I've been mounting these direct watercolour plein air landscapes onto 6x8 inch deep cradled wood panels using gel media (being very careful not to get any on the painted surface or sides of the panel). Then, they are weighted down overnight...I use my leather-bound Shakespeare as they are the perfect size and weight. Once dried well, I apply a layer of D'orlands Wax which is a very old medium that has been traditionally used in oil painting and works very well as a sealant for unframed watercolours. Finally, I attach D-rings about 1/3 of the way down the back of each piece and wire using plastic coated framing wire as per gallery recommendations. I really love how contemporary they look. The Paint Spot art supply store in Edmonton has posted a great step-by-step video on the process.