Try using $addtok to add your tokens with the ASCII Character you want between the respective tokens. EX:

on !*:join:#: {
  if ($comchan($nick,0) > 1) {
    var %output, %start 1
    while ($comchan($nick,1)) { %output = $addtok(%output,$v1,32) | inc %start }
    msg $chan %output
  }
}