Repairing crazy quilts. Well. These are pretty difficult to work with, in my estimation. Hence the title of this post!
Most often, the problem is what are called "shattered" silks. This is disintegration caused by the dyes and processing that were used on the silks in the late 1800s and into the beginning of the 1900s, basically in the Victorian era. Metal salts were added, both as mordants on the darker dyes, and to add that famous silk rustle, and to make the silks heavier since they often were priced by the pound. (So you see, there have been unscrupulous businessmen around for a long, long time.)
The problem is that there is no way to reverse or stall this damage. Keeping the quilt out of the light and in even temperature and humidity can slow it down, but that is the best deal you're going to get.
Another problem is the lovely embroidery. The fabric under the embroidery can't be replaced unless the fancy stitches are removed and then re-embroidered after the patching.
The more I work on these beautiful, jewel-like quilts, the less and less I choose to do.
Here's one technique that I use.