The home side led 15-6 at half-time with tries by fullback Robert Smith and centre Ian Marsh, before teenage fly half Gavin Ashman came off the bench and converted his own well-taken try late on.
Blackwood stay third from bottom and only had three Jeremy Lloyd penalties to show for their efforts.
Bargoed stay in second place thanks to their runaway second-half performance in their four-try romp at Newport Saracens. It was 10-all at half-time, but Bargoed flyhalf Jamie Howells went through the scorecard with a 19 point haul that included a try, four conversions, a penalty and drop goal.
Other tries by wing Lee Pearson, centre Darren Humphries and scrum half Mike Roberts put paid to Saracens.
Beddau announced themselves as serious title contenders after they posted a 35-3 win over Pontypool to secure third place in the league. Left wing Steve Robinson crossed for two tries in their six-try romp as centre Nathan Walters, flanker Steve Cole, right wing Darren Pearce and lock Damien Adams also touched down.
Bottom club Ystrad Rhondda came within a whisker of grabbing their second league win of the season as they lost out 19-15 to Fleur De Lys. Tries by wing Daniel Phillips and flanker Nathan Hughes were cancelled out by Fleur’s scrum half Darryl Cook and wing Matthew Davies.
In Division One West, second placed Narberth were humbled by confident Bridgend Athletic in a hard-fought battle. The 17-7 half-time score stood until the 78th minute before Steve Lewis scored an interception try from his own 22 which sealed the victory.
Narberth were down to 14 men for most of the game after lock Chris James was shown a red card for punching after just 25 minutes.
Bonymaen are still top of the table after their 16-12 win at Carmarthen Quins, but not until the hosts had fought their way back from a 13-0 half-time deficit.
Two tries saw Bonymaen cruise into a comfortable lead until Carmarthen scrum half Ricky Richards and centre John Morgan touched down before the Bonymaen fullback made the result safe with a penalty.
Cwmllynfell moved into second place with a 32-23 win at Loughor as they outscored the home side by four tries to three.
Bottom club Builth Wells went down with a fight in a second-half battle of the kickers as Dunvant’s Alun Bramwell kicked two penalties in a 6-3 win.
