what would you all say would be a good bf to stop bulking at?

It kinda depends. You could be "bulking" and gaining pounds of muscle and eating cake every meal and gaining pounds of fat too; opposed to gaining muscle and little fat on a good diet. I go be my lifts when i decide to cut.

Like A few months ago i set my goals to clean 265 and squat 450. And when i got there i started my cut. The goal of a bulk is to put on muscle. If you set goals in you lifts you know you've gained muscle when you reach them.

I would stop at 15% bodyfat or when you go up a pants size.

well i'm at 18.5% now. ive been lifting for 1.4yrs. I never really set goals for myself but ive definatly gained muscle ive gone from 153lbs to 173lbs( i'm 5'10 1/2). I whis I took befor and after pictures and done all my 1 rep max when i frist started but i didn't but I benched 210 yesterday (and when i started I could only do 125) and I deadlifted 305 so ive definatled gained a fair amount of muscle but yah im starting to notice im getting fat so I guess its time to cut.