Advise on installing solar panels, what fastener to use?

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cupe873

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Hi all
I am installing solar panels on my 2006 Itasca Ellipse motorhome. I read John's write up on "Zamp solar panels installed" Great write up. My problem is my roof does have some areas where the top material has come loose. Not where I want to put the solar panels but in other areas. My worry is that a lot of the holding power is just the caulking to the roof. I can not afford to replace the roof right now. I was thinking about using short Jack nuts or well nuts. I would like something that has more holding power then pan head screws. Am I being silly or would pan head screws work just as well
 
Two ideas for you.

If you have areas of the Filon becoming separated from the Luan substrate you can drill small holes and inject epoxy under the Filon. Place weights on the area and let the epoxy cure overnight. Problem solved. If you are interested in doing this, let me know. Then you can use self leveling sealant and truss or pan head fasteners for the brackets. The sealant probably does 99% of the holding power.

Call or email Winnebago Owner Relations and ask them for a structural drawing of the roof. You can place aluminum square tubing or flat bar from roof beam to roof beam and install the panels on the square tube or flat bars (I would drill and tap when mounting the panel brackets.) Onlinemetals.com has a vast assortment of metal and even plastics now.
 
I have my 5 panels attached with VHB and they are as solid as the day I put them up there. Having said that I have the same roof as you that also has some delam bubbles in it and (still) plan to do what John is suggesting with epoxy filler. It “shouldn’t” a big deal.. I was looking at using sandbags and working on a few SqFt at Al rime
 
Drilling a bunch of small holes and injecting special epoxy* is time consuming so working on a small area (maybe 4 to 6 sq ft) at a time is a good plan. The results are however quite good and worth the time and expense (*WEST has special epoxy designed for delam mitigation.)
 
Anodized aluminum is the metal that is used on most components involved in the installation of solar panels. It is favorable due to its ability to resist corrosion and light. Brass or bronze bolts and nuts and stainless steel rods are used for their reliability and hard-wearing capabilities.
 
Brass fasteners are for specialty use, its tensile strength is fairly low. They would be used mostly for electrical connections where low electrical resistance is a requirement. I'm familiar with bronze being used for certain marine applications due to being highly corrosion resistant and relatively strong, more so than brass. I don't recall any brass being used in our former coach.

Anodized aluminum is highly desirable but I don't believe it's being used for very many applications due to manufacturing expense.

My choice for structural applications in this situation (fastening solar panels or anything for that matter) to an RV roof is 300 series stainless steel fasteners. On our 40' ketch, practically every fastener I used was 316 stainless steel.
 
The frame on all my panels are extruded anodized aluminum and they are doing OK, but all mounting hardware is stainless. As someone who camps extensively on the beach and constantly fighting corrosion (maybe worse than a allot of boats due to a constant on-shore breeze pushing breaking wave mist across the campsite, and I’m here to tell ya that brass and my campsite don’t mix. At all..

I’ve gone so far as to match as many Winne steel screws (painted or not) as I can and replace with an exact SS match. The painted ones are replaced with painted SS as even those that are painted will rust through.

As mentioned, all of my Stainless Solar feet are attached to the roof with VHB, and that connection is sealed from the weather with my new favorite goo: NUFLEX 311 Silicone.
 
I was on the same mission to replace many of the steel fasteners on our former Horizon with stainless steel. Your beach camping situation with blowing sal****er mist sounds like a test environment for evaluating various metals in a hostile environment :ROFLMAO:
 
John Canfield said:
I was on the same mission to replace many of the steel fasteners on our former Horizon with stainless steel. Your beach camping situation with blowing sal****er mist sounds like a test environment for evaluating various metals in a hostile environment :ROFLMAO:
Click to expand...
it’s ridiculous I tell ya…
 
I also use stainless steel fasteners for anything exposed to the weather. One situation that can be problematic is stainless steel fasteners that are threaded into aluminum. These fasteners become almost impossible to remove after a period of time. A boating friend told me that brass would be a better option in this case.
 
Use a small plastic insulator washer between the aluminum and the stainless steel if you go that route. Then just caulk right across the fastener heads with some dicor or whatever you use under the support brackets. These are a sample, most hardware stores sell a similar type.


I will add that hardware store stainless steel hardware is mostly 18-8, which is barely what is considered to be stainless. So we call the fasteners "Stain-Less". But most do create some rust residue over time if you are in a high humidity area with salt air.

Other type fasteners are rated at 304 or 316. The 316 is normally the best of the the three grades. But they are rarely found in big box or hardware stores. Pan heads are really hard to find in 316, which would be the preferred fastener. There are lumberyards that sells deck screws in 316, and will work even though they are not panheads.
 
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Tom_M said:
I also use stainless steel fasteners for anything exposed to the weather. One situation that can be problematic is stainless steel fasteners that are threaded into aluminum. These fasteners become almost impossible to remove after a period of time. A boating friend told me that brass would be a better option in this case.
Click to expand...
On my sailboat I used an anti-seize compound on SS fasteners in aluminum. Even at that sometimes the fastener would seize but applying heat would free it.
Tulecreeper said:
Because of the word the 4-letter word the *** spell out in the middle of the word...sal-t-w-a-t-er. Yeah, the bot is oversensitive.
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Ah, got it. You must have a dirty mind :D
 
John Canfield said:
On my sailboat I used an anti-seize compound on SS fasteners in aluminum. Even at that sometimes the fastener would seize but applying heat would free it.

Ah, got it. You must have a dirty mind :D
Click to expand...
Yeah, that and I saw it happen on here several months ago when I typed the word wris****ch.
 
I have always recommended simple, but good quality toggle bolts to our customers and no one has ever reported any problems with their devices coming loose.

We do a lot of product testing, and I wanted to come up with a simple way to install, remove and reinstall our products from the roof - multiple times - without having to drill new holes each time. We found that, if we put a glob of Dicor on the wings of the toggle bolts (arrows) the wings would stay attached to the under-side of the roof when we removed the bolts. Then as long as we were careful when reinstalling the bolts (i.e. don't push down too hard) the wings acted as hard-mounted nuts.

A lot of people rely solely on VHB (or similar) tape to secure their panels to the roof. That's fine with fiberglass roofs, but don't do it with "rubber" roofs as they are simply glued to a substrate. If you're going to use VHB tape, I would recommend putting a bead of Dicor (or similar) around the edges of the tape. It will help prevent water from getting into the tape from the sides.

Kev
 

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Kevin Means said:
I have always recommended simple, but good quality toggle bolts to our customers and no one has ever reported any problems with their devices coming loose.

We do a lot of product testing, and I wanted to come up with a simple way to install, remove and reinstall our products from the roof - multiple times - without having to drill new holes each time. We found that, if we put a glob of Dicor on the wings of the toggle bolts (arrows) the wings would stay attached to the under-side of the roof when we removed the bolts. Then as long as we were careful when reinstalling the bolts (i.e. don't push down too hard) the wings acted as hard-mounted nuts.

A lot of people rely solely on VHB (or similar) tape to secure their panels to the roof. That's fine with fiberglass roofs, but don't do it with "rubber" roofs as they are simply glued to a substrate. If you're going to use VHB tape, I would recommend putting a bead of Dicor (or similar) around the edges of the tape. It will help prevent water from getting into the tape from the sides.

Kev
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The problem with toggle bolts is that you have to drill a hole 2.5 to 3 times bigger than the screw that is attached to the "wings". When drilling through a panel - especially on a roof - you definitely don't want a hole any bigger than absolutely necessary. Even if you can apply a patch afterward, do you really want a 3/4" hole when you only need a 1/4" screw?
 
Kevin Means said:
I have always recommended simple, but good quality toggle bolts to our customers and no one has ever reported any problems with their devices coming loose.
Kev
Click to expand...
Great idea Kev! I never would have thought of using toggle bolts on the roof but that certainly meets the requirement of being reused. As a rule, toggle bolts aren't on my list of fasteners due to the hole size required as previously mentioned but I do use them sometimes.
 
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