The duo stands at 9-under-par 135 -- a lead that will remain safe when 10 players return to Shadow Hills Country Club on Saturday morning to complete their second rounds.
Play was delayed by 65 minutes in the morning because of fog, then suspended due to darkness. None of the players remaining on the course are within three shots of the lead.
Tim Wilkinson and Chad Collins both shot their second consecutive 4-under 68s to share third place in the clubhouse at 8-under 136.
Quinn, 41, is the only player to have played in every Oregon Classic since its inception in 1998. He was cruising along Friday until going double-bogey, bogey at his 16th and 17th hole -- the par-4 seventh and par-3 eighth.
He was alone in the lead at 11 under when his tee shot at the seventh found the trees. At the eighth, he three-putted from 20 feet.
'Had I shot 63 or something, that would have been special...but I gave a couple back,' Quinn said.
Barnes' round was less up-and-down. He had six birdies and two bogeys to climb with Quinn from a tie for fourth place overnight into a share of the lead. He made birdies at the 15th, 16th and 18th to join Quinn.
The 2002 U.S. Amateur champion found himself making swing changes as the round went along.
'I hung in there, hung in there, hung in there and then when I figured it out I took advantage of it and played well on the way in,' Barnes said.
First-round leader and Oregon native Jason Allred struggled to a 79 and tumbled all the way into a tie for 69th place at even-par 144 -- one shot over the projected cut line.
This is the 500th event in the 17-year history of the Nationwide Tour.