VHB Tape to mount Thule Tracks

rean1mator · 04-29-2018, 12:57 PM

Has anyone used any of the general purpose VHB tape to mount thule tracks on to their penthouse roof?

The thule tracks have a plastic bottom and in doing some research online it appears that vhb tape might exhibit low adhesion on some plastics due to the plasticizers reacting with the bonding agent in the vhb tape.

Of course this dawned on me to check that there might be an issue with plastic after I applied the tape to the bottom of all four thule tracks that I bought. But atleast I didn't mount them on my roof yet.

Really wanted to install my solar panels on tracks so that I could remove the panels if necessary.

rean1mator · 04-29-2018, 01:04 PM

Ok so just did some more googling and found this on the 3m site specifically for the model number vhb tape I'm using: (5952). So it looks like this version is ok with plastic.

Convenience Meets Extreme Bonding Power
Our 3M™ VHB™ Tape consists of a durable acrylic adhesive with viscoelastic properties. This provides an extraordinarily strong double sided foam tape that adheres to a broad range of substrates, including aluminum, stainless steel, galvanized steel, composites, plastics, acrylic, polycarbonate, ABS and painted or sealed wood and concrete. Our bonding tapes provide excellent shear strength, conformability, surface adhesion and temperature resistance. They are commonly used in applications across a variety of markets including transportation, appliance, electronics, construction, sign and display and general industrial. Reliably bonds a variety of materials with strength and speed for permanent applications.

Recommended Applications

Decorative material and trim
Nameplates and logos
Electronic displays
Panel to frame
Stiffener to panel
3M™ VHB™ Tape 5952
3M™ VHB™ Tape permanently adheres one substrate to another and spreads the stress load across the entire length of the joint Dream, Design, Deliver with the 5952 Family of 3M™ VHB™ Tapes
The 5952 family of 3M™ VHB™ Tapes utilizes modified acrylic adhesive on both sides of a very conformable, adhesive foam core. The combination of strength, conformability and adhesion makes this family one of the most capable and well-rounded 3M™ VHB™ Tapes. It is specifically designed for good adhesion to high, medium and lower surface energy plastics and paints, metals and glass. Applications for this tape include bonding and sealing polycarbonate lens over LCD, signage and windows to post-painted control panels.

boywonder · 04-29-2018, 02:30 PM

I thought about it quite seriously for my Yakima tracks, but ended up with a couple of screws/bolts.

I think it would work fine. I've used it on many work-related projects; the stuff is permanent and amazing.

rean1mator · 04-29-2018, 07:56 PM

Yeah so got it mounted it up. Still have another set to do for my second panel but gonna let this one "soak" for a bit before adding the second one. Just kind of trying to get over the mental block of using vhb tape vs screws took awhile to commit to getting it mounted. haha.

Quote:

Originally Posted by boywonder

I thought about it quite seriously for my Yakima tracks, but ended up with a couple of screws/bolts.

I think it would work fine. I've used it on many work-related projects; the stuff is permanent and amazing.

DrewMoto · 04-30-2018, 01:49 PM

Subscribed for the results. Seems pretty iffy.

The stuff is touted as permanent and a suitable replacement for screws only for architectural facades. Then, 3M recommends loading the tape to about 0.26 psi for permanent static loads in shear.

I don't know the dimension of your roof rack mounts, but I'll guess you have eight of them and they measure 3 inches by 6 inches at the base. So you'll have 8x3x6=144 square inches of VHB. Safely loaded to 0.26 psi, you can support 37.4 pounds permanently in shear. This force will be in the form of drag.

If the frontal area of your rack is 4 feet x 1 foot, the force due to drag is...
39 pounds at 60 mph
69 pounds at 80 mph

The friction alone from the weight of the rack setting on the roof will help support some of that, but I wouldn't count on it. You could have something on your rack trying to lift it away from the roof (surfboard, canoe, mattress).

Sources
3M data: http://multimedia.3m.com/mws/media/7...oduct-info.pdf
Force due to drag calcs: https://sciencing.com/convert-wind-s...e-5814125.html

rean1mator · 04-30-2018, 02:01 PM

I'm actually using the tape on the bottom of my 60" Thule tracks and mount,g my panel on the track. Surface area shouldn't be a problem. Was more conncerned that the bottom of the track was plastic.

Quote:

Originally Posted by DrewMoto

Subscribed for the results. Seems pretty iffy.

The stuff is touted as permanent and a suitable replacement for screws only for architectural facades. Then, 3M recommends loading the tape to about 0.26 psi for permanent static loads in shear.

I don't know the dimension of your roof rack mounts, but I'll guess you have eight of them and they measure 3 inches by 6 inches at the base. So you'll have 8x3x6=144 square inches of VHB. Safely loaded to 0.26 psi, you can support 37.4 pounds permanently in shear. This force will be in the form of drag.

If the frontal area of your rack is 4 feet x 1 foot, the force due to drag is...
39 pounds at 60 mph
69 pounds at 80 mph

The friction alone from the weight of the rack setting on the roof will help support some of that, but I wouldn't count on it. You could have something on your rack trying to lift it away from the roof (surfboard, canoe, mattress).

Sources
3M data: http://multimedia.3m.com/mws/media/7...oduct-info.pdf
Force due to drag calcs: https://sciencing.com/convert-wind-s...e-5814125.html

1der · 04-30-2018, 02:08 PM

There is going to be lift if air can get under the panel.

Is this a standard solid panel or flexible type that will be adhered to the roof? If it is a solid panel, it is best to have at least an inch of air space below the rails of the panel, otherwise efficiency is reduced.

rean1mator · 04-30-2018, 02:36 PM

40x40 hard panels are being used. AM solar sells their mounting feet with vhb tape and have stated they have never had any issues with tape coming off.
(https://amsolar.com/rv-mounting-accessories/91m-35mz)
With 60"X 1.5" of vhb tape on each thule track, vs the 1.5" by 1" or so surface area of the am solar mounts, as long as there are no issue with the tape adhering properly to plastic(which was my only concern), I think I should be fine. I'll guess we'll see!

Quote:

Originally Posted by 1der

There is going to be lift if air can get under the panel.

Is this a standard solid panel or flexible type that will be adhered to the roof? If it is a solid panel, it is best to have at least an inch of air space below the rails of the panel, otherwise efficiency is reduced.

Jeffrey · 04-30-2018, 03:06 PM

If you think I'd trust my $7.5K bike to a piece of tape on the roof, you've been smoking too much cheap wine.

Bbasso · 04-30-2018, 03:34 PM

Stainless steel hardware VS Elmer's Glue...
Sure one is more work, but far less risk.