In my post of the picture frame, I mentioned that I had used PPA (Perfect Paper Adhesive) to glue the designer paper to the frame but that the paper came unglued and wrinkled when I painted Varathane on the frame. Susan Pickering Rothamel, president of USArtquest and developer of PPA emailed me the following comments:
"If you use PPA as the 'decoupage' or 'collage' medium, then you do not need to use Varathane. In fact, the PPA is a stronger and more water resistant, UV resistant medium, even producing less tack, then the Varathane itself. If you want a shiny finish, use PPA gloss. If you want a satin finish – mix PPA 1/2 matte and 1/2 gloss. However, if you do want to use the Varathane anyway, understand that it will yellow over time. PPA will not. Also, if you choose the Varathane, even a PVA/Elmers/Mod Podge, etc. glue will lift, if it isn't REALLY nailed down.
PPA is used often under Varathane by wood artisans and experimental artists. It is necessary to make sure the paper is glued under every teensy area, and even on top. The paper should be fully encapsulated in PPA. Then you must wait for it to dry thoroughly before adding any type or urethane product. However, using the PPA as the finishing varnish needs no extra drying time. Drying happens by 'curing' rather then evaporation. Therefore, the longer you wait, the more successful the piece will be. Easily a day or two in between coats." She further gave these directions for adhering paper to a wood frame or plaque: "You apply PPA to the frame, then continue to use the PPA'ed brush as you apply the paper, brushing even more adhesive over the top of the paper, smoothing it as you go. For the absolute BEST success, spritz or dunk each piece of paper thoroughly in water before applying it to a frame (or any other surface. This assures that every fiber is fully wetted, preventing unsightly buckling or bumps. Make sure that every area though has adhesive under it, or you'll have bumps when the paper dries. It is quite a simple process, and works everytime with the few tips I've mentioned." Susan graciously permitted me to post this information on my blog. I hope it will help someone else with their creative projects.