The amount of surface area that is glued to the roof is so MUCH more than was on the step holder. Also, the solar panels are just sitting there with force downward. That step bracket was experiencing sideways force. I'm sure you'll do what you think best - but I wouldn't undo the solar panels - just add a front faring to make sure the wind goes over the solar panels
I mentioned a year or two ago that everyone needs a Kevin. See if he agrees with me that a bracket (using a adhesive you will trust) and a cable will be a safety that will let you sleep better. Also, the lap sealant has some added hold down power. Then ask Foreman Mateo for the last word.
Adding the sealant to the solar brackets is also good in that it will keep water from getting into the small crevices and possibly freezing causing the adhesive to break loose. It will also reduce mold issues with water entrapment in the crevices. The step bracket must be bolted, it does not have the square inches (~45 sq inches) for a surface adhesive to hold in a sheering load direction. Your solar panels have 3" x 48" x 4, (~576 sq inches) per panel of bonded surface area. The Unimog is looking good.
There's a LOT more bonding area (like you said) on the panels than on the ladder. I'd be surprised if you were even able to remove the solar mounts without delaminating the FRP from the core material. For composite aircraft construction, there are some extremely strong adhesives from Henckle (Hysol) that are designed to bond aluminum to composites. This is a really fun build with all the different challenges of your wall construction!
Just a tip for when you are cutting or sanding aluminum is to use a bar of soap on the disk or sand paper it will cut or sand ten times easier just gives it a bit of lubrication, rub a bit on the disk or sand paper before you start. Daniel NZ
For everyone's reference, I used VHB tape (3" wide) to attach 3 inch wide alluminum rails to fiberglass. Three years now and I have no worries. Trust in VHB tape, just make sure you use enough.
33:37 you are good with solar panels, you would need to roll it over to get them to fly off. I've had mine 8 panels mounted on fiberglass roof with 3m exterior mounting tape and polyurethane coulk around the feet. It's been on for 11 years now.
I built a travel trailer using sandwich construction, I.E. two 1/8" luans glued on one inch styrofoam, sometimes I had to anchor something and of course, scrwing in 1/8" of luan was not an option. So I drilled from the inside a one inch hole then introduced a one inch diamerter aluminum shaft with threaded holes on both ends. The roof was drilled for the size of the machine screw to be used and inside I glued a plate of a larger diameter with a hole to allow to screw from the inside into the aluminum shaft, in addition everything was bonded. Doing so allows to tighten from both sides without compressing the sandwiched wall or roof. I hope, you understand my suggestion, I am sorry, english is not my first language.. BTW, I would use the metal angles under the fiberglass shell as a base to hold the stairway bracket. Cheers from Canada.
Glad Drew wasn’t hurt in the fall! I’m thinking as added security on mine using wide eternabond tape. This actually doesn’t have to be “removed and resealed” like silicone. You may never have to replace it. On a side note I just watched a comparison of eternabond vs gorilla and gorilla won by about 12-15 pound pull weight. Totally surprised. You guys will figure it out. Probably already have. 😅
Go forward, keep what you’ve got, add from there. Not having an internal frame is a game changer for mechanical structural security. I am shocked that my shuttle bus, with an internal 1” steel tubing cage front to back, has better structural integrity than a monster off road MOG thing. Surprised. Went thru Cat5 hurricane in bus, it took my solar panels & unistrut mounting hardware. But the good news is upon replacement, and going up one size in bolts etc, I’m now have a hardware wind rating faster than I’ll ever drive. 🤣. What you said at the end… if they fly off it could be a huge liability. What about rivenuts ? What about through bolting ? Not pretty, but macho trucks need nuts and bolts. 🤷🏼♀️😁 it goes with the style of post-apocalyptic survival vehicle. 😁👍🏻 Go ahead and Mad Max it 👍🏻😁👍🏻
Love the video, love your attitude ‘That’ll do, never does” Just remember…. “It’s not the cataclysmic failure, it’s the monumental recovery” Keep up the positive and excellent work 😊
I want you to know I watched you both walk up those steps from behind my fingers lol Like I watch horror movies haha I’m glad Drew didn’t get hurt when the stairs did fall!
I'm glad you have the removable panels. The only thing I can think of is the L aluminum rail to clamp down the panels with two bolts on each end to the roof. Another way is to add a D ring on the panel rail to feed through a tie-down strap without drilling a hole in the roof.
Hope you guys come up with a viable solution.On a side note have you done the axle mod to prevent the portal hub from emptying to the diff.It's a problem with mogs that can be fixed to prevent issues from higher speed driving.Never had the problem with mine but I had a 404 ambulance so old school.Good luck
Thanks! 🙂 Our Unimog does have this! We had Atkinson install their hub vents before they shipped it over. We did it preventatively as we weren't sure if our mog would have this issue but wasn't too expensive.
We looked at adhesives for our panels and I couldn't bring myself to trust them enough. I ended up mounting them with bolts through the roof. Maybe you could drill a 1" access hole in your wood ceiling so you could drill and bolt them down, then design a plug or cover to hide the hole?
Living in the deep humid south I’d also add to consider damp humid climates & its effects on adhesives. We generally don’t do well with any adhesives due to the extreme heat & humidity giving it fits on remaining a dry tight bond…I’ve had some 3M auto type adhesives like reactivate when it gets hot here.
I would also say that surface area on the panels is so big that you should not have problem. Did you notice that bifacial panels are quite a bit heavier than single. That and the fact that reflect light coming under is so small, i went with one sided.
Maybe a wired cable railing through the rail with a small hole to feed the wire and two end brackets to tighten the cable. I'm just brainstorming. Maybe I better shut up. 😂
Good to see you catching a possible future problem. It takes a lot to admit that! It's VERY hard to know about every single aspect, strengths and limitations of each component in a built like yours. Massive complexity! The same goes for working with adhesives. The adhesive you used (Koemmerling140) is a fantastic product. But there are still many things to know: surface prep, working temperature and required glue thickness for maximum bonding strength. If any of these factors are outside the specs, the chances for failures increase! Any PU based adhesive needs at least a 1/8" (2-3mm) thickness for maximum bonding strength and to allow for flexing (expansion/contraction through temperature). With Aluminum you 100% need either an edging primer or activator (all pending on the adhesive). Without that, most PU adhesives will not proper adhere to the metal. Also important is the working temperature. All PU adhesives need at least 24 hours to cure at a minimum of +18C surrounding temperature. Below that number the glue will simply not cure, no matter how long you wait! Humidity is also important as all 1K PU adhesives are moisture curing. Hot humid summer days= fast curing/ Cold dry winter days= no curing. Hope this helps! Keep on rocking!
Thanks for sharing your expertise here! We appreciate all the help you provided and hopefully this information will help someone else not make the same mistake in the future. You guys rock!
I agree with @brandyn6644 that adding a defector to the front of the roof would help minimize the lift force. Safety taglines are a good idea as well. Cheers.
Do not rip it down. Shear force is way less than pull force. Its good. But some is good more is plenty. Can add bolts with fender washers. Really I believe you its good enough. In the end its up to you.
If the panel did come off going down the freeway and hit someone, it could cause a death or deaths. I would suggest going on the side of caution and grit your teeth and put some kind of mechanical solution as backup, i.e. brackets thru the roof screwed at the front and back into a 12 foot long beam going down the outside left and right side of your panel frames and bracketed in. That would require only 4 holes through the roof into the two 12 foot beams (front and back of the right beam, front and back of the left beam). Even if there are no internal beams to screw into in the roof, bolts with large washers would be enough to hold it in place.
The other thing that you should take into consideration is thermal expansion and contraction of the metal roof and aluminum bars (which expand/contract at different rates) with different seasons i.e. winter-summer. Sure it might be holding up now, but after a few summer/winters of the bonds being stressed will they hold over the test of time?
This is something we discussed as well! Deflecting the wind that could get under the panel will eliminate a lot of the lift on the panels. It might be a good thing to do.
I like the wind dam and install it with some L brackets on either side of the solar frame with one of the other adhesives to the roof and then bolted to the existing frame. That way no holes in the roof and a secondary adhesive should give you peace of mind
I am going to make the assumption that the strip holding the stairs was 1 inch wide and 32 inches long and that you weigh 200 lbs and were standing at the top of the stairs. The shear force is 200 lbs spread over 32 square inches, or 6.25 lbs/inch^2. That converts to 936 psf. I assumed 16 psf for the uplift force on my panels. Your panels seem to be about 26 sf. That gives us 415 lbs uplift per panel. The area of adhesive seems to be about 4 x 3.61 ft x 3 in. This equates to 3.61 sf of bonding surface. 415 lbs of force applied to 3.61 sf of area is 115 psf. Or eight times less force than was placed on the stair mount. I am an unlicensed civil engineer who has just spitballed some numbers here, but if I were you, I would just send it and dont drive 100 mph (not that you could) I welcome anyone here to check my numbers.
The panels are flat, they will not be getting anywhere near 200 lbs of shear resistance at any speed equal to a large man lifting something. If you glued a pool noodle or similar under the front panel, you would be removing all wind force other than maybe a bit of airfoil vacuum over the top. It would take an aircraft wing engineer to calculate that. Great that you made them removable, and one of my favorite saying that my dad ingrained in me, "If you have time to do it over, you have time to do it right the first time" doesn't fit in this instance. Maybe asking more questions ahead of time might have helped... I grew up in a time where no adhesives could be trusted over time, so it is hard for me to trust them now. I have some flexible panels that I want to attach to the top of my camper, but need to trust adhesives.
The solar panels won't have as much force, AND they have much much more surface area securing to the roof vs what that tiny bar had on it with a couple hundred lbs pushing side ways on it.
The amount of surface area that is glued to the roof is so MUCH more than was on the step holder. Also, the solar panels are just sitting there with force downward. That step bracket was experiencing sideways force. I'm sure you'll do what you think best - but I wouldn't undo the solar panels - just add a front faring to make sure the wind goes over the solar panels
All great points!
I mentioned a year or two ago that everyone needs a Kevin. See if he agrees with me that a bracket (using a adhesive you will trust) and a cable will be a safety that will let you sleep better. Also, the lap sealant has some added hold down power. Then ask Foreman Mateo for the last word.
Adding the sealant to the solar brackets is also good in that it will keep water from getting into the small crevices and possibly freezing causing the adhesive to break loose. It will also reduce mold issues with water entrapment in the crevices. The step bracket must be bolted, it does not have the square inches (~45 sq inches) for a surface adhesive to hold in a sheering load direction. Your solar panels have 3" x 48" x 4, (~576 sq inches) per panel of bonded surface area.
The Unimog is looking good.
There's a LOT more bonding area (like you said) on the panels than on the ladder. I'd be surprised if you were even able to remove the solar mounts without delaminating the FRP from the core material. For composite aircraft construction, there are some extremely strong adhesives from Henckle (Hysol) that are designed to bond aluminum to composites. This is a really fun build with all the different challenges of your wall construction!
Ahh good to know! The aluminum is the issue here as that's what released the bond. We will be okay with a few little redundant safety additions!
Just a tip for when you are cutting or sanding aluminum is to use a bar of soap on the disk or sand paper it will cut or sand ten times easier just gives it a bit of lubrication, rub a bit on the disk or sand paper before you start.
Daniel NZ
Very smart to make the panels removable! You two are really good at planning for contingencies!
🥰 So thankful we did that so we could remove them to put the lap sealant on!
For everyone's reference, I used VHB tape (3" wide) to attach 3 inch wide alluminum rails to fiberglass. Three years now and I have no worries. Trust in VHB tape, just make sure you use enough.
33:37 you are good with solar panels, you would need to roll it over to get them to fly off. I've had mine 8 panels mounted on fiberglass roof with 3m exterior mounting tape and polyurethane coulk around the feet. It's been on for 11 years now.
Great info, your end product and fit and finish are awesome, thank you
Thanks for watching 😊
Looks pretty solid, I would use Sika 554 going forward :)
U guys got this . Good Luck. Mucho Love from your friend in Michigan Tam. Very happy neither of u got hurt . Take care .
I built a travel trailer using sandwich construction, I.E. two 1/8" luans glued on one inch styrofoam, sometimes I had to anchor something and of course, scrwing in 1/8" of luan was not an option. So I drilled from the inside a one inch hole then introduced a one inch diamerter aluminum shaft with threaded holes on both ends. The roof was drilled for the size of the machine screw to be used and inside I glued a plate of a larger diameter with a hole to allow to screw from the inside into the aluminum shaft, in addition everything was bonded. Doing so allows to tighten from both sides without compressing the sandwiched wall or roof. I hope, you understand my suggestion, I am sorry, english is not my first language..
BTW, I would use the metal angles under the fiberglass shell as a base to hold the stairway bracket.
Cheers from Canada.
Glad Drew wasn’t hurt in the fall! I’m thinking as added security on mine using wide eternabond tape. This actually doesn’t have to be “removed and resealed” like silicone. You may never have to replace it. On a side note I just watched a comparison of eternabond vs gorilla and gorilla won by about 12-15 pound pull weight. Totally surprised. You guys will figure it out. Probably already have. 😅
Go forward, keep what you’ve got, add from there.
Not having an internal frame is a game changer for mechanical structural security.
I am shocked that my shuttle bus, with an internal 1” steel tubing cage front to back, has better structural integrity than a monster off road MOG thing. Surprised.
Went thru Cat5 hurricane in bus, it took my solar panels & unistrut mounting hardware. But the good news is upon replacement, and going up one size in bolts etc, I’m now have a hardware wind rating faster than I’ll ever drive. 🤣.
What you said at the end… if they fly off it could be a huge liability.
What about rivenuts ? What about through bolting ? Not pretty, but macho trucks need nuts and bolts. 🤷🏼♀️😁 it goes with the style of post-apocalyptic survival vehicle. 😁👍🏻 Go ahead and Mad Max it 👍🏻😁👍🏻
Thanks, learned alot. My project requires two 550w panels to be installed on the roof of my 16ft reefer box habitat
Love the video, love your attitude ‘That’ll do, never does” Just remember…. “It’s not the cataclysmic failure, it’s the monumental recovery” Keep up the positive and excellent work 😊
I want you to know I watched you both walk up those steps from behind my fingers lol Like I watch horror movies haha I’m glad Drew didn’t get hurt when the stairs did fall!
I'm glad you have the removable panels. The only thing I can think of is the L aluminum rail to clamp down the panels with two bolts on each end to the roof.
Another way is to add a D ring on the panel rail to feed through a tie-down strap without drilling a hole in the roof.
Don't know what we would've done if we didnt make them removable!!
@@OurWayToRoam You guys are smart to do this. Otherwise, the party is over.
Hope you guys come up with a viable solution.On a side note have you done the axle mod to prevent the portal hub from emptying to the diff.It's a problem with mogs that can be fixed to prevent issues from higher speed driving.Never had the problem with mine but I had a 404 ambulance so old school.Good luck
Thanks! 🙂 Our Unimog does have this! We had Atkinson install their hub vents before they shipped it over. We did it preventatively as we weren't sure if our mog would have this issue but wasn't too expensive.
I made brackets on my 340watt solar panel and used bolts. I dont gonna trust adhesive on panels that can catch wind. Nice to have 1500 watt 🤩
Your mog looks great! 🤩 Drew is a bit obsessed with solar haha. 1500w will be amazing!
We looked at adhesives for our panels and I couldn't bring myself to trust them enough. I ended up mounting them with bolts through the roof. Maybe you could drill a 1" access hole in your wood ceiling so you could drill and bolt them down, then design a plug or cover to hide the hole?
These adhesives have been a wild ride, thats for sure 😂 It's pretty trippy!
Living in the deep humid south I’d also add to consider damp humid climates & its effects on adhesives. We generally don’t do well with any adhesives due to the extreme heat & humidity giving it fits on remaining a dry tight bond…I’ve had some 3M auto type adhesives like reactivate when it gets hot here.
Y’all have the most literal Kevin Power Up in this video ever.
Haha that’s hilarious 😂 a literally Kevin power up!
I would also say that surface area on the panels is so big that you should not have problem. Did you notice that bifacial panels are quite a bit heavier than single. That and the fact that reflect light coming under is so small, i went with one sided.
Maybe a wired cable railing through the rail with a small hole to feed the wire and two end brackets to tighten the cable. I'm just brainstorming. Maybe I better shut up. 😂
Brainstorming is our favorite! Never stop brainstorming 😁
Good to see you catching a possible future problem. It takes a lot to admit that! It's VERY hard to know about every single aspect, strengths and limitations of each component in a built like yours. Massive complexity! The same goes for working with adhesives. The adhesive you used (Koemmerling140) is a fantastic product. But there are still many things to know: surface prep, working temperature and required glue thickness for maximum bonding strength. If any of these factors are outside the specs, the chances for failures increase! Any PU based adhesive needs at least a 1/8" (2-3mm) thickness for maximum bonding strength and to allow for flexing (expansion/contraction through temperature). With Aluminum you 100% need either an edging primer or activator (all pending on the adhesive). Without that, most PU adhesives will not proper adhere to the metal. Also important is the working temperature. All PU adhesives need at least 24 hours to cure at a minimum of +18C surrounding temperature. Below that number the glue will simply not cure, no matter how long you wait! Humidity is also important as all 1K PU adhesives are moisture curing. Hot humid summer days= fast curing/ Cold dry winter days= no curing. Hope this helps!
Keep on rocking!
Thanks for sharing your expertise here! We appreciate all the help you provided and hopefully this information will help someone else not make the same mistake in the future. You guys rock!
I agree with @brandyn6644 that adding a defector to the front of the roof would help minimize the lift force. Safety taglines are a good idea as well. Cheers.
Try a deflector in front of your panels. Should drastically reduce the lifting force
Definitely nothing more reassuring than using hardware. Otherwise a wind fairing strip in the front of the rig would solve any lift issues.
We used a glue that body shops use. Don't remember the name of it has been 4 yrs with no issues.
So happy you found something that worked for you!!
I've only used Sika Flex so I really wanna see how this works out .. but on my 76' Six Pac camper .. so far no issues and it's been about 3 years
Do not rip it down. Shear force is way less than pull force. Its good. But some is good more is plenty. Can add bolts with fender washers. Really I believe you its good enough. In the end its up to you.
You need to prime the aluminum for any adhesive to hold it.
If the panel did come off going down the freeway and hit someone, it could cause a death or deaths.
I would suggest going on the side of caution and grit your teeth and put some kind of mechanical solution as backup, i.e. brackets thru the roof screwed at the front and back into a 12 foot long beam going down the outside left and right side of your panel frames and bracketed in. That would require only 4 holes through the roof into the two 12 foot beams (front and back of the right beam, front and back of the left beam). Even if there are no internal beams to screw into in the roof, bolts with large washers would be enough to hold it in place.
The other thing that you should take into consideration is thermal expansion and contraction of the metal roof and aluminum bars (which expand/contract at different rates) with different seasons i.e. winter-summer. Sure it might be holding up now, but after a few summer/winters of the bonds being stressed will they hold over the test of time?
One alternative is to fibreglass the brackets to the box rather than just gluing it
There was a solar panel that came off a vehicle in Tasmania years ago. From memory, I think it resulted in a fatal car accident.
A slanted wind screen in front of thr panels with additional suports
Definitely thinking this is one of the first things to do
I cut down some white pvc guttering and riveted it to my panels to act as wind diverter at the front of the array.@@OurWayToRoam
Could you possibly add an angle bracket to the front edge of each panel to deflect the airflow from going under it as you drive.
This is something we discussed as well! Deflecting the wind that could get under the panel will eliminate a lot of the lift on the panels. It might be a good thing to do.
I like the wind dam and install it with some L brackets on either side of the solar frame with one of the other adhesives to the roof and then bolted to the existing frame. That way no holes in the roof and a secondary adhesive should give you peace of mind
We’re thinking this is the way to go!
I notice you have metal frame underneath the box. You could attach the frame for your steps without using glue and use nuts and bolts.
We plan on making a little porch that will pull out from inside that framing! Then the steps can mount to the porch 😁
Excellent Idea!
anchor anchor anchor…vibration, wind, rain, heat, cold, torquing,…
I am going to make the assumption that the strip holding the stairs was 1 inch wide and 32 inches long and that you weigh 200 lbs and were standing at the top of the stairs. The shear force is 200 lbs spread over 32 square inches, or 6.25 lbs/inch^2. That converts to 936 psf. I assumed 16 psf for the uplift force on my panels. Your panels seem to be about 26 sf. That gives us 415 lbs uplift per panel. The area of adhesive seems to be about 4 x 3.61 ft x 3 in. This equates to 3.61 sf of bonding surface. 415 lbs of force applied to 3.61 sf of area is 115 psf. Or eight times less force than was placed on the stair mount. I am an unlicensed civil engineer who has just spitballed some numbers here, but if I were you, I would just send it and dont drive 100 mph (not that you could) I welcome anyone here to check my numbers.
Boeing uses Sika for airplane wings
The panels are flat, they will not be getting anywhere near 200 lbs of shear resistance at any speed equal to a large man lifting something. If you glued a pool noodle or similar under the front panel, you would be removing all wind force other than maybe a bit of airfoil vacuum over the top. It would take an aircraft wing engineer to calculate that. Great that you made them removable, and one of my favorite saying that my dad ingrained in me, "If you have time to do it over, you have time to do it right the first time" doesn't fit in this instance. Maybe asking more questions ahead of time might have helped... I grew up in a time where no adhesives could be trusted over time, so it is hard for me to trust them now. I have some flexible panels that I want to attach to the top of my camper, but need to trust adhesives.
The solar panels won't have as much force, AND they have much much more surface area securing to the roof vs what that tiny bar had on it with a couple hundred lbs pushing side ways on it.
Boeing uses Sika on airplane wing construction
Yeah have steps go sideways and you can put handrails on side of truck.
how about nuts and bolts??
Did you rough up the aluminium first, you sand the box to rough it up, you have to do the same to the aluminium
Interesting these panels are no longer sold via the link?
It seems that website buys up extras from big projects and resells them until they’re gone. Not 100% sure but we think that’s what’s happening.
@@OurWayToRoaminteresting i wonder how the warranty works. Maybe better spend the extra $200 and get the Renogy 550w.
We’re not fans of Renogy
@@OurWayToRoamfair enough