RV News RVBusiness 2021 Top 10 RVs of the Year, plus 56 additional debuts and must-see units → ×

Thread Tools Search this Thread Display Modes
Old 06-29-2017, 12:50 PM   #1
1 Rivet Member
Currently Looking...
Austin , Texas
Join Date: Aug 2009
Posts: 7
Odd response from 3M about VHB 4950 tape

I contacted 3M trying to get some help figuring out how to get appropriate width of VHB to get full coverage of some solar panel mounts I plan to use for some Renogy panels.

I got this response: ? Is this a CYA response? Maybe I should have expected it. I don't know what tape number or how much they use to hold trucks together but it is not 4 sq inches per pound of weight supported.



__________________________________________________ ____________

Thank you for contacting 3M, where we apply science to life.

I am not sure where you heard the 4950 VHB tape is frequently used for this type of application. We do not suggest that particular VHB, and in fact, VHB can be used for this application, but we suggest it in conjunction with mechanical fasteners. VHB was not intended for this application as a sole means of bonding it due to many factors. The 4950 tape is mostly used for metal to metal applications. We have other VHB tapes that will bond much better to fiberglass. I would suggest to test our VHB tape #5962 along with our adhesion promoter 111. We suggest to use 4 square inches of tape, per pound of weight it will support. I have attached the data page for review. Please read over all the application instructions as surface prep, how much tape to use, set up time, etc. is all listed. You won't need to get an exact width of tape for the width of the panels, as long as you can get the 4 sq. inches per pound around the diameter. Also, use the mechanical fasteners in addition to the tape. This is suggested to support the wind loads it will see going down the highway.

You can find these products on Amazon.com, R S Hughes, or Grainger, usually in smaller rolls or broken cases.

If you need further/additional assistance or prefer to speak directly with a specialist please call 1-800-362-3550 for the first available representative.


Lisa P.
3M Product Application Support
Industrial Business
woundedpig is offline   Reply With Quote
Old 06-29-2017, 12:55 PM   #2
Half a Rivet Short
2017 30' Classic
Carlisle , Pennsylvania
Join Date: May 2017
Posts: 9,102

If you have a 50 lb solar panel and go with 200 square inches, that's four strips of 50 square inches each. If they are 48" long they each would be an inch wide. At 36" long you would get up to about 1.5" wide. Overkill maybe. I've had a number of things like this degrade in odd ways at either very high or very low temperatures.

uncle_bob is offline   Reply With Quote
Old 06-29-2017, 01:34 PM   #3
4 Rivet Member
Durango , Colorado
Join Date: Jan 2014
Posts: 333
Originally Posted by woundedpig View Post
The 4950 tape is mostly used for metal to metal applications. We have other VHB tapes that will bond much better to fiberglass.
From the information in the response, it appears they didn't realize you were bonding the panels to an Airstream. They assumed you were bonding to a fiberglass roof whereas Airstreams have a metal roof. That makes all the difference in the bonding strength.

Lewster uses this tape all the time for solar panel attachment to Airstreams and so far hasn't had any problems.
RVDreamer is offline   Reply With Quote
Old 06-29-2017, 02:39 PM   #4
Rivet Master
Al and Missy's Avatar

2002 30' Classic S/O
Melbourne Beach , Florida
Join Date: Nov 2013
Posts: 4,170
I thought Lewster used UHB tape, a different animal.

“You cannot reason someone out of a position they have not been reasoned into"
Al, K5TAN and Missy, N4RGO WBCCI 1322
2002 Classic 30 Slideout -S/OS #004
2013 Dodge 2500 Laramie 4x4 Megacab Cummins
Al and Missy is offline   Reply With Quote
Old 06-29-2017, 03:12 PM   #5
Rivet Master
lsbrodsky's Avatar

2012 25' FB International
Trent Woods , North Carolina
Join Date: May 2013
Posts: 3,087
My solar from AMSolar came with VHB tape attached to the feet and that is what Lewster uses, I believe. He also uses Sikaflex to seal and increase adhesion around the feet.

lsbrodsky is offline   Reply With Quote
Old 06-29-2017, 03:47 PM   #6
1 Rivet Member
Currently Looking...
Austin , Texas
Join Date: Aug 2009
Posts: 7
Well, actually - I was considering using VHB 4950 with a new fiberglass roof on a Class C motorhome application because I thought that was the practice at AMSolar. Should have specified that. Big difference.

woundedpig is offline   Reply With Quote
Old 06-29-2017, 05:08 PM   #7
Not a forum whore...
PDXPaulie's Avatar
Friday Harbor , Washington
Join Date: Jun 2017
Posts: 18
I just added a panel to the top of my AI. From their website MSDS, 3m VHB 4950 will hold something like 80 lbs per square inch when fully cured. If you're using the Renogy mounts, 4x 1"x4"strips = well you can do the math.

Heres the link. It does say metal, glass, and "high energy" substrates, theres also another sheet that says 4950 is an acceptable application for glass/epoxy substrates. But you can also check with Lewster or call or email Roger at AM Solar.

PDXPaulie is offline   Reply With Quote
Old 06-30-2017, 12:54 PM   #8
3 Rivet Member
Pygmypoacher's Avatar
1979 31' Sovereign
Black Diamond , Washington
Join Date: Oct 2015
Posts: 192
I'm installing 3 160w AMSolar panels on my AS. I stuck with the VHB tape provided by AMSolar but doubled up the feet - two per corner. No screws through my roof!

Sorry about the pun... Couldn't resist.
Pygmypoacher is offline   Reply With Quote
Old 06-30-2017, 01:13 PM   #9
Rivet Master
WayneG's Avatar
1984 27' Airstream 270
Scotia , New York
Join Date: Oct 2012
Posts: 1,082
The tapes strength is reduced at higher temperatures.
My panel mounts use tape & screws
WayneG is offline   Reply With Quote
Old 06-30-2017, 03:03 PM   #10
:SPACE A" S/O 11 Air19745
guskmg's Avatar

2006 34' Classic S/O
Fort Worth , Texas
Join Date: Feb 2007
Posts: 1,397
I have 8 Panels secured buy lewsters 3M tape and Silkaflex around the foot perimeters. After install, trailer was towed from FL to TX at 80 mph. None have come loose
in one and a half years.
guskmg is offline   Reply With Quote
Old 06-30-2017, 10:14 PM   #11
3 Rivet Member
adobehome's Avatar
1962 19' Globetrotter
New River , Arizona
Join Date: Jun 2006
Posts: 114
I did the same as others stated above. 3m VHB tape bought from Amazon and Silkaflex around the feet of the mounting system that I made. I installed one panel on roof of my 1962 Globetrotter nearly 2 years ago. I cleaned the metal of the roof with mineral spirits, first. I live near Phoenix, AZ, travel all over the southwest and, last summer, traveled over 10,000 miles to Acadia National Park and back. NO, the GT is NOT garage kept and YES, we get a bit warm around here. No problems.
Judy & Bill
'62 GT
adobehome is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
VHB installation in winter Troutboy Boondocking 2 01-07-2017 08:22 PM
F/Contained Emergency response lightng General Motorhome Topics 6 06-24-2010 08:14 AM
Confused Over Response to Posting flyfshr Forum Admin, News and Member Account Info 3 09-12-2005 11:38 PM
Fire Response System Over59 General Interior Topics 4 07-31-2004 11:23 PM

Featured Campgrounds

Reviews provided by


This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.

All times are GMT -6. The time now is 02:26 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.