Aluminium Angle for mounting Solar Panels??

Discussion in 'Solar Power' started by Revolvor, May 4, 2016.

  1. Revolvor

    Revolvor Funster

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    Help!!! .... I am confused!

    I am just about to fit a 100W Solar panel to my MH. I have bought 4 x lengths of 300mm long 2.1/2" x 2.1/2" x 1/8" Aluminium Angle, together with Sikaflex 512 and Sika 205 Activator.

    However in a post about cleaning under solar panels, I received this reply:

    "Don't use bare aluminium directly on the roof. Use anodised or stainless steel then you can attach them without screws. Adhesive eventually lets go of bare aluminium because the oxide layer to which it is stuck absorbs water & corrodes the aluminium. You can also get plastic corner mounts that can be stuck to the roof."

    I have read numerous posts on this forum regarding using Aluminium Angle, and have never seen this warning before. Also there is no mention of it on the various Sika Data Sheets I have read - including their pre-treatment one - even though it does not mention Sikaflex 512 directly. https://usa.sika.com/dms/getdocument.get/4c07225f-6914-3451-9f4b-ad1cf9cbfbed/Primer%20Chart%20PU%20Sikaflex%20200.SikaTack%20Series.pdf

    Should I be looking at an alternative bracket material?
     
  2. Techno

    Techno Funster Life Member

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    Where did you get that reply? :ROFLMAO:
     
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  3. Boringfrog

    Boringfrog Funster

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    Beat me to it.
     
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  4. Revolvor

    Revolvor Funster

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  5. Terry

    Terry Funster

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    There is going to be a lot of panels flying off roofs :)
     
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  6. Leftlegger

    Leftlegger Funster

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    to oxidise aluminium needs oxygen,if it's sealed with sikaflex then surely it cant IMO.(y)
     
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  7. Techno

    Techno Funster Life Member

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    I've never witnessed any evidence of that and Sikaflex is designed for direct use on bare aluminium. Carry on.
     
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  8. John Laidler

    John Laidler Funster

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    Some quick googling suggests the aluminium oxide does reduce the bond strength by up to 50% but given the area you are considering this won't matter a jot. I can't see a long term problem either, bonding aluminium is a common practice and it wouldn't be done if the joints fell apart afterwards.

    I would just roughen the aluminium with fine sand paper first. I also used screws on mine in addition to the Sikaflex. :)
     
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  9. Terry

    Terry Funster

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    I'll reserve judgement for around 15 yrs -that is the oldest I have taken off and examined --I found and warned of some Sikaflex not sticking to some plastics -letting go after 3-4 yrs ;)
     
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  10. Revolvor

    Revolvor Funster

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    Thanks guys for all the reassurance.... I will proceed as planned.
     
  11. Techno

    Techno Funster Life Member

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    More often because the plastic wasn't prepared correctly before applying adhesive
     
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  12. Techno

    Techno Funster Life Member

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    These will come unstuck for sure if the boding surface hasn't been scoured with wire wool and cleaned with sika 205 or equivalent image.jpeg
     
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  13. Revolvor

    Revolvor Funster

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    @Techno - Andy, where do you get these cable entry boxes? Most of the ones I have seen are much larger.

    Also, what is the typical time interval between applying the Sika 205 and the Sika 512?
     
    Last edited: May 4, 2016
  14. Gromett

    Gromett Funster

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    I used Sikaflex and some self tappers. I put spacers between the base of the aluminium angle and the roof to ensure a 2mm gap was kept when I screwed down.
    5 years and counting. This is on a PVC though.
     
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  15. Techno

    Techno Funster Life Member

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  16. Boringfrog

    Boringfrog Funster

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  17. Techno

    Techno Funster Life Member

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    As soon it's dry
     
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  18. Revolvor

    Revolvor Funster

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  19. Terry

    Terry Funster

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    Probably Andy but I know the plastic was prepared right I did it(y) and two yrs later it let go -noticed it could move so I pulled it off and used other stuff that it stayed stuck with :)
     
  20. tonyidle

    tonyidle Funster

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    My experience with aluminium corrosion is admittedly on small parts - I suspect a decent area would be fine. Having said that I wouldn't use it. Mine are on 1mm stainless 'L' section bent up for me by a local metalworks. Little difference in price (to me - the owner is a good friend).
     
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