How to Mount a painting to be placed in a frame with glass or acrylic protection :
First take acid free foam core the intended frame size. Using a spray adhesive (3M Super 77 spray adhesive is strong and re-positionable), attach a thin layer of cotton batting to the face only of the foam core. Then center the silk painting on the foam core/batting and start attaching the silk by putting straight pins through the silk into the sides of the foam core.
All four sides will be attached by these pins about an inch apart. If the painting needs to be adjusted, just remove the pins related to that portion of the painting and make the adjustment.
At this point, an acid free museum quality mat can be added, in the fashion of a watercolor painting, or it can be framed without a mat. If not using a mat, you can choose not to cover it with glass or acrylic. Spacers between the glass and silk can be added for air circulation and to prevent moisture from collecting.
In any case, use UV protected glass or acrylic and for a really great look, go for no-glare glass or acrylic. Both the UV protection and no-glare options will add additional costs.