Kernwig's Solar Build

[MyronL]

I just now found your original posting and it certainly got my attention. Most regrettable, to say the least. Feeling relieved I only used Eternabond with my solar work as a small patch to waterproof-over my bolted corner brackets. If I get into Utah, or Arizona, or everywhere it is intolerably hot this summer I certainly will be watching how it performs.

[kernwig]

Originally Posted by MVA

From your photos, it appears that the tape was still mostly adhered to the trailer roof, but appears to have curled first, or failed at the tape - flexible panel interface. The front edge appears to be different in that that seam failure may have been the roof-tape interface (?). Is it clearer when you look at it as opposed to the photos?

My wife is traveling without me, so all I have is photos... but higher quality than the forum. It looks to me like the leading edge developed a gap, and then the panel was ripped up from there. In that lift action from the wind, the contact to the rough panel frame material would likely be weaker than to the fiberglass.

Originally Posted by rubicon327

It seems almost unbelievable that it would come up with all that tape. I know this is probably a remote possibility but any chance it might have been stolen?

It definitely came off on the highway; sound like someone from behind witnessed it and flagged down the wife.

A person would disconnect or cut the wires, not tear if all along the roof line. A thief would also have a much easier time cutting the tape than tearing it off!

I expect it was many many miles of wind lift effect to peel about the first half up, and then the rest all tore away very quickly. Bummer too - that was the preferred panel: higher wattage, rarely shadowed, and covering the old TV antenna hole. If it were the rear that came off, there would be no rush to replace it.

[Brian B-P]

It does look like the tape failed at the front, then the airflow peeled the panel off of the roof. Peeling is the usual failure mode for flexible things pulled at from one edge; you can have adhesive that can withstand tons of force if pulled straight out that can be peeled with a tiny fraction of that force. Think of hook-and-loop fastener strips (such as Velcro) - you can easily grab one end and peel it apart, but pull at the whole strip at once and it can take a lot of force.

I've only used Eternabond once, and it worked well in that application... which was sealing a seam, as it is intended to be used. It's tenaciously sticky stuff, but I believe it is intended for sealing, not as a structural adhesive.

Was there nothing between the panel and the roof, just the tape over the edges? I think a more typical and secure installation would be to use double-sided tape (such as the famous/infamous 3M VHB) on the back of the panel to hold it down, then tape over the edge to seal it.

[TahoeJoe]

That's a bummer for you but hey glad that no one was hurt and there wasn't any other major damage. I'm about to start my own solar install, and I'm putting on framed rigid panels and not the flexible, but still I have been trying to decide whether to use screws, or just the eternabond method. Just knowing about this accident of yours ticks me a little closer to using screws...

[Brian B-P]

Originally Posted by TahoeJoe

... I have been trying to decide whether to use screws, or just the eternabond method. Just knowing about this accident of yours ticks me a little closer to using screws...

A third alternative would be to use a more appropriate adhesive.

[Chris R]

Originally Posted by TahoeJoe

That's a bummer for you but hey glad that no one was hurt and there wasn't any other major damage. I'm about to start my own solar install, and I'm putting on framed rigid panels and not the flexible, but still I have been trying to decide whether to use screws, or just the eternabond method. Just knowing about this accident of yours ticks me a little closer to using screws...

Please do not use screws, they will not hold. Bolts with backing plate/washer. Or appropriate adhesive.

[TahoeJoe]

Originally Posted by Chris R

Please do not use screws, they will not hold. Bolts with backing plate/washer. Or appropriate adhesive.

I misspoke, and said "screws" when I meant metal fasteners as opposed to adhesive/tape only. I'll be using bolts and washers, most likely these:
https://www.renogy.com/2-sets-of-sol...cket-set-of-4/

[Centex]

Originally Posted by TahoeJoe

I misspoke, and said "screws" when I meant metal fasteners as opposed to adhesive/tape only. I'll be using bolts and washers, most likely these:
https://www.renogy.com/2-sets-of-sol...cket-set-of-4/

Please note that the linked Renology brackets are provided with screws, not bolts, for the bracket>trailer interface. Sure, you can make your own substitution, but be attentive to the diameter of the hole in the bracket and how close it is to the edges - eccentric enlargement of an existing hole can be 'sporting' to say the least.

Just for your consideration, Have Fun!

[TahoeJoe]

Originally Posted by Centex

Please note that the linked Renology brackets are provided with screws, not bolts, for the bracket>trailer interface. Sure, you can make your own substitution, but be attentive to the diameter of the hole in the bracket and how close it is to the edges - eccentric enlargement of an existing hole can be 'sporting' to say the least.

Just for your consideration, Have Fun!

Ah yes, I see that now...I wonder what would be the best type of bolt fastener to use for a fiberglass roof?

[Perry Butler]

Originally Posted by Brian B-P

I think a more typical and secure installation would be to use double-sided tape (such as the famous/infamous 3M VHB) on the back of the panel to hold it down, then tape over the edge to seal it.

Finished adding three 100 watt Renogy panels to our 5.0 that already had the ETI installed 170 watt panel. AM solar uses four brackets per panel, with each bracket having 2 1/2 square inches of 3M VHB tape and that's for large panels. They claimed they've never had a panel blow off. I used 6-12 square inches per bracket after prepping and cleaning the fiberglass. I can't imagine these panels ever coming loose.

__________________________________

Two weeks from today we leave for the infamous "Pelikan/Kazeck Family Campout" and then for the following 10 days will be camping in shady sites, so hopefully with 465 watts the portable stays underneath the bedroom steps.

I'll try to finish getting pictures and write up an install in the next couple of weeks before we leave on our camping trip.

Enjoy,

Perry

[TahoeJoe]

Originally Posted by Perryb67

Finished adding three 100 watt Renogy panels to our 5.0 that already had the ETI installed 170 watt panel. AM solar uses four brackets per panel, with each bracket having 2 1/2 square inches of 3M VHB tape and that's for large panels. They claimed they've never had a panel blow off. I used 6-12 square inches per bracket after prepping and cleaning the fiberglass. I can't imagine these panels every coming loose.

__________________________________

Two weeks from today we leave for the infamous "Pelikan/Kazeck Family Campout" and then for the following 10 days will be camping in shady sites, so hopefully with 465 watts the portable stays underneath the bedroom steps.

I'll try to finish getting pictures and write up an install in the next couple of weeks before we leave on our camping trip.

Enjoy,

Perry

I've been following your posts and look forward to the full write up...where I'm at now is that I was either going to go the route you just did, or use metal fasteners of some kind...

[Brian B-P]

For those who like to be technically correct, what we normally (and correctly) call "bolts" are also correctly known as hex cap screws.

Screws come with various types of threads. The linked Renogy brackets are supplied with self-drilling self-tapping cap screws because Renogy assumes that they will be driven into wood (or possibly aluminum) roof structure. Without that structure or a substitute, mounting to the shell of an Escape with screws calls for machine cap screws (a.k.a. bolts) which go through the roof and engage a nut on the other side. You could also bond a block to the inside of the shell and use the supplied self-tapping screws into it as if it were a conventional RV roof.

Self-tapping and wood screw sizes are identified (in North America) by a numbered scale, and the Renogy screws are relatively big #11. Those are 0.203" (or 13/64") in diameter, so the bracket holes will be at least slightly larger than that. If you are using inch-sized machine screws (bolts), a 3/16" or M5 size will fit that hole, and with appropriate washers that's more than strong enough. It wouldn't take much enlargement to go for 1/4" or M6, but they're not needed.

[TahoeJoe]

Originally Posted by Brian B-P

For those who like to be technically correct, what we normally (and correctly) call "bolts" are also correctly known as hex cap screws.

Screws come with various types of threads. The linked Renogy brackets are supplied with self-drilling self-tapping cap screws because Renogy assumes that they will be driven into wood (or possibly aluminum) roof structure. Without that structure or a substitute, mounting to the shell of an Escape with screws calls for machine cap screws (a.k.a. bolts) which go through the roof and engage a nut on the other side. You could also bond a block to the inside of the shell and use the supplied self-tapping screws into it as if it were a conventional RV roof.

Self-tapping and wood screw sizes are identified (in North America) by a numbered scale, and the Renogy screws are relatively big #11. Those are 0.203" (or 13/64") in diameter, so the bracket holes will be at least slightly larger than that. If you are using inch-sized machine screws (bolts), a 3/16" or M5 size will fit that hole, and with appropriate washers that's more than strong enough. It wouldn't take much enlargement to go for 1/4" or M6, but they're not needed.

Thanks for this clarification and info, it's a big help for someone like me with limited knowledge in this area...

[kernwig]

As I recall from reading about multiple installs in this forum, most folks used _either_ Eternabond or VHB. I was thinking the VHB route at first, but was concerned that:

1. I'd attach the VHB to the edge of the panel, flip it over, and some bit would stick to the roof before the panel was in position and never let go!
2. Someday the panel would fail and I wouldn't be able to remove it!

Since the Eternabond camp had years of success, I went that way. Seemed to would hold, but not to the point that I can't remove it when I want to.

The trailer is home now and the rear panel is dusty, but the tape look exactly how it was when installed. It's the smaller one and largely shielded by the air conditioner.

On inspection, I'm sticking with my theory about how the front peeled off.
Based on discussions here, I'm thinking:

1. Eternabond still for sides and rear.
2. Strip if VHB under the leading edge (placed after rear is taped into place).
3. Two stepped layers of Eternabond over the leading edge.
4. Also, retro rear panel with a second stepped layer of Eternabond over leading edge.

[dstreight]

The way I attached mine: VHB an 80/20 (8020.net) that the solar panels get screwed to. That way, if panels need to be swapped out in the future for same/different size (the 80/20 channel provides much versatility regarding different size panels, etc. downstream compared to typical one position SS brackets...) it doesn't involve dislodging the VHB bond.

Also, when using VHB in an exterior application such as this, I go around the perimeter of the two substrates (fiberglass and anodized aluminum in my example) with a bead of 3M 5200 or similar, to help prevent water ingress to the VHB tape.

So far, and granted its been less than 2-years since installing our roof panels as described above, they are holding tight and secure.

[TahoeJoe]

Originally Posted by dstreight

The way I attached mine: VHB an 80/20 (8020.net) that the solar panels get screwed to. That way, if panels need to be swapped out in the future for same/different size (the 80/20 channel provides much versatility regarding different size panels, etc. downstream compared to typical one position SS brackets...) it doesn't involve dislodging the VHB bond.

Also, when using VHB in an exterior application such as this, I go around the perimeter of the two substrates (fiberglass and anodized aluminum in my example) with a bead of 3M 5200 or similar, to help prevent water ingress to the VHB tape.

So far, and granted its been less than 2-years since installing our roof panels as described above, they are holding tight and secure.

Thanks for this, and did you also put something like Dicor on top of it all?

I asked ETI about using fasteners, and they said that they use M10 hex-head cap screws (yes, bolts) with washers and lock nuts. And this: "It is important to note when installing the solar panels after market condensation will form on the inside of the trailer where the bolts and washers stick through the headliner, to avoid this add more insulation over top of the nut and washer to keep the coolness out."

I'm not crazy about having all that hardware coming through my beautiful white ceiling and also having to worry about condensation...

I also confirmed with AM Solar that they recommend using at least 91% alcohol as the cleaner, and their method uses only 2.5 inches of tape (as Perry mentioned). And this: "Fiberglass roofs – We have been using a type of 3M double-sided tape on our mounts since the mid 1990’s, and we have never lost a panel. As long as the tape is properly installed on a clean surface at the correct temperature, it will hold. As an added level of protection, we use a layer of Dicor self-leveling sealant around the entire perimeter of the mount, and cover the screw holes/heads as well. The sealant protects the tape and any potential roof penetrations from water intrusion and decay."

My Renogy mounts can use closer to 4" of tape, so I'm growing more confident in the adhesive method, knowing to be extra careful about the cleaning of the surfaces...

[dstreight]

I have used 3M VHB tape for a variety of applications over the past dozen or so years. Getting the proper VHB type matched for the two surfaces to be bonded is key along with proper surface prep as mentioned above.

Here's a link to the recommended surface prep procedure for VHB tape from 3M: https://www.3m.com/3M/en_US/vhb-tape...ep1surfaceprep

Also be aware, just like many adhesives, full cure & full strength of the VHB tape bond takes about 72-hours depending upon ambient temperature and humidity level.

I have successfully removed VHB tape from two bonded surfaces, well after the 72-hour cure period, using a length of piano wire wrapped around two wood dowels to guillotine the tape from one of the bonded surfaces. Coincidentally, I had to do that today apart of a removable exterior table top project I've been working on for the 15A.

[richm]

Originally Posted by dstreight

The way I attached mine: VHB an 80/20 (8020.net) that the solar panels get screwed to. ... So far, and granted its been less than 2-years since installing our roof panels as described above, they are holding tight and secure.

Neat! I'm curious about the effects of vibration/forces on 80/20 fasteners. Did they need any re-tightening after installation?

[dstreight]

I typically use Loctite thread sealant commensurate with the severity of vibration, etc. Loctite 222 or 242 is a very good thread locker that still allows easy unthreading if/when.

Having said that, I did not use Loctite on the fasteners I used to attach the brackets that hold the solar panels to the 80/20 profiles as I am not quite done with the project (done enough to keep using it but I'd like to disassemble and cut the corners off the SS brackets for a cleaner more finished look). And the 1/4-20 SS button head cap screws with SS flat washers underneath have stayed tight all year.

[Brian B-P]

Originally Posted by TahoeJoe

I asked ETI about using fasteners, and they said that they use M10 hex-head cap screws...

An M10 bolt has a shank 10 mm in diameter; used properly, one of them could hold the weight of the entire trailer. I suspect that someone at ETI meant that the bolts have a 10 mm hex head, and they are likely M6 bolts... about the same as a 1/4" bolt.

Originally Posted by TahoeJoe

... hex-head cap screws (yes, bolts)