The brackets are best attached to the roof via Sikaflex.

To secure the panels to the brackets I avoid screws because they fall out on corrugations. :(
Even with nuts and bolts I would always use nyloc nuts for security.
For convenience for removal, using some form of captive nut (or bolt) can sometimes be useful. For one installation I used hinges along one side of the panels and small over centre latches on the other side.
I have not had any issue with mixing s/s and aluminium.

Cheers,
Peter

We used rivet-nuts and stainless 4mm bolts. Aluminium rivet-nuts in aluminium and steel in steel or where we need the added thread strength of steel so they can tighten extra tight. Self threading screws are only tight in their threads on a single use, once removed the same screw can not be reused nor can the same hole be used because the thread has been distorted on the original tightening process, that is how they stay done up. Once that distorted screw thread is pulled back through the aluminium the originally cut thread will be stretched and distorted and can not offer the same holding power as it did in the original application.

T1 Terry

-- Edited by T1 Terry on Saturday 26th of May 2018 01:34:19 PM

Would rivnuts be suitable if I choose to use the ABS solar mountings? IE will the ABS be strong enough to hold the rivnut? Ie the ABS solar mount will affix to the aluminium panel frame with 5 rivnuts. I am looking at the 680mm which mount on each end of the panel. Hope I have not confused you.

Peter_n_Margaret wrote:

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T1 Terry wrote:

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We used rivet-nuts and stainless 4mm bolts. 

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Yep, good solution, that is one of the "captive" solutions I referred to, but I would add a locking washer under the bolt head...... and I use M6 nuts (in aluminium or steel) because that is what I have.....

 

Cheers,

Peter

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Seems you can't always edit a post to fix a stuff up.

 Peter is correct regarding the 6mm stainless bolts and using flat washers and spring washers or a pair of the ratchet type lock washers. I thought my second edit had fixed the mistakes but I did neglect to read through it makes sure it read 6mm and not 4mm.

We place a 75 to 100 cm long x 2 cm thick aluminum stripping on the inside of the frame, drill through frame and stripping before we bolt each bracket to the frame. This prevents the bolt ripping through the thin aluminum frame with high wind stress.

Our 315 W panel was ripped off by high cross winds while transitting the Isthmus of Tehuantapec (the narrow waist of Mexico). These winds are world famous and the Isthmus seems to contain most of the wind farms in Mexico. The year before 5 semis had been rolled on one day by these winds near the aptly named town of Las Ventos. Winds have been clocked at 200 kmh. The highest point is about 200 m with mountain ranges that are 3 km or high on either side. So a high pressure in either Pacific or Caribbean with a low pressure on the other creates the winds.

Tied and taped the panel to rear of Roadtrek (we have a 6 m Roadtrek and an 11 m 5th wheel - Roadtrek can handle colonial Mexican towns). We got comments at Mexican gas stations along the lines of "how is that solar panel working back there?" since much of Mexico uses solar. My canned answer was "should work great going north but not that well headed south!" as we were headed to Yucatan.

Reed and Elaine