My trick for getting through thick fire caulking without ruining the bit

I know everyone says to use the designated firestop bits for drilling through fire caulking, but I found a better way that saved me a lot of trouble. On a job in a hospital basement last month, I had to run coax through four separate fire-rated walls, and my regular drill bits kept gumming up within two holes. The problem was the caulking was that hard, intumescent stuff that turns into cement when it heats up from friction. I tried soaking the bit in water between holes, but that just made a mess and slowed me down. What finally worked was switching to a standard masonry bit and running the drill at low speed with steady pressure, no pulsing. The masonry bit doesn't clog like a regular twist bit, and the low speed keeps the heat down so the caulking doesn't harden around it. Has anyone else found a tool or method that goes against the usual advice for these firestop jobs?

2 comments

2 Comments

henry_moore5510d ago

I used to be dead set against using masonry bits for anything but concrete and block. Thought it was a hack job, not a real solution. Reading this, I can see the logic though. That intumescent stuff is a beast and standard bits just don't handle the heat and gummy mess. I might have to give this a try next time I'm in a ceiling grid running cable through a firestop. Sure beats stopping every two holes to clean a bit and losing your rhythm.

thomas29110d ago

Does that stuff mess with the masonry bit's carbide tip at all?