Even if the rubber based adhesive in duct tape would hold mup for 20
years without drying out (It won't), the tape itself is not rigid
enough to hold anything significant as a beam.

Stretch

) said...

The center upright post will be a steel column, however, a duct tape post
is also an option I have considered.

Even if duct tape had the rigidity to be useful as a beam (I doubt it),
using it for a post would be out of the question as it would have to be
non-compressible to hold up as a post.

Tension loads and compression loads are two very different things.

--
Calvin Henry-Cotnam
"Never ascribe to malice what can equally be explained by incompetence."
- Napoleon
-------------------------------------------------------------------------
NOTE: if replying by email, remove "remove." and ".invalid"

Strength of materials has been a focus of study for many for a long
time. Wood is a very interesting composite material itself, with sawn
lumber having very different properties from the various laminates.
(Ever try to split a piece of plywood?) What is important here is the
orientation of the fibers in the layers and how they're bonded.

When done properly, you can build very stiff, strong structures like
the DeHavilland Mosquito or the "Spruce Goose." Or PT-Boats,
minesweepers, Skimmars.

Duct tape really doesn't even work very well for taping ducts.

Have you considered spaghetti? "Pasta post & beam" maybe? Certainly
better in compression or beam.

John

wrote:

Everyone knows that lamination is the key to structural strength.
Lately, they are making beams out of plywood. For example, they make
a 2 inch thick 12 inch wide "plank" that is supposed to be stronger
than a 2X12 board. I see these things being used in a lot of places
these days.

So, if they can hold up a house with strips of shaved wood that are
less than 1/8th inch thick, why not laminate duct tape.
I want to create a beam capable of supporting an entire house, and
made entirely of laminated duct tape.

Are there any scientists out here that would know how to determine the
amount of layers, width, thickness, and final dimensions of the beam?
Also, how many rolls of tape would be needed? The beam needs to be
40 feet long. There will be one center post at exactly dead center
(20 feet). The house will be a two story home, 24 feet wide and 40
feet long. This beam will support the center of the home, with 2X8
floor joists resting on this beam, with structural walls down the
center of both the first and second floor, up to the peak of the roof.
The ends of the beam will sit on a poured concrete foundation. The
center upright post will be a steel column, however, a duct tape post
is also an option I have considered.

Meeks

This obviously is a question for Red Green...

A quick set of calcs gives a beam depth of about 32".
I would reccommend against it though, I think you'd have a very hard
time getting it passed by the building dept or getting an engineer to
stamp your plans

Forget about a DT post unless you wrap a 6" diameter shipping tube with
many layers.

Duct tape has a lot of uses, some reasonable, many not. This set of
contemplated uses is not .

Stick with wood as basis material for you construction; either sawn or
engineered. Floor trusses might be an option.

cheers
Bob

According to BobK207 :
Duct tape has a lot of uses, some reasonable, many not. This set of
contemplated uses is not .

You've obviously never seen Red Green.

Have you ever seen a gadget that would allow you to change
tires on a car while the car is moving? Red
Green has done it with duct tape.

My favourite: an elevator built out of a hot water tank,
telephone booth, some rope, pulleys and duct tape.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

Strength of materials has been a focus of study for many for a long
time. Wood is a very interesting composite material itself, with sawn
lumber having very different properties from the various laminates.
(Ever try to split a piece of plywood?) What is important here is the
orientation of the fibers in the layers and how they're bonded.

When done properly, you can build very stiff, strong structures like
the DeHavilland Mosquito or the "Spruce Goose." Or PT-Boats,
minesweepers, Skimmars.

Duct tape really doesn't even work very well for taping ducts.

Have you considered spaghetti? "Pasta post & beam" maybe? Certainly
better in compression or beam.

Yeah, but you can fake compressive-strength by constraining things
that are strong in tension. That's how inflatables work.
So you make the top half of the "beam" out of long tubes of duct-tape
rammed full of more duct-tape with a mechanical press. Flip the thing
over to get a reverse camber, tape stub-outs made of complete rolls
to the (now upper) surface, and string duct-tape cables along that,
along the stub-outs.

So it's do-able, just stupid.

Chris Lewis wrote:

According to BobK207 :
Duct tape has a lot of uses, some reasonable, many not. This set of
contemplated uses is not .

You've obviously never seen Red Green.

Have you ever seen a gadget that would allow you to change
tires on a car while the car is moving? Red
Green has done it with duct tape.

My favourite: an elevator built out of a hot water tank,
telephone booth, some rope, pulleys and duct tape.

My take has always been there's virtually always far more to the
structure than is shown, but it is a hoot...

wrote:

Everyone knows that lamination is the key to structural strength.
Lately, they are making beams out of plywood. For example, they make
a 2 inch thick 12 inch wide "plank" that is supposed to be stronger
than a 2X12 board. I see these things being used in a lot of places
these days.

So, if they can hold up a house with strips of shaved wood that are
less than 1/8th inch thick, why not laminate duct tape.
I want to create a beam capable of supporting an entire house, and
made entirely of laminated duct tape.

Are there any scientists out here that would know how to determine the
amount of layers, width, thickness, and final dimensions of the beam?
Also, how many rolls of tape would be needed? The beam needs to be
40 feet long. There will be one center post at exactly dead center
(20 feet). The house will be a two story home, 24 feet wide and 40
feet long. This beam will support the center of the home, with 2X8
floor joists resting on this beam, with structural walls down the
center of both the first and second floor, up to the peak of the roof.
The ends of the beam will sit on a poured concrete foundation. The
center upright post will be a steel column, however, a duct tape post
is also an option I have considered.

Meeks


I forwarded your question to our engineer and this is what he
told me:

Due to the inability to predict the actual construction
methods used to construct the beam or the capabilities of
those constructing it, he would have to build in a safety
margin far greater than he would ordinarily do for a standard
construction beam. That said, he advised using a double 2x12
beam as a form to start with and wrapping it with layers of
duct tape to achieve a uniform depth of 19'- 7" and a uniform
thickness of 8'-7". He will assume no liability or warranty
for actual performance.

--
Robert Allison
Rimshot, Inc.
Georgetown, TX

Obviously, if you are using the good stuff, it will take less. That
Home Depot 3-rolls-fer-a-buck junk is gonna take lots more, and you
will see significant delamination over time. My cousin used duct tape
as earthquake strapping for his So Cal home, and was real happy with
the results. It took him about 17 rolls cause it was a two story house
with a basement, and of course, he ran each strap under the foundation
and then up over the roof and all.

Good luck,
Neil

I heard this several years ago, but it seems appropriate with the recent
Star Wars release:

Duct tape is like the Jedi Force. It has a light side, a dark side, and it
it can bind the universe together.

As a side note, my brother in law, who was involved with auto racing (his
dad worked for Champion) always referred to the stuff as "Racer's Tape"
since the drivers used it for quick repairs in the pit during the races.

Mike O.

One. If it's large enough.