Drove myself nuts chasing a mud cracking issue for weeks

Turns out it was something stupid I was doing with my knife angle on butt joints. I kept seeing these little hairline cracks show up after the second coat dried, mostly on the long seams between boards. My buddy Mike came by my job in Arlington last Tuesday and watched me work for like 5 minutes. He goes, you're holding that 12 inch knife way too flat on your second pass, you're basically just scraping off the compound instead of pressing it in. Soon as I tipped it up a few degrees and actually pushed the mud into the joint, the cracking stopped completely. Been doing this for 4 years and never caught that simple thing. Anybody else deal with a mystery issue that turned out to be just a bad habit?

2 comments

2 Comments

mason_davis10d ago

pressing it in" - that's the exact phrase my buddy Tom used when he was bitching about his drywall work. He'd been fighting these same little cracks for months, thought he was buying bad mud or something. I watched him one afternoon and saw he was practically wiping the joint with the knife, not forcing anything into the gap. Soon as he angled up and put some muscle behind it, his work got way cleaner. Sometimes it's the tiniest thing you're doing wrong that messes everything up.

charlesb4210d agoTop Commenter

Laughing at myself here because I'm the exact opposite. I press in way too hard. Last time I did drywall I was so determined to "really get it in there" that I pushed so hard the knife slipped and I gouged a chunk out of the wall. Had to start all over. My dad still brings it up, says I've got a heavy hand like my grandpa who used to split lumber by accident. So I guess there's a sweet spot between barely touching it and trying to hammer it home. I'm still looking for that spot.