Gluing plastic solar panel mounts to trailer roof.

[digimark]

Hello. I purchased a 2'x3' 85W solar panel to mount to my cargo trailer roof. I'm using these black ABS plastic solar panel mounts from Bright Solar, which
calls for 3M Sikaflex 252 glue. I'm going to clean the trailer surface then layout the panel mounts (four corners, two short bars and two long bars) and
glue them to the roof.

Manufacturer page: http://www.brightsolar-power.com/index. ... ew/99.html

They look like this: http://www.youtube.com/watch?v=KgXYD21ysiU

Question: Does anyone know how I apply this glue? Thick or thin? Since there is no hole being cut/drilled, do I need to apply a caulk bead line around
each mount? Any advice? Thanks in advance.

[eamarquardt]

252 is made by Sika and 5200 is made by 3M. Both are moisture curing polyurethanes.

They are great adhesives. They take days or more to cure. I've never worked with Sikaflex but 5200 is gooey as all get out and difficult to clean up any mess you make. If I were in charge I'd mask off the top of your roof to the exact pattern of your mount. Then I'd mask off the sides of your mount above the surface to be glued. I'd spread out the adhesive around the surface of your mount to about 1/8-3/32 thick (or more than enough to account for any gaps that might result as a result of curvature of your roof). Then I'd firmly press the mount to the roof squeezing out the excess. Then, while holding the mount in place, I'd wipe off the excess leaving a nice cove around the base of your mount. Then I'd apply a couple of pieces of tape to hold the mount from slipping out of place. After the urethane went off, I'd remove the tape.

You might glue a couple of pieces of scrap plastic together to get a sense for how this stuff is to work with. I've also found that if you seal the end of an open tube with the cap and perhaps some plastic wrap and place it in the freezer it will keep almost indefinately. If you just replace the cap and leave it at room temperature it will, eventually go off (it might take months or longer at room temperature to go off, but frozen, I've had it last for years).

Hope this helps.

Cheers,

Gus

[Shadow Catcher]

I have the same mounts including the longitudinal that I imported from the Chinese manufacturer. I used 3M VHB tape to hold them on after consulting with a 3M engineer, there are calculations needed for wind shear and a certain amount of surface area. The thought of having our solar panel come lose at speed scared me no end. They have withstood in excess of 120 mph, speed plus wind. One thing that is not apparent is that the surface area for gluing on the mounts is not all that great, because they are hollow, the flanges are the area you have to use and having only the four corners is not enough you will need the http://www.brightsolar-power.com/index. ... w/139.html .

[digimark]

Thanks Gus and Shadow -- that's exactly the info I was looking for. I have pairs of both the long and short side pieces and two of the
cable entries also. I've ordered the Sikaflex glue but I don't mind putting that aside and going with VHB tape if that's a better
solution... (should I switch to the tape? And any advice about applying it?) I really want this to hold, same nervous vision of panel
lifting off at speed haunts me.

Shadow -- how big is the panel on your CT? (size and watts.)

[Shadow Catcher]

The VHB tape is easy to apply but do the pre-cleaning carefully, I used the 3M cleaner. The mounts I received were not flat on the bottom and had to be sanded. One advantage is that the tape can be removed with an orange cleaner. http://solutions.3m.com/3MContentRetrie ... =ImageFile
The panel is a 185W high voltage panel and is 32" x 62" and works very well.

[bdosborn]

The VHB tape is easy to apply

There's a bunch of different VHB tapes, which one did you use? I used 4941 on my flexible panels but I don't remember why I picked it now...


Bruce

[digimark]

I'm leaning towards the VHB tape because it looks like a cleaner install, but not sure, since the Sikaflex glue is already on its way.

Gus -- would normal blue painters tape work for masking, or should I use something stronger? (Guessing stronger...)

Shadow Catcher -- you're just about the only person I've met who has used the same solar panel mounts. A few more questions please?

1. What screws did you use to secure the panel to the mounts? Did you drill pilot holes and then screws, or use bolts? Any recollection
what size/length screws or bolts you used?

2. To use the VHB tape, is it double-sided? Cut to size, apply to mount and then press on to the roof, holding it? Or the other way
around -- cut and apply to roof then press the mount onto it and hold?

3. How did you bring the panel wiring inside?

My panel has two 3' wires with M4 connectors coming off of it. I bought a 30' cable with the opposite connectors on it, and plan to
chop it in half and add crimp-on ring terminals to attach to my battery. (My charge controller is a Morningstar Sunkeeper 6 that
attaches directly to the panel's underside.) I plan to mount the panel to the front of the CT's roof, then drill two holes into the top front
wall of the trailer and bring the cables inside to where the battery is located. I bought two of the black plastic ABS cable entries
from the same panel mount people and will glue them on over the holes with the cables running through them.

I really appreciate the responses -- I need a lot of hand-holding on this.

[eamarquardt]

Hi,

Regular masking/painters tape will do fine. The stuff is really gooey though. When I had to replace a leaking window in our boat, the frame was like a pretzel by the time I got it off. Fortunately the window was under warranty and the builder provided me with a new one as they knew I'd never get it off intact. They had used 5200. I also used 5200 to reseal the keel (all 6600# of it) to the boat. All I had in the bilge after that was DUST!

Cheers,

Gus

[eamarquardt]

Hi,

Regular masking/painters tape will do fine. The stuff is really gooey though. When I had to replace a leaking window in our boat, the frame was like a pretzel by the time I got it off. Fortunately the window was under warranty and the builder provided me with a new one as they knew I'd never get it off intact. They had used 5200. I also used 5200 to reseal the keel (all 6600# of it) to the boat. All I had in the bilge after that was DUST!

Cheers,

Gus

[Shadow Catcher]

Shadow Catcher -- you're just about the only person I've met who has used the same solar panel mounts. A few more questions please?

1. What screws did you use to secure the panel to the mounts? Did you drill pilot holes and then screws, or use bolts? Any recollection
what size/length screws or bolts you used?
I used a security bolt and drilled and taped the hole. I drilled the mount on the panel and then taped the panel and then reamed the mount hole. There are a bunch of them and so strength is not paramount. I did use stainless steel.

2. To use the VHB tape, is it double-sided? Yes Cut to size, apply to mount, make sure ALL of the mount has tape on it so there is no room for water to get in, This is visco elastic so it will seal small gaps. and then press on to the roof, holding it? Yes, clean well and realize once it is down it aint coming back off with out a lot of effort.

3. How did you bring the panel wiring inside? I used a Perko marine fitting that uses 10 ga wire. Since this is a high voltage panel, typically more than 40V in full sun, voltage drop was not a concern.

I found the mounts on a European supplier and asked if they were willing to send to the US and since they were not went hunting for the manufacturer, in China. I found a much earlier version of the website with fewer options i.e. white. I think they were having QC problems as the long pieces were not flat on the bottom and required a good bit of sanding.

Gus I do not remember which tape but the 4941 sounds about right ? and I found a big roll on ebay, it is gray in color.

[OverTheTopCargoTrailer]

Here is a US company in calif that sells your abs panel mounts.
They have white & black.


http://www.unlimited-solar.com/Universal_Solar_Panel_4_Corner_Drill_free_Mount_p/u-mo-j03.htm


One caution on installing cabel - wire through the roof, even with special connectors
I noticed water was able to migrate down the wire, lucky I had a second drip loop,
Water dripping on electric components is not good.


On my panels I just used metal brackets with VHB tape ....
They were sitting in water much of the time a still worked great,
Installed on unfinished galvanized roof , lightly sanded, cleaned with rubbing alcohol ,
Panels were 210 watts 39 x 59"
I used sheetmetal screws into the panel side frames


Jerry

[tnriverluver]

On running the solar panel wires. On My install I ran them through the roof vent and then fed them to their final destination. By doing this you can make the wires go up before they go down and prevent any possibility of leaks. Study your vent carefully and you should be able to figure out a way to do this also.

[roadinspector]

On running the solar panel wires. On My install I ran them through the roof vent and then fed them to their final destination. By doing this you can make the wires go up before they go down and prevent any possibility of leaks. Study your vent carefully and you should be able to figure out a way to do this also.

This would work exceptionally well if you have a Maxxair vent cover over the roof vent.

Earnest

[digimark]

Wel, it took me a while to get the screws and washers I wanted. This morning I walked out to the trailer and got this done:

1. Cleaned the trailer roof surface and the ABS mount surface with 99% IPA and let it dry/evaporate.
2. Pre-drilled a 5/64" pilot hole in each screw location on the mounts.
3. Laid everything out with the panel sitting on the mounts for position. Marked the locations with a blue magic marker.
4. Applied the VHB tape as we'd discussed, covering the entire underside of each mount. I pressed them hard with my
thumb.
5. Pulled the tape seals and, after positioning them in their locations, pressed down hard on each mount multiple
times. I hope that's good enough for adhesion, plus leaving the solar panel sitting there, because I couldn't think of
a way to add pressure over time without standing on the ladder for too long.

Here's a picture of the result. Note the panel is just resting on the mounts but is not screwed into place. I'm going to
wait a day or two for the tape to set up as best it can. Then I'll be using #10 stainless steel self-drilling, self-sealing
screws. (The washer has a neoprene membrane which will help prevent it from working loose.)

With the slight curve in the trailer roof I was worried that the panel wouldn't rest flat, but I can see there is some
flex. If the VHB tape holds like it's reported to... then I think I'll be alright.

[wtcreaux]

Another option is screwing into the roof spars (yeah, I know, I wasnt too crazy about putting 4 holes in the roof, but it is SOLID)



I used a LOT of silicone calk. BTW, the mounts are 2x4 mounts at Home Depot that I bent one of the wings back 180 degrees making my own "Z-mount" for about 50 cents each.



Below are the cables entering the side.