Fixing Aluminium Brackets to Vehicle Body
Fixing Aluminium Brackets to Vehicle Body
(OP)
I would be grateful for some advice on how best to fix aluminium brackets (35mm x 100mm) to Promaster van. The brackets are used to support a large (25 kg) solar panel on the roof of the van. I am concerned about vibration, long term rubbing wear and electrolytic action of the dissimilar metals. I am thinking of using 2mm neoprene gasket between the van roof and the brackets, with stainless steel nylocked bolts. Is this the best method of fixing or can you suggest alternative methods ? Perhaps a Polyurethane adhesive ??
Thanks in advance
Thanks in advance
RE: Fixing Aluminium Brackets to Vehicle Body
What makes you think that the brackets are nearly strong enough for the job?
You need to look into how the manufacturer attaches roof racks to this vehicle.
My guess is that they screw bolts through the roof into a threaded doubler plate.
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P.E. Metallurgy
RE: Fixing Aluminium Brackets to Vehicle Body
There are 6 brackets each with 2 mounting holes. The M6 bolts will either be screw into rivnuts or into a spreader plate inside the van. The panel is 1.7m x 1m, so the weight/bracket(s) is evenly distributed. Also, as the panel is parallel (air gap approx 40mm) I don't think there is much wind loading as the moving air can pass freely over both upper and lower surfaces.
RE: Fixing Aluminium Brackets to Vehicle Body
Unless you've run CFD, that's just a wild a$$ guess; if the panel isn't absolutely parallel to the airflow, you've got a monster spoiler or wing, depending on its angle of attack. There's a reason why OEM solar panels are embedded in the roof. Moreover, because the airflow is a function of vehicle speed, the structure will have periodic loading, which makes the fastening system all the more critical.
TTFN (ta ta for now)
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RE: Fixing Aluminium Brackets to Vehicle Body
Any reason to not mount this 5-10mm from the roof and then add a fiberglass faring to blend it to the roof?
You might also need to tie the reinforcement plates in the roof together with some steel bracing.
I actually doubt that the standard frame for the solar panel will work in this application.
On the roof of my house the wind might be 60mph, on the roof of a van it could easily be >120mph (van + wind speeds) which would be roughly 4 times the mechanical loading.
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P.E. Metallurgy
RE: Fixing Aluminium Brackets to Vehicle Body
RE: Fixing Aluminium Brackets to Vehicle Body
I personally prefer to use sealants over gaskets and use sealing washers under the bolt heads.
RE: Fixing Aluminium Brackets to Vehicle Body
"Everyone is entitled to their own opinions, but they are not entitled to their own facts."