Originally Posted by GarciasHomeBrew
jest get the longest 4x4 you can and put it in the grond 2-3' with an Eye Screw at the top. then tie the twine to the eye screw then down to the plant.
im not sure buy dosint the sun make PVC brittle?
The Effects of Sunlight Exposure
The exposure of PVC to the UV component of
sunlight results in PVC molecules in the first
.001" to .002" of exposed surface becoming
permanently converted to a complex structure
typified by polyene formations. The result is a
brownish discoloration, often termed “UV
Discoloration,” “UV Degradation,” or simply
“Sunburn.” UV discoloration does not occur
where PVC is not exposed to sunlight, and
ceases when exposure ends.
The discoloration process is time dependent, and
can be slowed with the addition of UV absorbers
in the PVC compound. The most common
additive used for this purpose is titanium dioxide,
which also functions as a pigment. Titanium
dioxide imparts a beige to bright white color to
PVC compounds, depending upon the type used.
The Consequences of Sunlight
Exposure for PVC Pipe and Conduit
Research has been done to determine the effects
of long-term (two year) sunlight exposure on PVC
pipe (See “UNI-TR-5: The Effects of Ultraviolet
Aging on PVC Pipe,” by the Uni-Bell PVC Pipe
Association). Other than the visible discoloration,
the following summarizes the results on pipe
Physical Property Performance Characteristic Effect of Sunlight Exposure
Impact Strength = Decrease
Impact Resistance = Decrease
Tensile Strength = No Effect
Pressure Capacity = No Effect
Modulus Pipe Stiffness = No Effect
The research indicates that the sole performance
characteristic adversely affected by sunlight
exposure is impact resistance. Depending upon
the type of pipe, additional care may be required
during pipe handling and installation to avoid
potential breakage. Once installed, however,
there will be no effect on the pipe’s pressure
capacity and external load capacity.
The degree to which impact strength is affected
by sunlight depends upon a number of variables,
including: time of exposure, climatic conditions,
diameter of pipe, wall thickness of pipe, and type
of PVC compound used. Because of these
variables, it is impossible to state how long it will
take before the effects of sunlight exposure
become noticeable. In general, pipes of smaller
diameter and thinner wall will exhibit more effect
from sunlight exposure than larger, thicker-walled
pipe. The effect of sunlight exposure on thickwalled
pressure pipes such as those made to
AWWA C900 and C905 is almost unnoticeable,
other than the surface discoloration.
The tapping of UV-discolored pressure pipes has
been a topic of concern. However, the PVC pipe
industry has found no evidence of tapping
failures due to UV discoloration.
PWEagle’s Schedule 40 and Schedule 80 UL
listed electrical conduit has been tested for
sunlight resistance according to UL requirements
and is listed for continuous outdoor exposed use.
Prevention of UV Discoloration
For permanent above-ground PVC pipe
installations, it is recommended that the pipe be
protected from sunlight exposure. This can be
accomplished by wrapping the pipe with an
opaque material, or more commonly, by painting
it. If the pipe is to be painted, a water-based
latex paint formulated for exterior use is
recommended. Oil or solvent-based paints may
damage the pipe and/or not adhere well. In order
to minimize heat build-up, white or light-colored
paints are best.
Pipe that is going to be stored for a long period of
time (one to two years or more) may be protected
from the sun with light colored tarps. The tarps
should be placed so as to allow for adequate
ventilation to prevent heat build-up.