I'm using 20 minute setting compound to cover a large rectangular patch. I mixed 1 lb of powder with about 1.5 cups of water, and am using a 12" knife. This picture:
shows the the result I'm getting when spreading the compound on the wall. The ~1/8" holes (green outline) from some internet research seem to be air bubbles (I guess I'm supposed to whip/mix the mixture better to prevent those?), but what's the deal with the crazy jagged edges (red outline)?
I get those same types of very large (~2") holes in the center of the area when I go back over the area with the knife as well, so I keep going and going pressing harder and harder and eventually the big holes go away… but I'm back to having no compound on the wall haha.
How do I make this compound spread more smoothly?