I've been researching drywall finishing techniques and have noticed that when a first coat of mud compound is used, a smaller 6 inch taping knife is used... then on the second mud application, a larger knife is used (usually 6 - 12 inch)... then on a third coat, a 10 - 12 inch knife is used.

Is this just personal preference? Why are progressively larger drywall knives used after each pass?


3 Answers 3


You're spreading the mud out over a progressively larger area so that instead of a small but sharp bump (or dip) in the middle of the joint, you have a much more gradual bump (or dip). That way, any irregularities in the surface are much less noticeable and can be easily masked by texturing.


Note that that progression only applies for "butt" joints where the unshaped short edges of drywall panels meet, not to long-edge joints where the edge is thinner to create a recess in the finished wall. On those edge joints, you just want to fill up the recess not bulge and feather it, so your knife only needs to be long enough to span the recess, or about 6-8".


I know the question is already solved but I learned a lot over the weekend watching drywall videos on YouTube. There are a number with Laurier Desormeaux posted by drywallgall that were really good.

  • I reccommend drywallgall's videos whenever I can. I used to hate drywall now I love it...
    – dfc
    Feb 25, 2013 at 3:12

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