Thanks for the question. When designing an adhesive joint, one of the most important factors is understanding the substrate material, texture, and any paint or coatings. In this application, it sounds like there will be a wide variety of materials, textures, and coatings. The wall must be well unified and clean at a minimum for any adhesive bonding, so you will likely find that there are some surfaces that are problematic (i.e. chipping paint, rotting wood, difficult to bond paints, corroded metal, etc).
The other substrate is equally important. We have a range of plastic bonding adhesives, but the specific plastic and any coating on the plastic will make a difference. For instance, low surface energy plastics such as polyethylene and polypropylene require specific adhesives and/or surface prep techniques to get good bonds. Please leave a comment below if you’d like to discuss the plastic in detail.
One option you could consider is using a thick, double sided bonding tape, perhaps with a primer. 3M™ VHB™ Tape 5962 would be my first choice for testing in this application. It is a very conformable acrylic foam tape with an adhesive that works on a broad range of substrates. It has excellent outdoor performance and has been used in a wide range of outdoor applications. Before bonding, make sure the surfaces are clean, in good shape, and have a texture that allows good contact with the tape (highly textured surfaces can reduce bond area). For additional robustness, you could use 3M Primer 94 on the surfaces.
Post a comment if you have follow-up questions. We’d love to hear how this works for you out in the field.