The first DIY Solar Panel Experiment, (the one on the backyard shed) was assembled using silicone adhesive sealant. The panel was producing electricity to the moment it was disconnected from the charge controller and removed from service. A couple factors dictated the need to be dealt with quickly. First were ever expanding cracks from screw holes in the front panel. Second was an obvious warping problem with the rear panel which is where the solar cells are mounted causing about six cells to break up. Preventing further damage and hopefully salvaging most of the remaining intact cells became the order of the moment. Little did I suspect silicone adhesive sealant was one of the culprits.
The rear panel was fabricated from several acrylic pieces glued together using silicone adhesive sealant. For some reason, one glued edge pulled away and warped toward the fragile solar cells breaking six of them. Oops! Two lessons learned: 1-sometimes the bargain basement method isn’t a bargain. 2-silicone isn’t the right adhesive for the job. Future back panels will be one piece even though my original panel may have been just fine if bonded with a different adhesive sealant material.
Most types of silicone adhesive sealant have three strikes against them when used in making solar panels: 1-It has poor adhesion to acrylic or polycarbonate. 2-Once silicone cures additional silicone will not adhere to it. Discovering a gap where there shouldn’t be one means disassembling, removing all original silicone and redoing the process. Yuck! 3-The method of encapsulation I’ve been considering uses conventional silicone to seal the backside of the cells. Not too desirable when the plan was to adhere the cells to the back panel with silicone and it doesn’t stick to itself and is marginal at best adhering to acrylic. Thus a fresh challenge: finding flexible adhesive sealant products that adhere well to aluminum and acrylic or polycarbonate.
One product immediately sprung to mind. Marina job experience using 3M 5200 marine adhesive sealant makes me believe it a good candidate for the purpose. The spec sheet says aluminum may need priming for best adhesion. It also bonds well to acrylic and polycarbonate. Considering it is frequently used below waterline, I’m willing to give it a try without priming. A tube of it is in possession and will be used in at least one of the larger panels.
The second product called Lexel was found in a local hardware store. A Google search turned up a data sheet with lots of info. Bonding strength to both aluminum and acrylic or polycarbonate though possibly a bit lower than the 3M product appears quite adequate for solar panels. Lexel is also less costly, probably because it is not designed for marine use.
Either product seems suitable for bonding and sealing front and rear panels to aluminum perimeter frames. It’s tempting to clamp the front and back panels in place until adhesive cure is complete and forget about using additional means of securing the panels. Only one problem: I’m an over kill champ. So just in case the adhesive sealant lets go I want to insure neither panel can fall off.
Oh, about my ‘over kill champ’ claim. Just ask my brother. On second thought I’ll ask and if willing he may spend a little time at the keyboard explaining why I have legitimate claim to the title.
Anyone with suggestions, experience building their own solar panels or knowledge of adhesive sealant products suitable for DIY solar panels and willing to share please feel free to comment. They will be much appreciated.
