Skim the entire surface. And the adjoining edges should be tapered so as to create a depression. Shave a tapper using a knife. Don't worry about how it looks,,,,or fits....you trying to create a crevasse for the tape to overlap and for Compound to be pressed into.
In truth, without floating out the Compound far away from the joint, you will not be able to disguise the joint's elevated surface if FiberGlas mesh tape is also used...and it should / must be used.
Do an initial "skim" coat over the Tape joint, then a light coat with a 12" Knife, then Skim Fills above and below the Joint's edges, barely blending those edges....then an entire Skim coat that is lightly sanded smooth, then skimmed again and sanded, primed, and the sprayed.
Dust the sanded skim coats off before doing another coat or starting to paint.
Sounds like a lot...but it's all really just taking care to do it right. and you must do it right the first time because it would be a big 'ol PITA to have to redo after spraying.
Bit I'll say this...if you do do it right, the fully skimmed, sanded surface will be an exceptionally good surface to work with.
In truth, without floating out the Compound far away from the joint, you will not be able to disguise the joint's elevated surface if FiberGlas mesh tape is also used...and it should / must be used.
Do an initial "skim" coat over the Tape joint, then a light coat with a 12" Knife, then Skim Fills above and below the Joint's edges, barely blending those edges....then an entire Skim coat that is lightly sanded smooth, then skimmed again and sanded, primed, and the sprayed.
Dust the sanded skim coats off before doing another coat or starting to paint.
Sounds like a lot...but it's all really just taking care to do it right. and you must do it right the first time because it would be a big 'ol PITA to have to redo after spraying.
Bit I'll say this...if you do do it right, the fully skimmed, sanded surface will be an exceptionally good surface to work with.

























