VHB Purpose, Price, and Alternatives?

[12VoltInstalls]

seems that polyurethane adhesive is a very durable and significantly less expensive option for the scale of my project.

polyurethane adhesive caulking is ridiculously strong. Air-moisture curing polyurethane caulking is more durable and tough in the elements and Polyurethane construction

 

[Browneye]

More FUD. Dear lord...

Here's what I'm picturing:

It's all just in your little head. You can be the solar panel karen. LOL

 

[A.Justice]

More FUD. Dear lord...

It's all just in your little head. You can be the solar panel karen. LOL

I'll be the guy that throws a couple of screws in for safety. You guys can all roll the dice with that tape. It's probably fine 99.9% of the time, but I'm not risking that 0.01% over a few cents worth of hardware. It just seems like a no-brainer to add screws or bolts, and / or a tether.

Eventually somebody's going to have a problem with it and there's going to be an accident. I can guarantee you that not everybody who uses it is prepping the surfaces and installing it properly, maybe most of you guys are, but that's not everyone. I'd also like to know what a decade of direct sun, heating, freezing, and the thermal expansion of different materials that it bonds, does to it's adhesive properties; I'm sure it doesn't help them.

 

[Browneye]

Agreed. Some common sense after all.
And why I put some screws in long mounting struts. There's no way I want to lose a panel on the hiway. I'm just not one to horriblize. I'm way too practical for that.

 

[A.Justice]

Agreed. Some common sense after all.
And why I put some screws in long mounting struts. There's no way I want to lose a panel on the hiway. I'm just not one to horriblize. I'm way too practical for that.

I've had enough worst case scenarios happen to me to expect them. If it can go wrong, it eventually will.

 

[Browneye]

Uncle murphy.

 

[curiouscarbon]

paging murphyguy!

 

[A.Justice]

paging murphyguy!

He would probably agree with the redundancy. ?

 

[jberger]

Since this topic seems to generate so much debate, I asked 3M directly about the suitability of VHB for Solar Panel Mounting applications on Recreational Vehicles or Travel Trailers that had a Metal or Fiberglass roof. I specifically mentioned that I was NOT asking about membrane roofing like EPO, Rubber, etc.

Please see the attached response, where they will not recommend VHB for exterior vehicle application, as they are not wind tunnel tested.

 

[curiouscarbon]

Since this topic seems to generate so much debate, I asked 3M directly about the suitability of VHB for Solar Panel Mounting applications on Recreational Vehicles or Travel Trailers that had a Metal or Fiberglass roof. I specifically mentioned that I was NOT asking about membrane roofing like EPO, Rubber, etc.

Please see the attached response, where they will not recommend VHB for exterior vehicle application, as they are not wind tunnel tested.

thank you!

 

[Browneye]

Since this topic seems to generate so much debate, I asked 3M directly about the suitability of VHB for Solar Panel Mounting applications on Recreational Vehicles or Travel Trailers that had a Metal or Fiberglass roof. I specifically mentioned that I was NOT asking about membrane roofing like EPO, Rubber, etc.

Please see the attached response, where they will not recommend VHB for exterior vehicle application, as they are not wind tunnel tested.

This is common knowledge, easy to find elsewhere as well. It's their legalese CYA statement. Use it at your own risk.

But look, they even reference installers and that they're aware it's used for that application. That is EXACTLY why we're discussing it HERE for DIY, right? How to do it RIGHT? I even referenced a professional installer that has been using it for YEARS.

I'm not liable either. If you glue your panels on and they blow off that's on you, sorry. ?

 

[12VoltInstalls]

asked 3M directly about the suitability of VHB for Solar Panel Mounting applications on Recreational Vehicles or Travel Trailers that had a Metal or Fiberglass roof

I didn’t contact them. I have done enough ‘compliance’ stuff- osha, nfpa, building codes- that the language in their literature pretty much said it wasn’t going to be recommended. If it were good for structural applications then the cya wouldn’t exist AND they’d have literature promoting that application.

But thank you for doing that!

 

[12VoltInstalls]

vhb + metal fastener for exterior mounted PV panels seems reasonable to me.

Holding the VHB compressed to the attached surfaces with bolts/screws insures the vhb isn’t the first or last point of failure

 

[PlanetExcellent]

The real stuff is expensive but works. Like have to remove it with a hammer and chisel works!
Buy once, cry once applies here. Use the VHB and rest assured your struts will stay attached.
Recently I bought 80ft of VHB off of Amazon. Turns out it was counterfeit. Painters tape was stronger!

I bought my VHB tape from McMaster-Carr for exactly that reason. Same with stainless steel hardware and u-strut (which they carry in assorted lengths, so I didn't need to cut it.)

 

[TX2AKRV]

You don't just need wind going under the panels to push them up. Wind going over the top of the vehicle can create a lower pressure on top of the panels. This lower pressure can pull the panel

Yup, Bernoulli's principle on lifting of airfoil / airplane wing, though the assumptions made to apply Bernoulli principle on airplane wing lift have been proven wrong in the last few decades by the aerospace industry

We need wind tunnel testing and numerical aero dynamic simulation using super computers to be sure.

Just kidding guys.

Late to this discussion (newbie) but reading with interest as I am about to install a bunch of panels on my Super C in preparation of my trip to Alaska this summer.

 

[TX2AKRV]

Agreed. Some common sense after all.
And why I put some screws in long mounting struts. There's no way I want to lose a panel on the hiway. I'm just not one to horriblize. I'm way too practical for that.

Nothing is ever 100% safe. The Swiss-cheese safety barrier theory.

Once the holes in the Swiss cheese barriers get aligned by whatever cosmic forces, we have a disaster.

I would do both VHB and screws.

I am an engineer (retired))

Thanks for all the posts and opinion here. I learned a lot from all perspectives

 

[Browneye]

Well, at least you're finding all the old threads on the topic.

They really used pebble-finish filon on a super-C??

 

[TX2AKRV]

Well, at least you're finding all the old threads on the topic.

They really used pebble-finish filon on a super-C??

Dynamax Isata 5 on a Ram 5500 diesel 4x4 chasis.

1-piece fiberglass roof over 1/4" plywood and aluminum truss.

Just joined the forum recently. Info is new-to-me and very useful in my planning, designing.

Thank You all