Which type of screw/bolt for solar panel installation?

Leakylunar

Leakylunar

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Hopefully last question regards solar installation?
what are the best screws/bolts for securing the panel to the side/corner plastic mounts.
I’ve searched and thought there might be better solutions to self tappers ?
 
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Saw these, if I get self tappers what of size? As I don’t want to get to small!?
 
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Hi Leaky
I have always used 10mm stainless nylock nuts and bolts on mine, easy to check for tightness and nip up if necessary.

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Went with 8mm stainless bolts and nylock nuts when I fitted to previous van after advice from an installer I spoke to at the Lincoln show a couple of years ago. He was sceptical about self tappers that used a ‘rubber’ washer as he was convinced they deteriorated over time and lost their elasticity and then the screws worked loose with vibration?
 
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I use alloy brackets but still need screws, I use stainless steel 6mm socket cap screws with nylock nuts.
When using Stainless steel with aluminum do make sure you use a barrier to prevent electrolysis reaction which causes corrosion. I use silicone grease, an old sailors trick is to use Evostick.
I don't recommend using s/s self tappers as the alloy will corrode away around them.

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I used the self drilling screws - 5.5x25mm for the vertical fixing into the roof & 5.5x38mm for the horizontal fixing into the panel frame (the support brackets are thicker horizontally so 25mm aren't long enough). I put a ring of Sikaflex around the underside of each screw hole onto the roof to seal it. Seems to have worked although early days
 
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You might want to check out 'Rivnuts', though if you have a fibregalss roof they may not be suitable.
 
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Theres a solar panel on my roof fitted with aluminium brackets and self tapping screws....I'm convinced it was fitted when the van was new 15 years ago .... it's still there and screws haven't come slack or the panel frame rotted etc

The newer panel is fitted on plastic mounts again with self tappers on it and its tight too ....that was fitted 2 years ago by previous owner.
 
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Lenny HB said:
I use alloy brackets but still need screws, I use stainless steel 6mm socket cap screws with nylock nuts.
When using Stainless steel with aluminum do make sure you use a barrier to prevent electrolysis reaction which causes corrosion. I use silicone grease, an old sailors trick is to use Evostick.
I don't recommend using s/s self tappers as the alloy will corrode away around them.
Click to expand...
Completely forgot to mention the barrier between bolts and panel frame! Very slightly oversize hole, pack around bolt with silicone grease and cover bolt and nut with the same grease once fixed was the recommendation.
 
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Thanks again everyone, the panel is now mounted with 200mm long 50mmx50mm 3mm alloy angle in each corner and seems sturdy.
Tried it yesterday and all seems ok, just need to fabricate a front spoiler and get charge settings for the lead acid battery on the victron.

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Lenny HB said:
I use alloy brackets but still need screws, I use stainless steel 6mm socket cap screws with nylock nuts.
When using Stainless steel with aluminum do make sure you use a barrier to prevent electrolysis reaction which causes corrosion.
I don't recommend using s/s self tappers as the alloy will corrode away around them.
Click to expand...
There’s a product called Duralac made for this. It’s used in marine applications a lot. It’s very expensive though for the amount you will use
 
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Scotsblood said:
Completely forgot to mention the barrier between bolts and panel frame! Very slightly oversize hole, pack around bolt with silicone grease and cover bolt and nut with the same grease once fixed was the recommendation.
Click to expand...
I use a quick spray of white grease. It isn't only stainless that has problems with aluminium - steel fasteners are as bad with the added problem that they rust anyway.
 
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The only need for any mechanical fixings is when fixing the panel to the support brackets or angles. You do not need any screws or bolts to fix the support brackets to the roof, just a properly applied layer of the appropriate Sika product.

On both my motorhomes the ali angle bracket supports for the two solar panels I had were fixed to the roof only with sika. I fixed the panels on my previous motorhome and the dealer fixed them on to my present motorhome and both relied upon ali brackets glued to the roof. Between them I have done a total of about 50,000 miles in the motorhomes in all weathers and never had a panel come off.

I have never heard of such a fixing failing on this forum. There was a failure reported a couple of months ago which caused some initial concerns, but it was subsequently confirmed that the failure occurred between the bracket and the panel because of a lack of fixings, not between the bracket and the roof.
 
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Will be fixing my panel soon using the usual corner and additional plastic mounts.

I was all for SS bolts and nuts but then realised I can not remove the panel from the mounts as the mounts will be glued onto the roof.

So I am thinking of using SS self drilling screws, without a rubber washer under the head.

Has anybody experience of using them?

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We did not use those plastic mounts. Instead used 50 x 50 ali angles. Used pop rivets to fix the panel to the angles. that way if I ever wanted to remove the panels I could drill the rivets out.
 
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peterc10 said:
We did not use those plastic mounts. Instead used 50 x 50 ali angles. Used pop rivets to fix the panel o the angles. that way if I ever wanted to remove the panels I could drill the rivets out.
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Agree. I use adhesive-only to attach to roof and it's difficult to fully clean release agent off plastic.
 
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Nightmare topic. Was going to use plastic mounts, sikaflex'd to the roof then self tappers for the panel to these. However on contacting Sikaflex for advice on type to use, they wanted tech details of the type of ABS plastic - good luck trying to find out that one! Ended up using ali angle (which Sika were happy to advise type of sealant/adhesive to use), plus s/s tech screws similar to the Screwfix ones shown above for extra peace of mind, then fixed panels to these with rights and s/s mate bolts, so easy enough to remove panels if needed. Wondered about aerofoil, but seeing a YouTube video where foils produced a suction effect on the back end of the panel, followed their example and didn't fit one.
 
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Sorry, predictive text! Should read rivnuts and M 8 bolts!

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peel rivets ? but seal the middle of the rivet and overcoat with sika.
Peel rivets peel and spread out when reacted with a rivet gun or rivet pliers.
 
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Stainless steel bolts and nyloc nuts and sikaflex to stick to roof. 12,000 miles no probs.
 
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peterc10 said:
The only need for any mechanical fixings is when fixing the panel to the support brackets or angles. You do not need any screws or bolts to fix the support brackets to the roof, just a properly applied layer of the appropriate Sika product.

On both my motorhomes the ali angle bracket supports for the two solar panels I had were fixed to the roof only with sika. I fixed the panels on my previous motorhome and the dealer fixed them on to my present motorhome and both relied upon ali brackets glued to the roof. Between them I have done a total of about 50,000 miles in the motorhomes in all weathers and never had a panel come off.

I have never heard of such a fixing failing on this forum. There was a failure reported a couple of months ago which caused some initial concerns, but it was subsequently confirmed that the failure occurred between the bracket and the panel because of a lack of fixings, not between the bracket and the roof.
Click to expand...

Hi Peter - do you know what would be the appropriate sika fixing for an ali bracket to a steel roof (or where I could find out)?

Thanks
 
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