repairing 45 degree joint in ceiling
Just my opinion, but corner trowels are useless anyway (I'm sure I'll get some feedback on that). Cut out the bad section of tape, apply mud to both sides of the angle with a 4" or 6" knife (whichever you have), crease and set the new tape in place, wipe the excess mud from each side to embed the tape. After allowing to dry fro 24 hrs. apply a coat of mud over one side of the tape. Allow to dry 24 hrs. and apply a coat of mud to the other side of the tape. Sand carefully, touch-up if necessary, let dry, and sand. Yes there is a certain amount of "finesse" involved in getting an "off angle" correct, but if you take your time, it will come out fine. More coats of mud may be necessary or a bit more sanding, but it's do-able....
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