last changed : 01/10/2003

Note : 1 meter = nearly 3 ft (3,28 ft), 1 yard (1,093 yard) or 39 inch (39,37). Measure are decimal in this page (1.5 ft = 1 and a half ft)

Required hardware :

- a roll of thin rope or sail sewing wire : the kind of wire available at the butcher shop is also good.
- 42 m of black plastic available in huge tube of 1,5m (5 ft) half perimeter
(you need more if you want to optimize the cutting waste building a second balloon)
- the characteristic chart and dimensions chart for a 4m (13 ft) diameter balloon (the xls file Ballon de 4 m de diamètre),
- a "basket" : a flower pot or a tin can ; plastic box or what ever else.
- a piece of plywood 5 mm thick (100x12) or (better !) a table 7 m long et 1,5 m large, 6 m de Kraft paper de 1 m large.
- a room more than 7 m long !
 for more information check the page  : Required hardware (in french)

Building Time: 3 to 6 hours with 2 peoples.

For a single person it is difficult and, above 2 people, the others are only giving useless advises !

Process :

0 - Pickup the dimension chart or the xls file Ballon de 4 m de diamètre.
1 - Prepare your working space : Clear an area of ground (or cover the table with brown paper (Kraft paper is best). It does ease the cutting with the hot iron or rope cutter). Be careful using the cutter or the electric rope cutter.
2 - Cutting the strips : Lie down 6 layer of plastic. Get rid of any air trapped between the layers.
Respect the D10 cell value in the xls file: "longueur d'un fuseau" (6,9m for a 6 strips balloon x - 9,65m if you want to optimize the cutting waste building a 2nd balloon ). Maintain the strips lined up together using clothes pin. The plastic been double, that make up 12 layers. (figure 1)
3 - Drawing : Draw using the white corrector the mark 0 at 5 cm of an end. Then Draw a mark every 25 cm on the edge of the plastic write the distance to the top every meter (1, 2, 3, etc.).
4 - At each mark, write with the corrector the 1/2 width of the strip.

5 - Assembling without soldered joint : Cut the plastic pieces following the reference marks using a good pair of scissors.
6 - Put side by side both piece with an overlap of: 2 mm to 5 mm. assemble it with adhesive tape. One people will hold the pieces while an other one will put the adhesive tape.
Warning ! you need to cut the non used ends of tape ( else it will stick anywhere on the plastic and it can't be peeled off without tearing up the plastic).
Warning ! the vertical tape (running from bottom to top of the balloon) must be of one piece. No assembling even with a large overlap
7 - Do it again until the envelope is finished.
8 -Turn inside out the balloon continue this process from ref. point 12.
This process does have one drawback : the glue of the tape soften when the heat reach around 40à 45°Celsius. So there is a risk that the balloon might tear itself apart if the envelope temperature reach or exceed 40 à 45°Celsius.
This risk is greatly reduced if you do your testing during cold weather....

5 - Assembling with soldered joint : Cut the plastic pieces following the reference marks using a good hot iron.(figure 2). If you are on the ground put a piece of plywood 5 mm thick underneath the cutting zone in order to avoid burning the ground. Line-up the ruler to 3 reference marks. Push strongly in order to maintain the layers squeezed together. Cut small segments moving the ruler and the plywood meanwhile. Try to adapt the cutting speed to the best suited. Hot cutting will also solder all the layers together. Get rid of the unused part or salvage it for a second balloon.

6 - Cutting the bottom of the balloon : to make the vertical piece the same size, cut with scissors at thelength corresponding to the: cell D10 ("longueur d'un fuseau") - 10 cm + 2,5 cm (reserve for reinforcement). Get rid of clothes pin.

7 - Making the vertical tape (running from bottom to top of the balloon) : Open leaf 1 and put (from the bottom of the balloon ) the 2 in wide parcel adhesive tape on the joint in order to reinforce it between 1B and 2A. .A is the right side, B is the left side (fig.3).
Warning ! you must pull on the plastic in order the adhesive being the closest possible of the joint . You need to cut the non used ends of tape (else it will stick anywhere on the plastic and it can't be peeled off without tearing up the plastic).
the vertical tape (running from bottom to top of the balloon) must be of one piece. No assembling even with a large overlap.
In the most curved part of the profile, you can use a big bag filed with sand or what ever to make a "curved top table" in order to ease using the tape.

8 - Open leaf 2 and "tape" between 2B and 3A (fig 4). Continue that way until before the last leaf. You have made 5 tape junctions. Make one junction less than the number of leafs (fig 5).

9 - Go back to leaf 1 and "tape" between 1A and 6B (fig 6).

10 - Separating the leafs (fig 7 and 8) : This is more difficult grab leaf 1B and 2A (both leafs are tape reinforced) between thumb and the index finger the closest possible of the joint and hold the joint with the other hand. Pulling slowly, the leafs 1B and 2A should tear neatly from the joint while remaining assembled by the tap . Do it again inch by inches.

It may happen that the black plastic tear of, if so put it back on tape and go cautiously.

11 - As soon as the leafs 1B and 2A separated of the main joint on 1/2 meter long, do again the same with the other leafs. Continue so from 1/2 meter long to the next 1/2 meter long. There is 42 m to tear off, but it must be done slowly neatly and the closest possible of the joint. Go by short length pulling inside out the balloon.

12 - to reinforce the bottom of the balloon. Use the following process :

13 - Cut 6 length de 1 meter of string to make the basket wire. The basket wire are tied on the bottom end of the balloon on each tape of joint between leafs. Punch a hole above the reinforcement wire (running around the whole bottom opening of the balloon). Put the basket wire through this hole and tie it on it self and around the reinforcement wire.

14 - Tie the basket to the remaining end of the basket wire. Adjust the lengths. You can add one more string ( a long one 200 meters or less )in order to hold the balloon on captive flight.

15 - Your balloon is ready !

16 - Important HAVE A LOOK AT "Use a 4m (13 ft) diameter solar balloon" and check the rules relative to your country !

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