I have to fix a problem spot on a 45 degree ceiling joint. The tape is coming loose, but only in a two or three ft. section. I intend to cut out the bad spot; mud in some joint compound, tape, etc. My question is how can I be sure to keep the same joint line from wall to wall? A corner trowel is for 90degrees, so that won't work. Is it pure patience and skill? Just askin.
Kind of. Since you're just doing a small section , that's about it. If you have a 6' straight edge or even a straight piece of trim or something, you could hold that on the line to see how you're doing.
If you were doing the whole run, you could get this flexible corner tape that has plastic embedded in it to keep it somewhat rigid for odd angles.
It would be at a pro drywall store, but I think HD has something like it.
I agree with Brush, it is patience and adding layers of joint compound until you get a line that looks good to you. I have never seen a pro drywall person use one of those 90 degree knifes. I have only seen the flat 6" blades used. Spread your compound on both sides of the angle, fold your tape in half and smooth in the tape at the ceiling and then the wall in seperate passes which may pull out some of the compound, and that is ok. Let it dry then work only one side of the angle at a time, i.e. do a coat on the ceiling and let that dry and then do the wall side of the angle (repeat till it looks good). I find it extremely difficult to get both sides of the angle smooth at the same pass.
Fantasy Walls and Windows