Here is what I did with my 16' Airstream. I custom designed and made the bracket out of 1.5 x 1/8, 3 x 1/8 aluminum angle. Then the bottom bracket is mounted on roof with 3M VHB tape, then sealed with Sikaflex sealant. I am very happy with the brackets as they allow me to lose 2 nuts then lift the panel for cleaning. Also the brackets are hidden under the panel so the installation looks very clean.
I few comments I want to make on VHB tape approach.
- My custom made bracket has 3x2" bonding surface with roof, more than double most of the off-shelf ones. I feel very comfortable with the strength of them.
- 3M 4950 VHB takes tremendous dynamic stress, but far less static stress. So make sure the install does not put long lasting stress on them. This include how you design your fasteners on the bracket,
- Surface prep is super important. I used alcohol to clean both bonding surfaces, and waited for the surface to dry
. You also need to seal the contact area to protect the VHB tape.
- The roof aluminum sheet is very soft, so unless you can put nuts with washers on the other side the sheeting, the VHB tape will offer stronger install. I would not use rivets or sheet screws at all - It's not about drilling holes on roof, it's just that with that soft aluminum sheeting, screws will not be able to have a strong bite into the metal.
- I have watched many
youtube videos on how people install panels on Airstream using VHB tape. The most important lesson I learnt from them is. Never drive behind an RV with Solar Panel on them.
There are people really should not be install solar panels on vehicle that moves @60mph.