Why do Drywall Knives Have to be So Darn Flexible?!?!? :)

So I'm drywalling for this first time in my life. I have to say, it wasn't the nightmare most people have warned me about. I'd like to think I'm not half bad for a first timer.

I've equiped myself with some descent 4", 6", 8" and 12" knives from the big box stores.

One thing I've been struggling with is the last coat on the taped seams. The knives are flexible so no matter how little pressure I put on it, the knife still bows enough to squeeze out the fresh joint compound in the seam.

Why do drywall knives have to be flexible? It would seem that if they were rigid, it would be easier to produce a flat surface. After fighting with the seams for a while I was able to get it "close enough" but not perfect...what gives?!?!?

Your advice is as always, much appreciated.

 

Mud spreading is an art.

How many coats are you applying and how wide is your final coat?

Your first coat is the fill coat - it's just to get the crack filled.

Your follow up coats are finish coats - the goal is to feather the drywall out to smooth it out to the point that it isn't noticeable. Perfectly flat isn't required - smooth and flat LOOKING is.

Generally I apply a very very gentle angle to my tool so that the side close to the seam is ever so slightly higher than the edge on the clean wall.

 

I agree....it is definetely an art. My first coat was with all-purpose. Mesh tape on the tapered ends and paper tape on the butt joints and inside corners.

I then did two coats of the lightweight stuff.

I'd have to say my final coat is about 5 inches wide.

When I hold a 12" knife up to it to see how flat it is...I can see a crack of daylight through the seam. Probably about 1/32 of an inch. I feel that it is good enough but I had to fight for it.

Everytime I went to apply more joint compound I ended up scooping most of it out because of the flexibility of the blade.

 

On your skim coats thats probably because you're putting too much on.

Don't worry about perfectly flat. After you coat, step back and look at the seam from multiple angles. If it looks smooth and even, you're good.

 

I couldn't imagine applying more than a little bit of mud with a knife that wasn't flexible. I agree with chaeberle that you are probably applying too much mud at a time. You want a fair amount of j/c in the middle of the knife so it spreads out as you are pulling it smooth. I like to tape with an angled/offset 3", use a 6" knife for the next coat and finish with a 12"or14" knife.

Finishing drywall isn't overly complicated, just remember it's easier to add more mud than to sand off the excess. If you see areas that need more attention after you've primed, fix them, reprime those areas and you should be ready for paint