A good frame will keep the cells sturdy and should seal the cells in a waterproof material. Common sealing methods include EVA film, a glass face, silicon and epoxy based sealants. Each method has their pros and cons. For this panel I decided to use epoxy because it was easy and was a non-glass method of strengthening the wood. Also, I had a lot of it around from a project that my dad is currently working on.
The main disadvantage of using epoxy is that it yellows, and you never fully know when or how much it is going to yellow. The plan was to give the epoxy 3 days of drying time and then cover it with a clear UV protection coat.
To make sure the cells are properly attached to the base, and do not buckle, silicone is applied in a thin layer underneath the cells. I used a squeegee to spread it inside the area of each cell. Applying the cells now, make sure to apply silicone generously to the two wire leads. Those leads will stick out of the surface a bit, but this is okay since the epoxy will cover them.
Mixing the epoxy:
I used a marine grade, indoor (ironic), and most importantly, self leveling epoxy. It needs to be self leveling or it will leave air bubbles. Almost all epoxies need to be mixed with a 1:1 ratio (for two part epoxy). In my case I used 400mL or epoxy, so 200mL of hardener and 200mL of epoxy. I mixed the epoxy for aprox. 10 minutes and poured it thoroughly over the cells, starting with the cracks, ending with the surfaces.
The cables and cells are now attached to the back plate now. I leveled the panel out on our table by adjusting several wooden blocks. The leveling of the panel is critical, otherwise the epoxy will pour out one edge.
I ended up using about maybe 400ml of epoxy, I wasn’t quite sure how much is enough so I had to do several pours. During this time the use of a flame such as a propane torch is required. Heat raises the air bubbles to the surface where they pop, leaving a smooth surface.