A rip in a canvas painting will essentially destroy the painting's beauty and value. While you likely won't be able to salvage the painting's value, you can repair the rip and make the painting look as close to new as possible. You should only attempt to patch up the painting if you are able to not only repair the rip, but also paint over the canvas in the torn area to restore the painting.
Instructions
1. Place the painting face down on a clean table. You should only need to remove it from the frame if the frame is in the way of the rip. Smooth out the canvas so that the edges of the tear are as close together as possible, if not directly touching each other.
2. Cut out two pieces of linen into a shape large enough to cover the entire torn area.
3. Place a strip of thermoplastic adhesive on the tear. Hold the original canvas taut, possibly with an assistant's help, as you remove the strip's paper backing and place the adhesive over the tear.
4. Place one linen piece over the adhesive strip and apply heat with an iron to the linen and strip, heating the adhesive so you can remove the strip's other backing.
5. Remove the linen, peel off the adhesive's other backing, place the other piece of linen over the adhesive and apply the iron again to bond the linen with the adhesive.
6. Turn the painting and fill in any holes in the canvas, if needed, using a special putty like gesso primer. If you can't find this type of primer at an art supply store, mix warm water, gelatin and chalk instead.
7. Wait at least two days for everything to dry. This can vary depending on the condensation in the air, both outside and in your home.
8. Paint over the tear, canvas patch and all traces of putty or gesso using the same paint type and colors used to create the original painting.
