Mounting solar panel brackets to fiberglass

[JKFlipFloop]

I would like to mount some large aluminum solar panel brackets to my roof
using a similar set-up as this. One problem, I would perfer NOT to drill holes in my fiberglass top.

What would be STRONG glue/adhesive to bond aluminum to fiberglass?

I have heard ideas ranging from liquid nails, marine-tex, 2 part epoxy, jb weld, or GOOP

https://www.youtube.com/watch?v=OYkSj8zyxL0

[wincrasher]

Use 3m VHB tape type 5952. You can find it on Amazon. Apply the tape to the feet, then stick to the (clean) van roof. Cover the feet and edges completely with Dicor sealant.

That's how I mounted my panels. Took a 700 mile trip down to sunny Florida, out in the 90 degree heat, going down the highway at 70 mph, they didn't come off.

[stanw909]

I used Eterna Bond.

[markopolo]

Drill, Well Nuts, Dicor sealant here

With tape, the surface prep would have to be good and if it is a painted surface then you have to know how good that paint bond is. Here's a report of a VHB tape solar install failure: http://www.classbforum.com/forums/f5....html#post8728

My van has a painted fiberglass roof - the paint bond would not be suitable. Some paint came up when I was trying to re-position a decal.

[jeomelia]

I used 3m 5200 marine adhesive sealant fast cure and have over 10k miles since the install on my 92D190V RoadTrek. No matter what method you pick, read the mfgs install instructions and use the ocleaner and suface preperation. When I looked at 3m VHB tape I was not shure if I could get the 15 PSI presure required for install since my bracket contact area was 6 sq in.

[booster]

I was similar to Marko. I would trust the adhesives a whole lot more than the paint adhesion on the fiberglass, especially when you know that the wind load is going to flex things at least to some degree. I did wellnuts also, but wasn't happen with how runny the Dicor was. Since we have a curve, slope, of some sort where nearly all the feet went, I wanted something better at gap filling. As it turned out, the wellnuts stand proud a little under 1/32", so that gave me a nice minimum gap, also. I used PL urethane sealant which is also a fantastic adhesive to almost anything, and it has very viscous so it stays put. Put it around the wellnut thicker than needed, so it squeezed out when I tightened the bolt so perfect fill underneath and an easy "finger trowel" around the edge. I also put a bit on the screw when I put it in, and covered it when done.

I think that if you have any kind of uneven surface that would mess up perfect contact, I would stay away for the VHB tape. It is great stuff, but it needs perfect contact and application pressure.

We have been fine in 50mph winds plus highway speeds without issue in the 3 years.

[JKFlipFloop]

My van top is painted white. Did not consider that. I suppose a drill and wire brush could strip the areas I want to bond. Those rubber well nuts look promising. They are kinda like a concrete anchor, except have a rubber sleeve, interesting

[booster]

Originally Posted by JKFlipFloop

My van top is painted white. Did not consider that. I suppose a drill and wire brush could strip the areas I want to bond. Those rubber well nuts look promising. They are kinda like a concrete anchor, except have a rubber sleeve, interesting

They also make the well nuts that have expandable metal on the hold side, like the slotted pop rivets for plastic. That is what we used.

[JKFlipFloop]

can you post a link?

[jeomelia]

I had fitted (bent) the brackets so that they fit flush to the roof

[booster]

Originally Posted by JKFlipFloop

can you post a link?

McMaster-Carr

[booster]

Originally Posted by jeomelia

I had fitted (bent) the brackets so that they fit flush to the roof

As did I, it is almost a necessity on a Chevy Roadtrek roof. I used aluminum angle and would bend down on leg to alter the angle to get closer to the roof angle. The roof is often a curve and not straight, so all you can do is get closer, not perfect.

[wincrasher]

Bear in mind that on all the non-euro vans, you are going to have alot of wind loads on the panels. So keeping them tight to the roof is rather important. Also you may want to fashion some wind block vanes or gaskets to keep air from funneling under your panels. On the euro-style vans like the Promaster and Sprinter, this is not as important. The shape of the front essentially puts most of the flat roof in the slipstream and there is very little air movement up there.

[Oliver]

If you are not 100% sold on brackets, you could consider the points mentioned in this video:

Flexible Solar Panels Mounted Flat for less air drag

They argue this:

... so you don't have this:

[SiennaGuy]

Here's a review of flexible solar panels after a year using them on an RV.

http://www.youtube.com/watch?v=_mFgMfKRRLI

[wincrasher]

All these issues we told them long before they installed 'em, but they wouldn't listen. AM Solar stopped selling them for these reasons.

[Oliver]

Originally Posted by SiennaGuy

Here's a review of flexible solar panels after a year using them on an RV....

SiennaGuy - thanks for the video link on flex panels !

[Hein]

For Sprinter vans, we like mounting panels to the factory roof rails:

[SiennaGuy]

Originally Posted by Oliver

If you are not 100% sold on brackets, you could consider the points mentioned in this video:

Flexible Solar Panels Mounted Flat for less air drag

They make a big point that the Sprinter has a curved roof and have a blue arrow showing that curve. The problem is that the roof is not just curved, it has ribs. If you look closely, the flexible panels don't flex enough to match these metal ribs. As a result, they too are subject to air getting underneath them.

The panels on mounts are designed to have air flow under them without obstruction. Glued on flex panels are not. It's entirely possible that air could get scooped up and trapped in a pocket under a flex panel unless the panels are throughly caulked. Water, dirt and debris could also get stuck in one of those uncaulked pockets, possibly leading to rust.

The flexible panels have a softer plastic surface that's subject to gouging, as the Wynns showed in their video that I mentioned earlier. The rigid panels have a harder glass surface that's less likely to get gouged. It's still glass, however, and this surface can break if something severe happens to the panels.

There's no ideal solution but I tend to trust the folks at AM Solar. They have a lot more in-depth experience with both flexible and rigid panels than I do and they made the choice not to carry the flexible ones anymore.

[bigdan]

Installed a 200W panel on my Rialta .....

it`s 32" x 62 " ......did some brackets with 1" x 3" aluminum angle

glued with urethane on all the bracket length ,,,,,,,I defy anyone to remove it !

Never do holes true a roof if possible ......

I pass the wiring by the max air and toilet vent ......almost invisible !

Dan