Picture a plaster wall. Now imagine that a significant section has been removed of it and now needs replaced.
Ive tried to replace the plaster with 1/2 inch only to realize the wodth difference im left with is 1/4th inch.
Is it possible to merge the two width differences by sanding the thicker one down untill its a gradual, unoticable slope?
Or will i just have to use 2 3/8's together to made 3/4ths?
Thanks for your time
You could taper the sections together with joint compound (though you wouldn't sand it into shape--that would be ludicrously laborious). However, you'd probably still see the transition at the floor and ceiling.
Better, use furring strips on the new section of wall to result in a flush finished surface. 1/4" luan plywood or OSB is cheap and easy to work with, or rip your own from 2-by lumber.
On a related note, I tend to prefer 5/8" gypsum board when I'm replacing plaster. It more closely matches the rigidity and strength of the plaster, and requires less furring. In some cases, none is needed.
Would be much easier to do in plaster, even if textured.
The images below, are of an old window opening, overlapped by a new double door install. As forgiving as that dark paint was (2007), if they painted that room white today (2016), it would still look like that door had always been there - 140 year old house. The last picture before the close-up, is all the further out that I blended, didn't need to go clear out to corners/ceiling.
Remove ALL loose plaster first, then add in this order;
Wood Lathe > Stapled Wire Lathe > Structo-Lite > Blue Tape > DuraBond > Light Weight Setting 90 > Thinned Light Weight All Purpose Bucket (Do all texturing here) > Prime > Paint > Done
Outside of a detailed explanation of the work flow - if you follow the instructions on each product, as it appears on the packaging, they will all work, exactly the way that they are supposed to.
Go with your plan & method of filling or even over-filling the areas in. You want to be as level to the old stuff as possible so the Mesh Tape can be equally filled in & over & humps feathered out onto both the old & new.
The thicker the drywall the better. Plaster is extremely good at sound insulation, so you want to match that mass with as much mass as you can. Any loose old plaster edges should be screwed (or even washered, see below) to the studs or lathe strips, so the old is as solid as the new.
The below Plaster Washers are great for old plaster re-attachment, but are thicker than the Mesh Tape so feathering-out will need to widen. Plaster Washers should only be driven-in until they're flat, a little more is still fine. These can be used in the plaster field or within a seam or crack, thereby fantastic for ceiling cracks & their then former falling-away bulges.
