Solar mounting with VHB tape, any last thoughts?

[Rensho]

I'm about to mount a 265w panel on my 144" in the forward position.

Panel is 64.5" x 38.5". The fit is nice lengthwise as the panel just clears the 2 outside ribs on the roof.

I plan to use (6) 12" aluminum 1.5" L brackets, 3 on each side of the panel. I will use 12"x1" of VHB 5952 under each bracket. I will then dicor the perimeter of the feet.

 

[hein]

Sounds bomber. Would be a little better to have VHB on the full width of the 1 1/2 angle so there is no space for water/moisture to accumulate behind the sealant. Moisture can compromise the VHB bond over time.

Don't plan to ever remove those angles from the roof. We do have more 8020 brackets if anyone want's to go that route. Or a row of 8 of these per side with some angle brackets could work.

 

[Aqua Puttana]

I've seen Dicor alone used to mount the brackets for RV roof vent over covers. They hold without failure. The brackets are pretty difficult to remove if that becomes necessary.

The Dicor seals very well and will add bonding strength of itself. Between the VHB tape and the Dicor it sounds like a decent plan to me.

I assume the aluminum is anodized or otherwise protected. If not, corrosion can creep in over time and may affect the bond in some environments.

Please post pictures of the completed install.

vic

 

[calbiker]

I used VHB4950 with 2" angle Al. It's been solid for 8 years. Each foot has 6" x 4" = 24 sq in of 4950 contact with a fiberglass roof.

 

[bstory]

Sounds like you got it sorted out. The only thing I'd add is a reminder to clean the surface with rubbing alcohol as directed by 3M and if it is at all cool when you do it, find some way to keep the heat on the aluminum-VHB bond for 15-20 minutes. If you can apply pressure too that's more to the good, but the only way we could think of doing that was to stand on each bracket as it was done and even jump up and down on it so there was even higher pressure (albeit intermittent) for a few seconds.

Our panels have been on the van with no issues for over 2 years and 2 cross country trips.

 

[israndy]

I did not go rigid with my panels, I got the fiberglass mounted ones and then used 3M 777 spray adhesive. Not sure how long it will last but I am one year in w/o issue. Since I didn't wanna take the paint up when I need to replace the panels or upgrade I used that spray film, like a clear bra film for your hood, but on the roof, before the adhesive. Will be interesting to see how that works out. The film trying to protect the paint, the adhesive trying to stick everything to everything... Really shocked I have yet to hear my panels blowing against the back of the car as I drive down the highway. Haven't plugged in the RV in over a year...

-Randy

 

[ehallspqr]

AM Solar in Oregon installed my solar panels and used 3m tape on the brackets for their installations. I was concerned at first but they assured me that after years and hundreds of installs they have not had anyone complain about a failure. Mine is going on a year and looks fine. They also sealed the bracket foot with dicor. As mentioned prep the surface well.

 

[Rensho]

Thanks all for the replies. I did see the AM solar brackets, as well as a few other attempts searching around.

I've riveted some smaller brackets under the panel today and will clean and mount the panel tomorrow.

Thanks for the reminders of proper temp and pressure.

Wish I had roof rails and just bolt them on! ;-)

 

[Rensho]

I ended up finishing the install through out a few days. Not a tough job, but all the little stuff adds up and takes time/days.

The VHB worked incredibly well. The 6 12" mounting feet might be able to lift the van, or at least heavily bulge the roof trying to do so.
I went with an ABS 4x4" junction box with a 1" hole through the roof. Waterproof strain relief for the 2 solar cables from panel. Dicor sealing to roof.
I slightly angled the panel for water run off.

Learned lessons:

--12" feet make it very tough to reach around back to install nuts, especially with only about 1.5" panel to roof clearance. 6-9" would have been better, or drill the bolt hole nowhere near the 12" center.
--Next time I'd just buy 6-8 of the AM solar feet and install those. No thinking involved and fewer gotchas.
--Fully attach extension cables and zipties before laying panel on roof. Trying to attach cable management and zipties afterwards is a pain and maybe dangerous (high roof).

 

[hein]

VHB for the win!

Pads are fixed to the board with VHB.