Solar disinfestation pillow
This arrangement does not require making a rigid frame. Therefore it involves a bit more careful heat sealing
than does the plenum frame, but when deflated, the pillow can be stored in a much smaller space. As well,
many of these pillows can be easily constructed. It is just as efficient as the plenum frame. However it is
vulnerable to windy conditions; therefore, tying a pillow to stakes using a strong line is advised.
Cut four sheets of 3 mil polyethylene, two
clear and two black, and stack them as follows: Heat seal a clear sheet to an adjacent
clear – black – black – clear, as illustrated. black sheet along one edge for both top
and bottom pairs of clear and black sheets.
(A doubled layer makes an inflated cavity just below
the greenhouse cavity that will smooth out spikes
in temperature from solar gain over the object. This
starts with a six-layer stack of plastic sheets: clear –
black – clear – clear – black – clear. Create additional
taped inflation seals inside the object cavity. Slide the
object between the two inner clear sheets.)
Heat seal all four sheets together
on remaining three edges.
As with the plenum frame, the pillow is oversized
so the shady side can heat up (due to transferred
radiation that has bypassed the object).
Heat sealing without a specific tool can be done by
using two sharp-cornered bars of aluminum angle, a
few strong spring clamps, and a small gas torch. Clamp
plastic between angles and slice to within 2 mm of the
angle bars with sharp scissors. Weigh down loose sheets
with planks to prevent them from being lifted by the wind.
Quickly pass flame along the protruding edge of plastic
until it rolls together. Do this outdoors, away from
combustibles, and protect yourself from any plastic
fumes. Before removing clamps, ensure the seam is not
burning. Properly done, this allows fast assembly of sheet
films, and will form a strong bead seam that is airtight.
Figure 20. Solar disinfestation pillow.