Aquaponics Digest - Sun 01/30/00
Message 1: Re: UV - Poly - Al Tape
from Adriana Gutierrez & Dennis LaGatta
Message 2: UV - Poly - Mylar Tape
from Bill
Message 3: Re: UV - Poly - Mylar Tape
from Marc & Marcy
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Subject: Re: UV - Poly - Al Tape
From: Adriana Gutierrez & Dennis LaGatta
Date: Sun, 30 Jan 2000 01:58:20 -0500
> *Twenty years ago, my uncle ran 3M. As I passed thru' town, he gave me a roll
> of aluminum tape, (self sticking, no duct tape) and I think I've seen it in
> automotive body repair supply businesses.
This self-stick tape is available at Home Depot in the section that
sells the reflective "bubble-wrap" insulation. I wonder if reflecting
the light back through the film will degrade it because of the
"double-dose" of light concentrated over the pipes. A second
consideration is Emmett's warning about right-side and wrong side of the
film. You are reflecting the light back through the wrong side.
Adriana
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| Message 2 |
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Subject: UV - Poly - Mylar Tape
From: Bill
Date: 30 Jan 00 10:00:03 PST
Subject: Re: UV - Poly - Mylar Tape
(Good point on UV, Re: White PVC reflectivity,
similar to aluminized tape Vic.)
Bill wrote:
> If merely covering the PVC w/something like vapor
barrier and duct tape as a fastener -
*This morning a probable covering occurred to me.
The issue is contact/near proximately of thge poly
to PVC due to outgassing contamination of the PVC
to the new poly formulation.
So contact/immeadiate proximity is the issue and
perhaps covering merely the contact portion is
adequate, or 1/3 - 1/2 the circumference.
(Removing the "wrap" work. And IF you "wrap,"
several linear strips is less work, AND results
in less linear overall seam length, to leak gases.
Thus a tape good for this would be mylar. Whether
aluminized or not. This is used for mylar balloons.
(To include satellite balloons.) Resistive to helium migration/permiabili=
ty. =
The reflective coating is
not the low p portion. This is why they last days
with helium, as opposed to the hours of latex balloons.
It is used for high voltage transformers. It is
quite thin. Commonly yellow, in the electronics
industry. Very tough and stretches somewhat but only
somewhat, due primarily to it's extreme strength.
Any nick tho' and it will tear readily.
We used it to insulate standard transformers and
power supplies in endoscopic equipment for medical
grade applications, (6KV.) Lamps used were arc lamps
and their output was filtered, but caused copious
quaniities of UV/ozone before the filter was encountered.
Everything rubber or plastic lasted a very short time.
Mylar is impermeably to ionic electron transfer as
well as small element gasses, like helium. It is
extremely non reactive. Sensitive to significant
levels of heat, as most tapes/plastics, but fine
at any temp PVC will handle and then some.
Transformers get hot!
A side benefit is it's extremely smooth tough surface.
This should add some life to the poly due to low abrasion
during any winds moving the surface.
Bill
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Subject: Re: UV - Poly - Mylar Tape
From: Marc & Marcy
Date: Sun, 30 Jan 2000 11:49:37 -0700
Bill wrote:
>
> Subject: Re: UV - Poly - Mylar Tape
> (Good point on UV, Re: White PVC reflectivity,
> similar to aluminized tape Vic.)
>
> Bill wrote:
What about Hypalon? Reason I mention that is that haystacks
all around here are covered with old Hypalon billboard
advertisements. It's a freebie or cheapo resource at worst.
I remember the rolls of Mylar, Kapton, Teflon etc.
insulation tape I would use in the lab and the looks (like a
dying calf in a mud hole) I would get when getting
purchasing approvals. Stuff's not cheap (darn it).
Marc
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