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Old 06-30-2017, 12:43 AM   #4
woundedpig
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Default Re: Unexpected response from 3M about VHB 4950 tape for rigid solar panels

Yes, I'm working my way through the 3M data sheets - wish I was a materials chemist. There was a person whose flex panel came off who used Sikaflex 221 as his adhesive. He said that this version of Sikaflex is more sealant than adhesive. His flex panels had a polyethylene coating on the rear that was intended to be protective, but was a very poor bonding surface. He ended up using Eternabond tape around the edges.

It seems hard to argue with the success of AM Solar's use of VHB/no screws, and all the installers who are out there full-time RV'ing and installing systems.

David



Quote:
Originally Posted by autostaretx View Post
Reading the data sheets, the 4950 certainly looks the better way to go.
The only thing 5962 has going for it is a thicker, more conformable layer between the two adhesive surfaces.

The 4950 has a 140 pounds per sq inch straight pull rating, whereas the 5962 is only 90 pounds.
The peel ratings are about the same (25 vs 22 lbs per inch). The overlap shears are the same (80 psi).

4950 family data sheet: http://multimedia.3m.com/mws/media/1...alty-tapes.pdf
5962 (5952 family) data sheet: https://multimedia.3m.com/mws/media/...-vhb-tapes.pdf

... i'd still put bolts and nuts through the leading edge's feet.

Your panels are 5 and a half square feet of (potential) sail... if they start to lift at all at 60 mph, you've got LOTS of force involved. (math may appear here in a bit...)

--dick
(there's another thread of someone having his flexible panels peel off, i don't recall the adhesive or tape he used)
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