My bullnose corners took 3 days longer than I planned

I was working on a fireplace surround last week and kept messing up the bullnose corners on the firebrick. Thought I could just grind them freehand like the videos show, but every single one chipped or came out uneven. Ended up spending three full afternoons redoing the same four corners before I broke down and built a jig for my grinder. The jig took maybe 20 minutes to make from scrap wood and a hinge, and after that the corners were perfect in one pass. Anyone else got a tip for doing bullnose work faster without a specialized machine?

3 comments

3 Comments

nguyen.morgan11d ago

Nah, I gotta push back on this. You blaming the grinding and not your setup from the start is just skipping over the real problem. Freehand grinding bullnose on firebrick is never gonna work well if you haven't dialed in your tool or practiced enough. The jig idea is fine, but honestly, spending three days messing up four corners sounds like you weren't paying attention to your speed or the grit of your wheel either. A good trick is to wet the brick a little before grinding, it cuts cleaner and chips way less. And if you don't have a jig, just use a cheap masonry rub brick to smooth out the curve after grinding, it saves a ton of time fixing mistakes.

christopherw3411d ago

Three days? Four corners? @nguyen.morgan I gotta say, that is brutal. I would have thrown my grinder through the window by day two. I use a 24-grit diamond cup wheel and run it at a lower speed, like 4,000 RPM, and that keeps the chipping way down. Did you try a rubbing brick first to see if you could save any of those messed up corners or did you just grind them down flat again?

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adams.uma11d ago

Honestly, I think everyone is missing the real issue with those brick corners. You guys are all focused on grinding technique and jigs, but what about the mortar mix you used? If your mortar is too hard or too soft, it makes the whole brick act different when you grind it. I've seen guys spend hours chasing chipped edges only to realize the brick batch was bad from the start. Sometimes the firebrick itself has hidden cracks or soft spots that show up the second you hit them with a wheel. Before you touch another corner, try tapping the brick with a hammer and listen for a dull sound. If it doesn't ring clear, you're fighting a losing battle no matter how good your grinder setup is.