drilling holes in bigfoot roof for solar panels

[redbarron55]

Many techniques will work.
I can't speak for the others, but mine has been from sea to shining sea, north to Canada, and south to the Gulf.
Many others can do the same. I have little concern over the solar panels as far as function, but the last thing I want to see is one of my solar panels going through the windshield of the car behind me.
What ever you do make sure you are confident in the mounting and that it will survive the heat and cold, wind and rain, gusts and idiots.

[Raspy]

For all of you who can't get past the idea that bolts won't leak, remember, bolts are used on the bottom of boats, below the water line. That's how rudder gudgeons, heat exchangers brackets, bobstay brackets, engine mounts, through hull flanges, etc are bolted on.

One of the best sealant/adhesives for sealing these is 3M 5200. It is used below the water line.

And 5200 has a stronger bond to fiberglass than the fiberglass itself. If a part is simply pried off the fiberglass surface, it will rip a chunk of the fiberglass off with it.

So, if you really want to make sure something doesn't simply fly off the roof, or leak in the rain, bolt your part down, with the bolts facing up, nut on top, fender washer below, and use 5200 between the part and the roof, and where the bolt passes through. The bond is stronger than the roof itself. It will not leak even if you turn it upside down and use it as a boat. At that point, the bolt is redundant, but reassuring, and it holds everything in place until the adhesive sets up.

This not rocket science, and mariners have a much larger need to keep water out than RVers.

[JPr]

Raspy's got it.

[getaway1]

Hi
For what it's worth the awning rail on my Trillium was bolted on using butyl tape nearly 40 years ago and has no leaks. Your solar panel will be affected by the wind and vibration on a trip. This action over time will no doubt cause rivets to move and wear the hole some. I would suggest you use stainless steel bolts & nuts (no rust staining) with a rubber sealing washer + sealant too. Using bolts allows you to tighten them in the future or remove the panel easily if need be . Duane

[redbarron55]

I have no problem with bolts headed up with the heads on the inside, but I like to see that they are still there and they don't really bother me being on the inside.
Bolts upside down are better than a little scotch tape and spit.
I really don't understand the problem with drilling a hole in the fiberglass as the factory has already drilled a hundred or so and did it with much less attention to detail sealing that you would on just a few.
The leaks that cause problems were installed when the trailer was made and from failure to maintain the trailer.

[stevebaz]

Originally Posted by JPr

I didn't, but that's a good idea.

When using metal rivets you have to be careful to stop apply pressure to the rivet gun just before the rivet breaks. Other wise it might pull though the fiberglass.

do what scamp use to do pull it up tight and cut the shank right at the head trapping the shank under tension. much harder to get a leak through the rivet.

[redbarron55]

My bet is that Scamp is using pneumatic rivet pullers like everyone else in volume production using Pop rivets.
The pop rivet has a small nick in the mandrel stem engineered to break when the pulling tension has been met.
If the rivets were snipped off then the mandrels would actually poke out further.

[minke]

Originally Posted by Anthony B

I'm about to do this too my bigfoot. The problem it Bigfoots have 1" of foam under the roof. So if you want to throughbolt you have to tear your roof apart. Not gonna happen. You can use rivnuts or well nuts of you can do it marine style. Oversize hole. Hollow out the foam behind it and then fill with epoxy (good epoxy) and then then drill a hole in that and screw into it with your stainless metal screw. Its effectively a big epoxy nut that is sealed. you want to use an adhesive sealant between the roof and your braket as well, cover the screw head.

I'm not going to be that fussy. I'm going to drill a hole at the size of the minor diameter of the #14 stainless metal screw (two per bracket). and then hollow out the foam a little bit. I'm then going to fill it with epoxy and apply sealant and wet screw it. The epoxy will solidify around the screw which will be held tight by the thin glass shell as it sets and it will provide extra holding power. I'm going to use Lexel which is similar to "through the roof".

potential issue is that there is a gap between the foam and the roof which allows the epoxy to run laterally. I'm going to make the hole in the foam shallow (about 1/4") and hope that the metal screws bite into the foam enough to suck it up to the skin and make the epoxy bond to the back side.

By the way, I just redid a roof vent on the bigfoot and they didn't even remove the gelcoat from the edge of the holes and they all had spider web cracks same with the sloppy cut out. They were not too concerned about just slapping it up there. We DIYs are way more fussy than professional installers.

From This Old Boat second edition by Don Casey.

[Raspy]

Originally Posted by minke

From This Old Boat second edition by Don Casey.

Do any fiberglass trailers have core construction in the roof, similar to the included diagram? I haven't seen it. Oliver's have it in certain spots, but not in the roof.

[minke]

Originally Posted by Raspy

Do any fiberglass trailers have core construction in the roof, similar to the included diagram? I haven't seen it. Oliver's have it in certain spots, but not in the roof.

I thought that Bigfeet were constructed that way. Am I mistaken?

[Rick L. Harrison]

Use the 3M VHB tape, Watch the demo videos on the stuff. I am the 2nd owner of a 25B25FB 30th year anniversary edition Bigfoot Love it HATE THE HOLES PUT IN THE ROOF FOR SOLAR. I am going to repair the holes / gel coat and use 3M VHB holes are not needed with the VHB tape. I hope when I am done you will never know they were there.

Put the tape on long aluminum angle, with hinges and supports then you can tilt them to the sun.????????

[ZachO]

As you can see everyone has an opinion.

I’ll sum up what I think of these discussions and leave it at that.

Everyone has their anecdote. There’s the saying that the plural of anecdote is not data. I’ve also heard it said that no, it’s not data. But many anecdotes form a hypothesis, which you then test.

Since we’re not going to do a true experiment here, take people’s experience for what it’s worth. One person’s experience. “I never wore a seatbelt my whole life and I’m fine”, etc.

Obviously you can get away with just VHB. Obviously that type installation has failed, no matter how many people chime in saying they’ve had no problems.

IF installed correctly, VHB will not fail. But the fiberglass underneath it might.

If you tighten rivets too much they’ll pull through the fiberglass...so what’s to stop that in a wind gust?

Like I’ve said, mine are on with VHB + Eternabond. “I’ve had no problems”. All the same I’m going to bolt one front and one rear corner sooner or later.

[redbarron55]

If pulling the pop rivet to break the mandrel pulls the shop head through the fiberglass the hole was too large, the fiberglass to shredded by drilling or something else is wrong and the rivet is not going to hold anyway.
When I was at the factory I never saw anyone clipping the ends off the mandrels.
They look like they are clipped because they are weakened at the intended break point and have that appearance.
When the bulb is expanded by pulling the mandrel it the bulge moves down the length of the hollow rivet until it hits the constriction of the hole and the pressure stops the head and the tension pulling it down breaks the mandrel when it's pull strength is reached.
If you cannot set the rivet then the material is too soft or the hole is too big.
In actual use sometimes for soft material a washer of the proper size is placed over the shank on the back side and this is used to provide the needed constriction to pull the rivet.

[wallnut1234]

quick update I ended up using vhb tape + bulb rivets + dicor sealant, I'm heading out for a road trip in the rockies in 1 or 2 days, we'll see if it holds up

[ZachO]

It will.


Glad you got it installed.

[redbarron55]

I think you will be fine. The mechanical fasteners will keep the VHB from starting to peel and the VHB will provide plenty of strength to keep the fasteners from getting loose.
Good job!

[wallnut1234]

so I rode from montreal to banff, ran into some pretty intense wind along the way, let me tell you I was peeking at my mirrors often to see if those suckers were still there and they held up so far. Man I love this solar setup, I've been running it for more than 1 week, I was at a campground with hookups and dident even bother pluging in.

[snuffy2]

Years ago I installed windows in an Corsair F24MK1 sailboat, all I used was 3mVHB. We sailed that boat a lot so the hull is constantantly flexing. We never had a leak or anything come loose. When we sold the boat it went to the northeast to rougher seas and colder weather, windows are still there. They use this stuff on skyscraper windows.

The one time I've had to remove VHB tape I cut the straw of a can od WD-40 inserted and sprayed while applying tension to remove, it did come off with no damage. I wouldn't hesitate to sue it just make sure it's properly prepped and remember, once you stick it it's stuck.

My two cents

[Nealster]

Has anyone thought about heat transfer? If I glue a black panel to my white roof the the sun's heat will warm up the trailer. On the other hand if the panel is elevated with brackets wind will push any heat away that is absorbed by the panels from the sun. For this simple reason I would go with the bolted on brackets.

[Flydog]

Agree