Commercially constructed solar panels are usually put together using high grade and durable but expensive materials. This is because they have to fully warranty their product for a very long time and can't afford to use materials that need maintenance.
Here's where we can save a great deal of money! Where the commercially made panels use aluminum, we can use wood and just make sure we seal it very well to withstand the elements.
Essentially we'll be constructing a shallow wooden box. Plywood makes a good backing or bottom of the box, and just about any type wood for the framing or shallow sides of the box will do fine.
We will be sealing the joints with silicone and sealing the wood with any good exterior wood sealant to keep the wood from rotting and water from getting inside.
The front of the box will be a piece of UV proof plexiglas. UV proof to keep as clear as possible and plexiglas to keep from breaking if struck by anything. Glass can be used instead of plexiglas if you can keep it from breaking.
All this is to keep the guts of the panel (solar cells) protected from the elements. Also the size and shape of the panel will be determined by the layout and number of solar cells.
The solar cells that we are going to use are the exact same cells that are used in the commercially made panels. The money saving part is we are going to solder them together ourselves! It's not that hard!
Solar cells have a positive side and a negative side. We will be connecting (soldering) them with a flat wire called tabbing wire" from the positive to the negative side. This is connecting them in series and allows us to add the output voltage of each cell (0.5 volts) to get the desired output voltage. Example : 32 solar cells at 0.5 volts each = 16.0 volts.
Now the solar cells are going to be the most expensive part of our solar panel project, but I can help you with that...