This was meant to be a quick mounting project, but soon became my first experience with plaster conservation.
The hinging was a straightforward Japanese paper tab mount. I cut the window in the mount board and hinged it to the backboard, pasted Japanese paper tabs to the back of the watercolor painting, and pasted the tabs to the mount.
That is when I was presented with a plastic bag of plaster fragments. The plaster on the frame was cracking and pieces falling off. I was asked to consolidate the plaster and re-attach as many of the fragments as possible.
All exposed surfaces of raw plaster were consolidated using a 2% (w/v) solution of Paraloid B72 mixed with 50/50 (v/v) acetone/IMS (Industrial Methylated Spirits).
The detached fragments were adhered to their location on the frame using a 30% (w/v) solution of Paraloid B72 in 50/50 (v/v) acetone/IMS.
The client requested that the exposed white plaster be toned to match the rest of the frame so it would not detract from the delicate painting. Another layer of B72 was applied to the plaster and various shades of brown and gold acrylic paint were applied.