I haven't had the slacking problem with BC canvas, but I have a possible solution to slack canvas that SOMETIMES works. Instead of re-stretching, try misting the back of the canvas with water from a spray bottle--not soaking it, of course, but quite damp. Often the canvas will shrink as it dries, pulling tight. This is also sometimes an effective way to remove dents in canvasses where they have been accidentally poked.
One additional comment about Glamour II. Unlike ClearShield Type C, which sprays fine from a siphon HVLP, Glamour II requires a gravity feed HVLP gun (as noted on the BC website). Even at the recommended dilution or above, Glamour II just doesn't work well with the siphon type gun (such as the inexpensive Wagner units). With the recommended dilution for spraying and the correct kind of gun however, I've had no problems at all with cracking, stretching problems, etc.
All this being said, I have a slight preference for ClearShield Type C. It's simply easier to use (easier to spray, able to be used with inexpensive siphon feed HVLP guns, requires no dilution, and seems to remain more flexible for somewhat longer than the Glamour II).
David V. Ward, Ph. D.www.dvward.com
David V. Ward Fine Art PhotographyMy question
Has anyone had recent problems with the BC canvas slacking off after stretching? In the last month or so we've had to re-stretch an alarming number of pieces that have slakened off visibly a week or two after stretching. Everything was fine before and nothing has changed with the procedure. Has anyone had similar problems?