I shall never get you put together entirely,Pieced, glued, and properly jointed. (1-2)
The extended metaphor of the poem is about the speaker trying to put the statue back together. If we're going with the idea that this is about a woman grieving for her father, you could say this is about her trying to make sense of his death. We wonder if she feels as broken apart emotionally as the statue is physically.
A blue sky out of the Oresteia Arches above us. O father, all by yourself (16-17)
The speaker drops an allusion to a whole bunch of suffering with the mention of the Aeschylus's Oresteia. This tragic trilogy tells the story of a father who kills his daughter, which causes his wife to kill him, which causes his son to kill his wife. The whole time another daughter is left to mourn it all. By giving a shout out to this epic tale of suffering, the speaker places her and her father's suffering on a truly grand scale.
My hours are married to shadow. (28)
Even though the speaker doesn't spend a lot of time whining about it, lines like this definitely make us think that she's pretty depressed about this whole thing. Seriously, being married to shadow can't be too much fun, right? You could see this line as meaning that the speaker feels completely unable to escape the suffering caused by her dark depression.