankle) sat out the game, with Mozika not expected to feature until the Iron return to the United Kingdom.
Several trialists featured in the game. The defender Tom Newey, who was released by Rotherham this summer, started the match while Hull City midfielder Matty Mainwaring has also been confirmed as part of the touring squad.
Around 60 Iron fans travelled to Ireland for the game.