Choosing the BEST ADHESIVE

[danman81]

Hello everyone!!!  This is my second post because I got an amazing response to my first one!!  I will try to stay on topic as much as possible!  I would like to attach semi-flexible solar panels on the roof of my van.  There are a number of reasons why I would like to use these, but i will not talk about them here.  As @GotSmart pointed out to me, these panels were not recommended because the winds could blow them off.  I would like to use a piece of sheet metal (or plastic) in the middle to be screwed/bolted to the roof and then use an adhesive to bond the solar panels to the sheet metal.  I'm looking for a permanent solution that will handle cold and cold, basically the strongest possible adhesive.  Maybe epoxy?  I guess you could say I'm looking for a structural adhesive.  I would also secure the eyelets that are on the solar panels.  Getting pretty worried something is gonna go wrong at high speeds, but of course i never speed.   :huh:

love this forum!!!

 

[GotSmart]

The problem is the panels ripple in the wind.  The constant flexing loosens the wire connections and de laminates the layers after a while .  Also, there  MUST be air space under them or heat builds up.  

3M makes the best adhesives.  They have a super industrial velcro also.  

There are threads on here.  Key words.  flex, adhesive.  The SEARCH link is top center right. 

That will save you a lot of time. 

 

[highdesertranger]

3M 5200. however GotSmart has made some very good points against flexible panels, don't disregard his points. I might have missed it on the other thread, but what type of vehicle are these panels going on? highdesertranger

 

[danman81]

Thanks again @GotSmart!  that was a quick response!  the panels have soldering connections directly on the back instead having a junction box on the front like some flexible panels, so I don't intend to have any exposed wiring -- is that what you mean by loosening wire connections, the exposed junction boxes?  I would worry about delamination and thank you for bringing that up because I would have never thought about that!  I really don't know what you could even do for something like that except maybe seal the edges along with the edge of the metal sheet I am proposing?  Really am lost for ideas there!  In terms of air, this plan would let air in between the grooves on the roof or rather within the grooves, although I'm not sure that would be enough air.  I'll look more into the 3M adhesives -- it looks like their structural epoxy could be a good fit.    Didn't even think about velcro!   

Thanks also @highdesertranger!  That is not the first time I've heard about 3M 5200 for sure...  I hear lots of good things about it!  Looks like I have a little more research to do now!  Lol @GotSmart has been very helpful over in the insulation section where i have a similarly named thread : He is like my Obiwan Kenobi now haha.   The van I plan on is a white ford transit cargo van, i need stealth all the way babyyyy

Love this forum!!!

 

[highdesertranger]

does that Ford Transit have ribs like a regular van? also I hope you realize that stealth in the city is highly over blown. anybody who wants to know, already knows you are sleeping in your van. highdesertranger

 

[danman81]

does that Ford Transit have ribs like a regular van?  also I hope you realize that stealth in the city is highly over blown.  anybody who wants to know,  already knows you are sleeping in your van.  highdesertranger

Yes, it has regular ribs like a regular van does~  @GotSmart was talking about heat issues and needing ventilation underneath the solar panel.  I'm not sure if those ribs will provide enough ventilation, but I'm just hoping it will  :huh: :s

As per stealth, there's so much to talk about and probably would be best to start a new thread or join another thread or something like that, but I would like to go as much stealth as possible basically because stealth mean security and security means safety, so I am trying to maximize stealth if i can at all possible.  It's probably my #1 priority actually for my build.  I feel myself going out on a tangent now so I'll stop, but so much to talk about it!  The way I see it is, the less people who know I'm sleeping in my van the better.  For example, I am employed full time in a nice cushy job, and I would not want them to find out...  It takes away from the whole "keeping up with the Jones's" effect that we try so hard to portray.  It's funny because I'm criticized for "being a homeless person" when I probably make more money than the people saying I'm homeless in all fairness.  sorry need to start another thread lolol

 

[GotSmart]

Yes, it has regular ribs like a regular van does~  @GotSmart was talking about heat issues and needing ventilation underneath the solar panel.  I'm not sure if those ribs will provide enough ventilation, but I'm just hoping it will  :huh: :s

I see you do not understand.  If the panel is mounted against a corrugated style roof, it is still mounted on metal.  The ribs are under the metal, (inside the van) and you are wanting to super insulate the van.  The surface will become extremely hot.

http://www.meguiarsonline.com/forum...-in-the-sun-How-HOT-does-your-car-s-paint-get  

As per stealth, there's so much to talk about and probably would be best to start a new thread or join another thread or something like that, but I would like to go as much stealth as possible basically because stealth mean security and security means safety, so I am trying to maximize stealth if i can at all possible.  It's probably my #1 priority actually for my build.  I feel myself going out on a tangent now so I'll stop, but so much to talk about it!  The way I see it is, the less people who know I'm sleeping in my van the better.  For example, I am employed full time in a nice cushy job, and I would not want them to find out...  It takes away from the whole "keeping up with the Jones's" effect that we try so hard to portray.  It's funny because I'm criticized for "being a homeless person" when I probably make more money than the people saying I'm homeless in all fairness.  sorry need to start another thread lolol

Thread started

 

[danman81]

Thanks again @GotSmart!  I surely will not move forward with any plans until I have your blessing!   Please understand tho, being an engineer, telling me that something can't be done is like... a grand puzzle or game.. just so much fun to try and solve, even if there is no solution  

Are you referring to the tops of the ribs, which would come into direct contact with the solar panel?  This is very good point and I do not yet have a solution, but I'm still trying to think of one.   If you look at the roof, the tops of the ribs, which is really all the space between the ribs has a lot more surface area than the rib indentations themselves, so you are correct and this would make it even a bigger problem in terms of heat.  I plan on having a separate metal or plastic sheet between the solar panel and the corrugated roof so I can achieve the greatest surface area for my adhesive, and will be using "flush" screws to screw down the metal or plastic sheet.  One idea would be to use some type of weather-proof insulation sandwiched between roof and the metal or plastic sheet, and only on the surfaces in between the ribs to allow for that little bit of ventilation where the ribs are.  The insulation would have to be thin and weather proof...  maybe a sheet of silicone, similar to some pot handlers?   Maybe it would also make sense based on your comments to use a plastic sheet instead of a metal sheet.  I was thinking of the metal sheet because I would be able to screw it down to the roof more securely, but maybe I can find just the right screws for the job (hopefully!).  Then, I can use an insulating type of hard plastic like polystyrene or polycarbonate.  Pretty much out of ideas on this at this point so i will do some more thinking, but I have now proposed 2 thin layers of insulation separating the solar panel the roof with a small amount of ventilation but not a lot I realize.  Thanks @GotSmart!!!

 

[GotSmart]

I am telling you why it is not the preferred way of doing it, not that it cant be done.  There has been thousands of hours of testing and study on this subject.  Unless there is a minimum of an inch air space between the panel, and the surface below it there will be heating problems.  The wind and rippling cause a different problem of stress, and the over heated and stress combine for delamination and failure.

Just remember, in case of maintenance, the panels will need to be removed at some point.  

I installed a ladder rack, and ran channel between them.  The panels are all but invisible. 

It is snowing where I am so I could not get the exact shots I wanted, but these will work.

 

[BradKW]

With a high top van, you can get away with panels pretty easy with a little camo on edges. 

I've seen variation of this that should work for a low roof, where they had white metal made up in shape of a sigma...gave panels a inside lip to sit on 1 inch over roof, ran full length of van so had an OEM look to it. 

If you weren't starting so far in the red trying to meet your solar needs, I'd say sure, play around with flexi's. But from everything I've read, and given what your objectives are, I'd steer clear of them...

 

[highdesertranger]

if you mount those panels right on the roof the low spot of the ribs is going to fill with debris. like leafs, pine needles, snow and dirt. highdesertranger

 

[SternWake]

My friend is making a show van a extended body early 80's Dodge, and has three of the Unisolar E-pvl68 that are 9 foor something long.

His plan is to fill up the corrugations with a non corrosive closed cell foam then fiberglassing over it, then have a thin sheet of stainless, to which the panels have already been adhered, attached to the roof.  Not sure when he will get to that. 

I have a PVL-68 that uses mc3 connectors.  I painted my fiberglass roof, filled the little 'step' in the back with bondo, and ran the panel up and over the crown.  There is a little ridge in the panel just past the apex as while it can bend, it cannot compress or stretch.

I am happy for the extra wattage in addition to my framed Kyocera 130 watt, But i want more.

No doubt Unisolar's output is lessened by heat since it is adhered directly to the roof and was designed to be.


If I were to do it over again I'd get the largest single framed panel like the Kyocera 325 watt,   reenforce the frame a bit and  support the center of the panel , a little better from underneath,  and paint the aluminum frame white then get a MPPT charge controller capable of dealing with the high voltage.

I ran a bead of 3m 5200 around the perimeter of the Unisolar panel to cover the black Butyl edge.  IT did not bond to the butyl.  I also held the mc3 cables to the roof with blobs of 5200 every 8 inches or so. 

I'm thinking of getting a  flexible panel, and making a low profile frame for it to account from the crown on my roof in the space I have remaining, with a nod toward ventilation under it. But a larger Nod toward preventing flapping in the slipstream at 90mph

When the roof is curved, the slighest breeze over the roof will cause the air to accelerate under the  flat panels.  My framed Kyocera has a large junction box on the underside and I mounted it so that this was practically resting on the roof, and front two corners, there is barely 1/2 inch clearance.

I can tilt the panel upward.  90 degrees toward either side of the van, but when the directed at the sun at 10 noon and 2, there is no significant difference in Panel  temp flat or tilted.

 

[danman81]

I am telling you why it is not the preferred way of doing it, not that it cant be done.  There has been thousands of hours of testing and study on this subject.  Unless there is a minimum of an inch air space between the panel, and the surface below it there will be heating problems.  The wind and rippling cause a different problem of stress, and the over heated and stress combine for delamination and failure.

Just remember, in case of maintenance, the panels will need to be removed at some point.  

I installed a ladder rack, and ran channel between them.  The panels are all but invisible. 

It is snowing where I am so I could not get the exact shots I wanted, but these will work.

Thanks, those are awesome pictures and very cute van!!  The maintenance issue is a good point and I will have to re-engineer my solution to allow for removal of the panels for maintenance or eventual replacement.  For the non-flexible panels, the ladder rack is definitely the way to go!   Stay warm!

 

[danman81]

With a high top van, you can get away with panels pretty easy with a little camo on edges. 

I've seen variation of this that should work for a low roof, where they had white metal made up in shape of a sigma...gave panels a inside lip to sit on 1 inch over roof, ran full length of van so had an OEM look to it. 

If you weren't starting so far in the red trying to meet your solar needs, I'd say sure, play around with flexi's. But from everything I've read, and given what your objectives are, I'd steer clear of them...

Thanks for the pictures @BradKW! I love the way your install looks -- It's extremely stealthy/professional looking.  The white metal rails you fabricated definitely look very OEM.  Are you worried they will have the overheating problem that others have brought up and is there air beneath them?   Are those monocrystalline cells?  What kind of panels are those?   Do you have any issues with debris getting underneath?  How are they attached to the roof?  I'm still on the fence about the flexible panels, but I will find a way if i can!  Love your van!

 

[danman81]

if you mount those panels right on the roof the low spot of the ribs is going to fill with debris.  like leafs, pine needles, snow and dirt.  highdesertranger

Great point @highdesertranger.  You convinced me that I will need to fill in the ribs somehow!

 

[danman81]

My friend is making a show van a extended body early 80's Dodge, and has three of the Unisolar E-pvl68 that are 9 foor something long.

His plan is to fill up the corrugations with a non corrosive closed cell foam then fiberglassing over it, then have a thin sheet of stainless, to which the panels have already been adhered, attached to the roof.  Not sure when he will get to that. 

I have a PVL-68 that uses mc3 connectors.  I painted my fiberglass roof, filled the little 'step' in the back with bondo, and ran the panel up and over the crown.  There is a little ridge in the panel just past the apex as while it can bend, it cannot compress or stretch.

I am happy for the extra wattage in addition to my framed Kyocera 130 watt, But i want more.

No doubt Unisolar's output is lessened by heat since it is adhered directly to the roof and was designed to be.


If I were to do it over again I'd get the largest single framed panel like the Kyocera 325 watt,   reenforce the frame a bit and  support the center of the panel , a little better from underneath,  and paint the aluminum frame white then get a MPPT charge controller capable of dealing with the high voltage.

I ran a bead of 3m 5200 around the perimeter of the Unisolar panel to cover the black Butyl edge.  IT did not bond to the butyl.  I also held the mc3 cables to the roof with blobs of 5200 every 8 inches or so. 

I'm thinking of getting a  flexible panel, and making a low profile frame for it to account from the crown on my roof in the space I have remaining, with a nod toward ventilation under it. But a larger Nod toward preventing flapping in the slipstream at 90mph

When the roof is curved, the slighest breeze over the roof will cause the air to accelerate under the  flat panels.  My framed Kyocera has a large junction box on the underside and I mounted it so that this was practically resting on the roof, and front two corners, there is barely 1/2 inch clearance.

I can tilt the panel upward.  90 degrees toward either side of the van, but when the directed at the sun at 10 noon and 2, there is no significant difference in Panel  temp flat or tilted.

Wow, thanks for the amazing response @SternWake -- so helpful!  Sounds like your friend is doing something very similar to what I'm doing. I would love to get in touch with him to share ideas, and i think we will both be facing the same problems.  For example, is he worried about not being able to remove them?  I am going back to the drawing board to see if i can do something to have them removable.  Also, what made him decide on spray foam insulation?  I will also need some type of spray-on or liquid insulation to fill the gaps in the ribs.  Does he think the foam will be weather resistent enough?  I could see vibration also being a problem in the long-run too if he intends it to be permanant.  Also, has he though about using a thermal resistant sheet of plastic instead of stainless, which is very conductive as you know.

Is there a reason you painted your roof?  Was it to make it white?  It looks like Bonda is pretty cool stuff.  Do you know what the thermal resistance properties of it are?  Would love to see pics of your setup if u have them.  Effiency of panels is always going up, so I would like to find a way make them removable/replacable if I can, but that's gonna have to be something pretty creative with flexible panels. How is the 5200 holding out?  Let me know how you end up designing the new flexible panel if you go down that road -- we are both worrying about the same thing in terms of ventiliation/heat and flapping.  For flapping, I'm thinking a metal or plastic sheet, and bonding the solar panel directly to it with a strong adhesive would be the best solution.

 

[GotSmart]

Great point @highdesertranger.  You convinced me that I will need to fill in the ribs somehow!

The ribs (water channels) should be left alone.  They serve a purpose.

 

[SternWake]

Danman,


My Online  friend's project vehicle is pretty much well overboard, going for the Vanner's display type van.  He's not concerned about stealth, his is about the wow factor, and the functionality of a good stand alone electric system and some rather ridiculous levels of complexity, less so about dwelling, but of course there is some crossover.

We have various disagreements about the mounting of his panels to the roof, and kind of just let the subject drop.  I am not a fan of expando foam in contact with painted metal, while he insists it is inert once cured.

Part of his desire to fill the roof valleys is noise suppression, He has even added roof ribs and done a bunch of acoustic testing for resonance, and it might very well be the quietest Van interior on the road.

The panel heating is something he is not going to make any compromises for.  The panels must be as invisible from a 6' tall  human's eyes, but there is still a little roof crown so this is unlikely.

My panel is painted white to match my white roof, which was painted white for heat purposes, then the van followed suit.

I think he already has the thin stainless sheet for adhering the panel trio to.  I doubt he has any plans on removing them once they are installed.

I'll never try and remove my unisolar stick on panel from the roof. 

Everything is a compromise. if you want the flexible panels directly on the roof, well you will just need more solar to account for the efficiency loss at higher panel temperatures.  As long as the panel does not flap around it 'should' not have the same issues as renogy 100 watters.

 

[BradKW]

Thanks for the pictures @BradKW! I love the way your install looks -- It's extremely stealthy/professional looking.  The white metal rails you fabricated definitely look very OEM.  Are you worried they will have the overheating problem that others have brought up and is there air beneath them?   Are those monocrystalline cells?  What kind of panels are those?   Do you have any issues with debris getting underneath?  How are they attached to the roof?  I'm still on the fence about the flexible panels, but I will find a way if i can!  Love your van!

Sorry for the confusion...and even more sorry that I don't own the van in the pics

That is a conversion that I've been using as my base guide for a while now...the solar setup is described here: http://www.stealthsprinter.com/van-build/solar-electrics/

The owner has posted here before and his contact info is on his site...I've found he is very helpful and responds to emails.

 

[danman81]

Danman,


My Online  friend's project vehicle is pretty much well overboard, going for the Vanner's display type van.  He's not concerned about stealth, his is about the wow factor, and the functionality of a good stand alone electric system and some rather ridiculous levels of complexity, less so about dwelling, but of course there is some crossover.

We have various disagreements about the mounting of his panels to the roof, and kind of just let the subject drop.  I am not a fan of expando foam in contact with painted metal, while he insists it is inert once cured.

Part of his desire to fill the roof valleys is noise suppression, He has even added roof ribs and done a bunch of acoustic testing for resonance, and it might very well be the quietest Van interior on the road.

The panel heating is something he is not going to make any compromises for.  The panels must be as invisible from a 6' tall  human's eyes, but there is still a little roof crown so this is unlikely.

My panel is painted white to match my white roof, which was painted white for heat purposes, then the van followed suit.

I think he already has the thin stainless sheet for adhering the panel trio to.  I doubt he has any plans on removing them once they are installed.

I'll never try and remove my unisolar stick on panel from the roof. 

Everything is a compromise. if you want the flexible panels directly on the roof, well you will just need more solar to account for the efficiency loss at higher panel temperatures.  As long as the panel does not flap around it 'should' not have the same issues as renogy 100 watters.

Thanks @SternWake~  That's really interesting about your friend's van!  I'm also worried about the use of spray foam because it dosen't stand up to mold very well, and I would worry about moisture getting into contact with it.  I think spray foam is just not really designed for vehicle insulation -- and dosn't stand up to vibration very well over time.  I'm been searching for a sealant that could stand up to vibrations by drying soft and rubbery for noise suppression like you, but still insulating.  Noise suppression is very important for me also, and the additional sound barrier on the roof would be beneficial.  What I've found is silcone sealant, so this could be a candidate for filling in the ribs as well.  If anyone knows anything else that is like this, please let us know!

You make a very good point about he efficiency going down, and that alone might just push me over the edge to use regular solar panels attached to a roof rack, but i'm just not ready to give up yet.  how much efficiency do you estimate that you lose with your unisolar panel because of the heat?

a flexible panel solution will probably have to be permanent.