Several posts ago, I described my approach for mounting paper or unstretched canvas to board. The idea is that, to save weight and space when travelling, you can paint on gessoed paper or canvas that is taped or pinned to a backboard. Then, once you are home, you can either archive these paintings in a box (a sweater box slid under the bed and left there for posterity is ideal!) or, if you really love a piece, you can mount it and then frame it.
I thought it would be helpful to shoot a video of this method. Here it is.