Splay angles in veneer plaster (or conventional plaster) ?
An inside corner more than 90o is called a splay angle. Check out this mystic secret.
Splay angles on veneer plaster can be straightened using a 6 foot rod (featheredge). You'll want to straighten the basecoat and the finish coat.
For stucco or conventional plaster basecoats, 2 strings are used. The strings are set close to the center of the angle, not one string right down the center
These strings must be plumb side to side. We used a 6 foot level. The strings don't necessarily need to be be plumb to the wall thickness. If these strings are plumb, your splay angle will be straight every time.
Too bad I don't have more pictures. I hope you can figure out what is going on. The next step is to pack mortar behind the strings forming vertical screeds.
More about screeds here...
