River bluff raise, is this the right time?

I almost never bluff raise the river (my secret is out) but the set up seemed good here (although I think I needed to consider the villain more carefully, as he is 42/4/.8, so probably not the folding type which was a mistake). He raised me on the flop, but then backed off on the 3rd flush card on the turn. I bet out with the 2nd nut flush draw and overcards. Because of the villain's fear of the flush and then my bet, I was playing that he had me on the flush, so when he bet out the river, where 99% of the time I would have folded, I raised, so he would put me on the made flush. He waited almost the full amount of time and called. Is this a reasonable time to bluff raise the river? Was it just the wrong opponent?


Party Poker 5/10 Hold'em (9 handed) FTR converter on zerodivide.cx

Preflop: Hero is MP1 with K[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/club.gif[/img].
UTG calls, 1 fold, Hero raises, 2 folds, CO calls, 2 folds, BB calls, UTG calls.

Flop: (8.40 SB) 4[img]/images/graemlins/diamond.gif[/img], T[img]/images/graemlins/diamond.gif[/img], 6[img]/images/graemlins/spade.gif[/img] (4 players)
BB checks, UTG checks, Hero bets, CO folds, BB folds, UTG raises, Hero calls.

Turn: (6.20 BB) 3[img]/images/graemlins/diamond.gif[/img] (2 players)
UTG checks, Hero bets, UTG calls.

River: (8.20 BB) 8[img]/images/graemlins/club.gif[/img] (2 players)
UTG bets, Hero raises, UTG calls.

Final Pot: 12.20 BB