Steve Gangluff fired a bogey-free 65 to join Darron Stiles, Chris Tidland, Ben Bates and Hunter Haas in a tie for third place at 9-under-par 133.
Cotner, whose lone victory on the Nationwide Tour came at the 2000 Oregon Classic, picked up a birdie at the par-5 second and added a birdie at the par-3 fifth to reach 9 under.
The 33-year-old kept on cruising around the turn with a birdie at the par-4 10th and tallied a birdie at the par-4 16th to move to minus-11. Cotner then parred the last two holes to complete the first two rounds without a single dropped shot.
'It was pretty much the same round as yesterday,' said Cotner. 'I didn't take advantage of a couple of holes like I did yesterday and that was the difference today.'
Elder started on the back side at Crestview Country Club and jumped out of the gate with back-to-back birdies from the 10th. He then birdied the 14th and ran off three consecutive birdies starting at the par-4 16th to go out in 30.
Elder kept the birdie barrage going at the par-5 second and made it two in a row with a birdie at the third. The 29-year-old faltered with a bogey at the sixth, but managed a birdie at the ninth to match the course record with a round of 63.
'I went out and tried to fire at every pin because the conditions were so soft,' said Elder, a two-time winner on the Nationwide Tour. 'If it stays like this you're going to have to make a lot of birdies.'
Jimmy Walker, who is searching for his third victory of the season and an instant promotion to the PGA Tour, carded his second straight round of 67 to join Gavin Coles, Bill Lunde and Sean Murphy at 8-under-par 134.
Todd Rose shot a 63 of his own Friday to finish in a large group at 7-under-par 135.
Defending champion Jeff Klauk posted a 70 to finish in a tie for 39th at 4-under-par 138.
The 36-hole cut fell at 3-under-par 139 with 79 players qualifying for the weekend.