In another house I own, two weeks ago, a painter was painting the textured ceilings, and pointed out where there was a 5 inch bubble that had extended downward from the surface, supposedly after Kilz 2 primer was applied. It may have been there before, but I'm not sure. I had him skip the ceiling painting till I had a chance to evaluate a repair. Yesterday I figured, what the hell, I'll try something different as to the method of repair. Taking a utility knife, I cut a circle around the distended area, finding my way by tapping lightly with my fingertip for loose areas. The entire chunk of textured ceiling dropped right out into the palm of my hand, unbroken. Lightly sanded the exposed area, no feathering, then applied a really heavy coat of Kilz 2 to the area, pulling the brush outward radially from the center of the area, to help rebond any looseness at the cut edge area. Took the removed patch and pressed it into place with the palm of my hand, aligning cut edges carefully. The excess Kilz oozed out at the joint of course, and I blotted it up as it appeared, all the while applying pressure continually and gradually to the patch. I then used a brush to clean up the joint line, using light swishing motion. The patched area has now dried and completely disappeared into the rest of the ceiling. I did this on a lark, as I believe in trying new and various techniques, as long as it belongs to me, and the job is facing you anyway. This is how you learn new methods. I started to try injecting inside the bubble with a hypodermic needle, but chose this method instead, due to possibly trapping air underneath. . I'll wait at least another week before painting this area, to allow thorough drying. For anyone interested, I'll post after painting to let you know how it works out. It was a hell of a lot cheaper and easier than trying to reblend new material into the area to match properly. I was pleasantly surprised how well it all worked.
RJ