I'VE NEVER WORKED WITH PLASTER BEFORE. I'm planning on creating an archway in an existing door & creating two arched windows in an interior plaster wall. I'd like to retain the existing plaster wall as much as possible & not resort to having to sheetrock the entire wall.
1) Is it possible to not destroy the entire wall?
2) If so, what would be the "safest" route to take to avoid destroying the entire wall.
Maybe I'm missing something, but what you plan to do is no problem. It's just a matter of not getting crazy for risk of cracking walls if your cutting out sections. Other than that we've always just used hot mud to blend/patch into existing plaster walls/ceilings with no problems. If you have to patch in with drywall, no biggie since once it's blended and painted nobody but you will ever know any difference.