My foreman swore by using a 6-inch knife for all butt joints, said anything wider was for amateurs

I tried it on a big commercial job last month and ended up with ridges so bad the taper had to come back and sand them down for an extra hour. Switched back to my 10-inch and got flat joints right away, no issues. Anybody else get stuck following bad advice from someone who's been doing it too long the same way?

2 comments

2 Comments

emeryn8317d ago

That 6-inch knife thing only works if you're doing light texture or really thin mud. For a commercial job with level 5 finish requirements, you need the width to bridge those butt joints properly. The 6-inch will leave a crown every time because you're not getting enough mud past the center of the seam. Your foreman probably learned that trick on small residential remodels where the taper just floats the whole wall with a thick texture anyway. On a big flat wall with any kind of lighting, those ridges show up like a sore thumb. You did the right thing switching back to the 10-inch.

oscarwright16d ago

Yeah but a 6 inch knife has its place even on commercial work. It's not gonna crown if you feather the edges right and hit it with a 10 or 12 inch after. The trick is using it for the first coat to save mud, then widening out.