Plaster cracking on angle beads

[CortinaV8]

I had a room skimmed recently and have noticed in places where there is an angle bead it has cracked slightly.

Thin coat beads were used.

Just wondering what would cause this? the beads were nailed into position, I assume it's some kind of expansion and contraction during the drying process between the different materials.

 

[Richard C]

I use a combination of grab adhesive & a staple gun to fix my angle beads. I found that nails can crack/split the edge of the existing plaster under the bead & won’t always hold the bead firmly in place. As to why it cracked I'm assuming the crack follows the same line as the inside edge of the bead? Either has the bead was loose & moved as it was setting or being finally trowelled off; it could be that the bead was either flattened out too much over the corner (they are formed slightly less than 90 degrees) or were not fitted particularly well, leaving the finish skim a bit thin over the inside edge of the bead; personally I’ve never had any problems with either method but the way I do them now is quicker, doesn't damage the exiting plaster edge & they never move on me.

You didn’t artificially heat the room when it was drying out did you