Sheida Madanipour
Martha Townsend
WRIT 340
5/2/2014
Illumin Article: Edit
VHB Tape: The Next Duct Tape?
Abstract
In 1980, Minnesota Mining and Manufacturing Company (3M™) patented their
structural VHB (Very High Bond) double-sided tape. The tape is meant to replace most
permanent fasteners such as rivets, spot welds and liquid adhesives. These tapes have been
used in high profile projects such as the Walt Disney Concert Hall as a means of attaching the
external metal panels to the frame of the structure.
Introduction
When hearing the word tape, we automatically think of the typical, translucent,
office tape used to put posters on the wall. It is hard to imagine that it could be structural or
the main connective component for anything larger than an 8.5” by 11” piece of paper.
Within the last 30 years, VHB (Very High Bond) tape has started replacing rivets,
bolts, welds and liquid adhesives in a wide range of applications within the realms of
architecture, appliances, signage, automobiles, and electronics [5, 7]. The versatility of this
product has enabled it to be used in projects as large as skyscrapers and applications as
small as exit signs.
Properties
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VHB is made from acrylic foam which gives the tape its viscoelastic quality; meaning
that the tape exhibits both elastic and viscous characteristics. This allows the foam to
absorb the stress and strain from the materials or products that it is attached to [5, 7].
The elastic component of VHB allows for the tape to be stretched out multiple times
its original length without snapping. The foam core of the tape varies in thickness, ranging
from 0.4 millimeters to 3 millimeters. The thickness, in combination with the materiality of
VHB gives it the viscous quality. Due to the flexibility of the acrylic foam, it is able to mold
to the objects it is adhering to. Even the smoothest surfaces, like aluminum, have micro
ridges that the acrylic adhesive, coating the foam, is able to seep into[5, 9]. This is what
creates the strong bond.
The tape is categorized by two components of the tape: adhesive and foam.
Depending upon the usage of the tape, the combination of the two will vary. For example,
the Low Surface Energy adhesive would be coupled with the Clear foam when connecting
glass to a plastic surface. Whereas, when in a cold environment, connecting a metal vent to
a concrete wall, the Low Temperature Appliable adhesive will be coupled with the
Conformable foam.
Application
VHB tape has a very simple application process, no matter the scale of the project.
The surface area (generally ranging from 12.7 inches to 0.75 inches but can go up to 48
inches) [5] that is in contact with the tape must be wiped down with an alcohol solution
[10]. The tape is applied just like regular double sided tape but once the surfaces are
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adhered with the tape, they have to be set with a roller (fig.1)[10]. Once the rolling is done,
everything is prepped and ready to go.
(fig. 1 http://www.uline.com/images/Class/3M-VHB-tape.jpg)
Like all adhesives, there is a curing period, which is a period of time needed for the
adhesive or material to set: within 20 minutes it will be 50 percent cured and after only 3
days it is 100 percent cured [11].
Why Use Structural Tape?
VHB has many advantages. When comparing the application process of VHB to any
alternative e.g., rivets and bolts, it takes less time and does not require labor intensive work
such as drilling and refinishing [10]. This enables people to install a variety of objects, such
as faucets, bumpers, and even signs within their homes, businesses and cars without
having to hire a professional. Thus, eliminating the cost of labor and reducing the overall
cost of these projects.
Due to the chemical composition and viscoelastic qualities of structural tape, when
it is connecting two objects, there is a degree of flexibility, allowing for the objects to move.
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An example would be when the tape is used as a connector between metal panels on
the façade of a building, like at the Walt Disney Concert Hall (fig.5)[9], and another surface,
usually the steel structure underneath. The metal panel is going to expand and contract
depending on if the external conditions are hot or cold. The alternatives are either bolting
or screwing the metal panels onto the structure which can cause damage to the material as
a result of the metal expanding when hot and shrinking when cold. This not only can cause
damage to the metal panels, it also puts stress on the bolts to keep the sheet onto the
surface.
It is likely that the metal sheet will be more flexible than the bolt and deform at the
points where the bolts are. If the structural tape is used, the foam will be flexible enough to
withstand the amount of expansion and contraction up to three times its thickness and
remain adhered without deforming the metal [7].
Studies performed by 3M™ have shown that also due to these viscoelastic qualities,
that the bond created by VHB tape between two objects is able to withstand 60 mph car
crashes and heavy storms [5]. When exposed to water, dirt, and even motor oil, VHB tape
remained 100 percent adhered to the attached surface.
Problems
Although VHB performs well when exposed to dynamic stresses, such as vibrations
caused by earthquakes, when exposed to static stresses, the tape has a tendency to creep
[6]. This means that when a large load is acting upon the tape, over time, it can move.
Therefore, VHB is not ideal to use to connect critical structural components within a
building such as beams to girders (fig.2). 3M™ suggests on their website that in order to
prevent creep from static loads when applying the tape, there must be four square inches of
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VHB to every pound of weight that it is supporting [9]. Although, the company provides a
recommendation to prevent the tape from moving, the product has not been used or tested
enough with girders and beams to comfort architects and engineers for this particular
application.
(fig. 2 connection between girder or beam and joists)
Another problematic application of VHB is in the vicinity of certain chemicals. 3M™
conducted several studies, placing VHB in direct contact with different fuels and solvents.
When exposed to salt water, the tape remained 100 percent adhered to the surface, but,
when exposed to gasoline its adhesion retention jumped down to 37 percent [5]. At places
such as gas stations, or laboratories if the tape comes into contact with gasoline or another
solution that it is incompatible with, they would react poorly and the VHB would stop
working properly. Depending upon the application of the tape, in the event that is stops
working, the outcome could range from catastrophic to annoying.
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Projects Connected By a Thread
(fig. 3 Burj Al-Arab, http://www.theluxtraveller.com/wp-content/uploads/2013/04/Dubai.jpg)
VHB has been used in several high profile buildings around the world. In Dubai, the
glass curtain wall system of the hotel, the Burj Al-Arab is adhered with VHB tape (fig.3)[5].
The glass curtain wall façade is comprised of glass panels connected to one another with
metal cladding. In a typical glass curtain wall system there is structural silicone buffer, seal
and connection between each panel. [1, 2] In the Burj Al-Arab, this structural silicone has
been replaced with structural tape. The curing time for silicone is longer, and requires
post-application cleaning to avoid sloppy design. [1] With the structural tape, there is no
need to clean the glass and requires less time for application. The decision to use VHB tape
in this hotel was a direct result of the tape’s ability to withstand the dynamic load from the
strong wind conditions prevalent in Dubai, which is the same reason why it is used within
glass systems and not structural elements such as beams or girders. [2, 5] The loads that
beams and girders hold are static, which is not an area of strength for VHB tape.
(fig.4 metal cladding connected to structure)
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Another façade system using VHB tape is the Walt Disney Concert Hall by Frank
Gehry in Los Angeles, California. [5] The façade is comprised of folded metal panels linked
together by a connector lip and VHB tape (fig.4).
(fig.4 Walt Disney Concert Hall)
The lip links the metal pieces and the tape adheres and seals them. This way each
individual panel is connected to the others and also to the metal structural skeleton
underneath them, creating a texturized surface undisturbed by bolts and welds (fig.5) [3].
(fig.5 Walt Disney Concert Hall)
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(fig.6 Yetti Fish House, http://www.voyagerindustries.com/files/cache/bb4ddb742f2e91ca7fc829c6e8e1505f.jpg)
A smaller scale application of structural tape is with Yetti aluminum fish houses (fig.6).
These fish houses are trailers that connect to the back of any car, used for ice fishing. The
trailer can house equipment and allows the fishermen to stay in a warm shelter while
fishing. These small aluminum houses are constructed of a basic frame with panels that
attach to it. The panels are completely adhered to the aluminum frame with VHB tape. This
allows for the fish house to make less noise while on the road by buffering the two metal
surfaces and preventing them from hitting against each other. The absence of screws and
bolts and coupled with using an aluminum base structure the house is much lighter,
allowing it to sit atop the ice.
Potential
The future of this product seems endless. The simplicity of application allows for
anyone to construct and repair buildings and electronics. If people were able to install their
own faucets and even their own roofs, the savings in cost would be a huge benefit for the
masses to use VHB tape. Perhaps it’ll be the next duct tape?
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About the Author
Sheida madanipour is a 4th year architecture student at the University of Southern
California.
Name: Sheida Madanipour
Phone: 408-666-2003
Email: madanipo@usc.edu
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