Tried using a 6-inch knife for butt joints on a big ceiling job in Austin last month...

I thought a wider knife would save time on the flat spots, but I ended up with way more sanding than usual. Learned that a 10-inch really is better for keeping those long seams smooth. Anybody else find that narrower blades throw off your finish on ceilings?

2 comments

2 Comments

sage_lewis101mo ago

Austin humidity expands the mud differently on wider knives, that's why.

anthony_fox901mo ago

Yeah I actually used to think it was more about the steel type than the mud, but @sage_lewis10 you really made me reconsider that whole idea. That explanation about humidity and wider blades actually makes a lot of sense once you think about how the mud binds differently. Definitely changes how I look at knife geometry for different climates now.