Stretching And Relining a Canvas

Since the painting, Plasma, was done on an unstretched cotton canvas I needed a method to display the entire piece without hiding the edges.

A stretched canvas usually has its edges wrapped around the wood stretcher bar and tacked in place. This should be done with a fresh canvas before the painting. That wouldn't work for me in this case. The technique used to restore old paintings by remounting them is called relining. The original canvas is removed from its stretcher frame and glued to a new backing, usually linen. I've seen this demonstrated at the restoration workshop of the Germanisches National Museum in Nurnberg, Germany when I was an art student volunteer. Its done on a vacuum table with archival, reversible glue. Museum quality restoration must use materials which can be removed without damaging the art should newer techniques become available to future restorers. These photos illustrate how I pasted strips of linen to the edges of my canvas from the back using rabbit skin glue.

This adds several inches of fabric with which to pull the painting using stretcher plyers around the edges of the stretcher. It is then stapled starting from the center of each side incrementally working towards the corners.

I did quite a bit of research and sought advice to choose the best method and to find a source for quality stretchers and braces. I haven't purchased stretcher bars in a long time. I have been using pre-stretched gallery wrapped canvas. I found that wood of the right type and dimensions are rare and expensive. Decades ago in Georgia I cut my own stretchers from local poplar and basswood . The miter joint used in this craft is unique and complex. It must be expandable after assembly to account for changing humidity and its effect on the canvas tension. I never found the correct name for the joint on any woodworking site, nor any instructions on making your own. I would just copy a commercially made example from an art supplier and scale it up to my materials. The closest name for this joint I found was a mortise and tenon miter. But that omits the subtle detail added to make it expandable using a small wooden wedge called a key. You may find this in photos of painters studios that include paintings turned to the wall exposing the back.
Making my own stretchers using this joint wasn't feasible for me since the 72 in. length of each of the four sides was beyond my machinery. So I finally chose a 72 in. stretcher kit from Utrecht Art Supplies
The package came damaged in shipping but their customer service was excellent. They sent a second package immediately and provided return shipping labels.