MITRA Forum Question Details

​There is nothing wrong with the first scenario that you have proposed so long as the wooden support is of decent quality (and therefore is not prone to splitting/cracking and/or lots of movement...). 
As for the second....this is a very good question and we are happy to have this recorded on the forum. I am including a screenshot of an excerpt from The Conservation of Easel Paintings (ed. by Joyce Hill Stoner and Rebecca Rushfield) from an excellent chapter written by conservators Carolyn Tomkiewicz, Mikkel Scharff, and Rustin Levenson. We would not advise using something like construction foam for the very reasons that you have already cited. But certainly something like polyester batting can be easily obtained and is very lightweight. These images will also help to give you an idea as to how conservators construct padded backing boards. Let us know if you have additional questions.PaddedBackingBoards copy.jpg

​​I would think that screws made for metal and finishing washers would work just like it does for wooden stretchers. As for placing foamcore inside the stretcher bars and then covering with additional canvas...I am not really sure I see the need for the additional canvas except if you want to provide some sort of buffering layer for a vented backing board. The padded backing board should be fine in this instance. You could also do something called a "cami-lining" but that might be overkill at this stage depending on the materials and technique you use but it is certainly an option. See the attached photo from the same chapter cited above.CamiLining.png

That should work as long as it is secured to the stretchers in some manner and not exerting pressure on the canvas. FomeCore does become more brittle over time. This is not really an issue for backing boards but it may be best to not have it in contact with the canvas. A quality Gatorboard or the like would probably be better. I am not sure that Coroplast is the perfect choice as, if I am remembering it correctly, there is has a corrugated construction that is evident in the surface topography.

I have even adhered hardboard to the front of a strainer (it is called a strainer if it is not keyable). This is very similar in concept to the panel-back strainers used by some early 16th-century Italian and Spanish oil painters as well as the panel back stretchers (keyable, despite the incorporated panel) used by some Pre-Raphaelites and Hudson River School Painters in the 19th century. This practice has been determined to be very beneficial.

The size of your works would probably preclude the use of heavy materials like hardboard but a lighter weight material like Gatorboard may be a good idea.

Yes, the panel back strainer is generally preferable except in areas in regions with very high and unrestrained humidity where there is the possibility of mold growth. The panel helps to keep the canvas in plane, searves as a buffer against rapid changes in the environment and protects the painting from impact form the back and even to a certain extent from the front. A keyable panel back stretcher is even better, but requires much more refined woodworking skills

​It has been a few years sinse I read all the way through that section. That modification looks really great. Go with it.