Northamptonshire 234 for 0 (Vasconcelos 126*, Newton 85*) trail Glamorgan 570 for 8 dec (Root 126, Labuschagne 121, Carlson 111)
After Glamorgan's run-fest on the opening day, it was their own bowlers' turn to toil on the second, as the Sophia Gardens pitch continued to offer little, if any, assistance.
By the close, Northamptonshire's openers, Ricardo Vasconcelos (126*) and Rob Newton (85*) had shared an unbroken partnership of 234. They still required a further 187 runs to avoid the follow on, but on the evidence so far, there is little prospect of a positive outcome on such an unresponsive strip.
When play resumed, Glamorgan added 137 runs in the morning session, before declaring during the lunch break. They lost Billy Root to the fourth ball of the morning, when the debutant left-hander struck a low catch to backward point. Root and Kiran Carlson had added 172 for the fifth wicket, before Carlson, who added a further 10 runs to his overnight 101, was taken at first slip.
Graham Wagg and Marchant De Lange quickly followed, but Chris Cooke then accelerated to strike a rapid undefeated 70 from 87 balls with a six and ten fours before calling a halt to the innings.
Needing 421 to avoid the follow-on, Northants' openers set off confidently. Vasconcelos - a 21-year-old from Johannesburg who has a Portuguese passport - struck two boundaries in Michael Hogan's second over, and was the dominant partner against the five-man Glamorgan pace attack.
After scoring 56 and 79 here last summer, Vasconcelos was dropped at second slip after scoring 21, and was uneasy at times against the legspin of Marnus Labuschagne, but he deserved his fourth first-class century which included 15 boundaries from 189 balls.
Newton was no less effective, as the pair went past the 150-run stand, with Glamorgan, like Northants, resorting to seven bowlers. The most effective was Labuschagne, who was treated with respect and ended his opening spell with the commendable figures of 11-1-29-0.
With the pitch as true as it was when the first ball was bowled on Thursday morning, Northants could look to bat on to an imposing total, or declare if and when they reach maximum batting points.
The latter would be a popular decision with the spectators, especially if they witness a run-chase on the final day, otherwise there will be little to interest them if the game meanders to a draw.