SparkyGuy wrote in
obal.net:

Duct tape is crap. It is actually not good for ducts (heating and
cooling causes the adhesive to quickly fail):
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POPULAR SCIENCE (December 1998)

Tape That Doesn't Live Up to its Name

DUCT TAPE is one of the most versatile materials ever invented.
You can
patch a tent, seal up a box, or even repair a leaky garden house with
it. But according to the Department of Energy's Lawrence Berkeley
National Laboratory, there's one thing duct tape doesn't do well: seal
a duct.

In leak tests at the lab, researchers Max Sherman and Iain Walker
forced
alternating hot and cold air flows through finger-jointed metal ducts
sealed with a variety of products --including duct tape, clear plastic
tape, foil-backed tape, mastic, and injected aerosols. The
researchers also baked the sample ducts at temperatures of 140 to 187
degrees F, simulating the conditions in many attics.

"Of all the things we tested," says Sherman, "only duct tape
failed. It
failed reliably and quite often catastrophically."

Duct tape consists of a cloth backing and a rubber adhesive. "We
think that
heat degrades the glue, and that's what's killing the duct tape,"
Walker says.

The researchers are recommending that duct tape manufacturers
reformulate
the glue to work better at higher temperatures, and that longevity
standards be developed for all duct sealants. Whether that will
happen remains to be seen; as of press time, manufacturers were
studying the test results.

In the average house, 20 to 30 per cent of the energy used for
heating and
cooling is lost through ducts.
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There is a different type of duct tape that works. It's black and
actually sold in better heating & cooling supply stores.

The original that I remember was available from drama supply stores
called gaffer's tape. It is of a different constitution and doesn't
leave a residue when you take it off after a week or 2.



Duct tape just a tradational ha-ha. Personally I like to stick pun
intended) with Covalence Adhesives products like Polyken & Nashua.

http://covalenceadhesives.com