and my mother’s aggravation over the disappearance of yet more household supplies —
aka “engineering materials.”
We went on to fly more balloons (tethered),
one even carrying a half-pound camera aloft.
Years later, I bought and flew a ready-made
model hot air balloon with my son. While
more colorful to look at, it didn’t fly nearly as
well as our homemade versions had. For all
you readers who enjoy that special kick that
comes from seeing an unusual homemade
rig actually work, here’s some fun that can be
had on a kite-string budget.
FOR THE BALLOON
Painter’s drop cloth, 0.7mil plastic, 9'× 12' (3m×4m)
Wicker or small-diameter hard plastic pneumatic
tubing, 5' ( 1.5m) or similar
Transparent tape, ¾" (19mm), 1 roll e.g. Scotch tape
Duct tape a few pieces
Twine, lightweight cotton, 300' (100m) or similar
for the tether line, not susceptible to melting
Cardboard or wax paper to act as a separator in Step 1
FOR THE BURNER
Stovepipe, aluminum or black steel, 6" (150mm)
diameter, a few feet
Heat register box, aluminum or heating duct elbow,
or scrap sheet metal, for the firebox
Screen, metal, about 6"× 6" or slightly bigger
My original balloons were fashioned from two
9'× 12', 0.7mil plastic drop cloths, seamed
together into a cylinder along their 12' sides.
The finished envelope enclosed a volume of
roughly 230 cubic feet ( 6. 5 cubic meters),
weighed 15oz (425g), and would lift again as
much in payload when thoroughly heated.
Unladen, these balloons had lots of extra lift
for rapid climb and a long flight before cooling
enough to descend.
The single-drop-cloth balloon presented
here encloses about 75ft3 ( 2.1m3), weighs
about 8oz (227g), and will provide another 4oz
(113g) of extra lift when heated to the plastic’s
safe capacity. These smaller balloons provide
shorter flights but are much easier to handle.
1. Make the balloon envelope.
Lay out the drop cloth on a smooth, clean
floor. Place a strip of cardboard or wax paper
(a separator) on top of the drop cloth, running
down its centerline, parallel to the 9' sides.
Fold the 9' edges over so they meet on top
of the center separator (Figure A). You may
find it helpful to first place a strip of tape,
sticky side up, in the center, then draw the 9'
edges to meet at the tape so the edges are
abutting and parallel.
Tape the edges together to form a 9'-long
cylinder, trying to overlap the tape evenly
onto both sides of the seam (Figure B).
Goofed spots can be double-taped later. The
separator may now be removed.
2. Close the top.
At one end, gather in the plastic as evenly
as possible from points every
1 of the way
around. Twist tightly together for a few inches
and secure soundly with tape or a couple of
twist-ties or zip ties (Figure C).
3. Make the inlet.
Form the tubing into a hoop about 1½– 2'
in diameter and splice it with duct tape. For
springy materials, reinforce the tape with zip
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