WORK SPACE PREPARATION

Find a clean work surface large enough to lay out material, pattern, and tape gift wrapping paper un-printed side up to surface.

NOTE: SAVE WASTE AND USE EXCESS MATERIAL FOR PRACTICE.

IRONING TECHNIQUE

Use excess bag material to practice setting the right iron temperature and to practice ironing techniques. Cut out several 2" x 8" sections. Lay two pieces of practice material together with the shiny sides to the outside -- dull sides together. Set the iron on a medium setting (250-275 degrees). Each time you adjust the temperature of the iron, allow 3-5 minutes for the iron to stabilize to the new temperature. A temperature setting that is too hot will melt and damage the bag material and cause small holes. A temperature setting that is too cool will not provide a good seal. You have a good seal when you cannot pull the two sides apart easily. Wait for at least 2 minutes before you try to pull the seam apart. The bag material needs to cool back to a normal temperature before you test it.

Place the iron flat on the seam line approximately 1/2 inch from the outside edge of the bag material. With a sweeping motion pull the iron off the edge of the bag material. The iron should not be in direct contact with the bag material longer than 4-6 seconds. On the bags that have a straight edge you can use a yardstick. Practice this by placing a yardstick on a piece of practice material approximately 1/2 inch from the edge. Butt the iron up against the yardstick and with a nonstop sweeping motion, iron out and off the bag material. Each succeeding ironing stroke should slightly overlap the previous one and produce a smooth sealed seam. Test the practice piece for seam integrity, and after several successful sealed lengths are completed, you should be ready to start on your bag.

You can use one of the 2 patterns below, or make your own pattern out of heavy paper. Place the paper pattern on the balloon material and mark your fill spout. Place paper weights, small books, etc. on top to hold the pattern in place. Iron around the entire paper pattern (except for the fill spout). Then cut leaving a 1/2" seam around entire blimp bag. Re-iron the seams to insure a good seal.

1. Fold the bag material over -- shiny side out -- so that the top material overlaps the bottom material by 33". You should have two layers of bag material 33" x 38" with a fold at the top. Cut away excess bag material.

2. Use a terry cloth towel to wipe out wrinkles and remove air trapped between the two panels.

3. Lay several books or magazines on top of bag material to help keep it in place.

4. Use a yardstick and mark a bottom border 32" from the top fold line. This is the only outside border line you will have to make with the felt tip pen.

5. Place the yardstick on the left side seam leaving a 1/2 inch area exposed. Use a sweeping/pulling motion and iron a 1/2 inch seam. BE CAREFUL -- DO NOT IRON THE FILL SPOUT. The left side seam has the fill spout at the bottom corner.

6. Repeat this procedure and iron the right side. On this side you will not have to allow for a fill spout.

7. Position the yardstick 1/2 inch above the bottom pattern line. Iron the exposed material from the yardstick to the end of the bag material.

8. Cut off the extra 1" of material at the bottom of the bag -- leave a 1/2 inch ironed bottom seam.

9. Turn the bag over and mark the fill spout in the exact position as the other side of the bag. Iron this side. BE CAREFUL -- DO NOT IRON OVER THE FILL SPOUT.

10. Cut two 2" x 3" pieces of clear plastic packing tape.

11. Position tape on the fill spout on both sides of the bag. With your fingers squeeze out all excess air so you have a tight seal. This provides extra protection for the fill spout area.

12. Cut off any extra tape that extends out past the bag material.

13. Use a toothpick to separate the two layers at the fill spout so you can easily insert the helium nozzle to fill the bag. If necessary, trim taped area again so that you have a 1" fill spout opening to insert the helium nozzle.

FLYING SAUCER BAG CONSTRUCTION:

1. Fold the bag material over -- shiny side out -- so that the top material overlaps the bottom material by 38". You should have two layers of bag material 38" x 38". Cut away excess bag material.

2. Use a terry cloth towel to wipe out wrinkles and remove air trapped between the two panels.

3. Lay several books or magazines on top of balloon material to help keep it in place.

4. Tie two loops in a string that are 18.75" apart. Position one of the loops on your finger, and place your finger in the exact center of the 38" square balloon material. It may be helpful to mark the center point with a felt tip pen. Place the felt tip pen in the other loop of the string and arc out a 37.5" diameter circle on the bag material.

5. Iron an 1/2 inch seam inside of circle arc and extend to the outermost edge of the bag material. DO NOT IRON THE FILL SPOUT AREA.

6. Cut out the circle. You should have a 1/2 inch border ironed around the entire bag.

7. Turn the bag over and mark the fill spout in the exact position as the other side of the bag. Iron this side. BE CAREFUL DO NOT IRON OVER THE FILL SPOUT

8. Cut two 3" x 2" pieces of clear plastic packing tape

9. Position tape on the fill spout on both sides of the bag. With your fingers squeeze out all excess air so you have a tight seal. This provides extra protection for the fill spout area.

10. Cut off any extra tape that extends out past the bag material.

11. Use a toothpick to separate the material at the fill spout so you can easily insert the helium nozzle to fill the bag. If necessary, trim taped area again so that you have a 1" fill spout opening to insert the helium nozzle.

Bag material is available -- click here PARTS & ACCESSORIES for additional information.

FLIGHT PREPARATIONS

Testing the bag:

Place a soda straw inside of the blimp bag fill spout. Use a vacuum cleaner exhaust port and carefully blow air into the blimp bag through the soda straw. Stop filling before the bag becomes full and begins to stress the seams. Tape a 1.5" piece of Scotch tape folded over the spout opening to seal the bag closed. Set the bag aside and let it rest for an hour. If the bag does not have a leak, it will be the same size after an hour as it was when you first filled it. If the bag has a leak, locate the hole and patch it with Scotch tape, or remove air and re-seat seams that have a leak.

Storage, AND Removing Blimp Bag Air:

Place the vacuum cleaner hose on the suction port of the vacuum cleaner. Remove the small piece of Scotch tape from the fill spout and place a soda straw into the fill spout opening. Bring the vacuum hose up to the soda straw and gently vacuum as much air out as possible. Then use a gift wrapping tube and roll over the flat bag until you have removed all of the air. Roll the gift wrapping tube towards the fill spout to push air towards the opening. Place a soda straw in the fill spout so that the air can escape easily. Repeat this process several times until you have removed all the air. You can now fill the bag with helium.

When you are done flying remove a small amount of the helium. It is very important to remove some helium before storing away. Bag pressure increases with a raise in room temperature. A temperature change of 10-15 degrees could cause your bag to expand and burst. Use a clothes pin or large paper clip and anchor the blimp to a stationary object.

To permanently store your bag follow instructions above and remove all of the helium. Then, roll the bag onto a wrapping paper tube. Start at the end opposite the fill spout and roll the bag onto the tube.

Filling the Bag

DO NOT OVERFILL THE BAG. THESE BAGS ARE DESIGNED AND SIZED TO BE LOOSELY FILLED. IF YOU OVERFILL THE BAG IT WILL BURST AND CAUSE UN-REPAIRABLE DAMAGE!!!!!!

Carefully insert the helium canister nozzle into the bag fill spout. Keep the helium nozzle firm in the fill spout so air does not leak in while filling. Slowly open the helium canister valve and carefully fill the bag. CAUTION:DO NOT OVERFILL THE BAG. The bag should be loosely filled. A tight bag will stress seams and will cause UN-REPAIRABLE damage. Use only enough helium to achieve lift. Once the bag has been correctly filled, use a piece of 1.5" Scotch tape to seal the fill spout.

Helium is available at K-Mart, Wal-Mart (or similar discount store), or balloon shops in the form of a "Party Balloon Canister". This will usually give you 9-15 cubic feet of helium. You need at least 4 cubic feet of helium to fill 1 blimp bag. Then you will have extra helium to use as the helium slowly leaches out.

NOTE: If you fold over one end of the Scotch tape approximately 1/16" of an inch and make a pull tab, it is easier to take the tape off when you want to add or remove helium.

This unique item is bound to provide amusement for you, your family and friends. There are not many model aircraft you can fly safely in the house. It's very quiet, easy to start, won't knock over furniture, or scrape the walls.

Note: the most important feature of this product is the mylar bag's ability to retain helium. Treat the bag with care -- avoid sharp objects! Even a small hole can cause an aggravating "SLOW LEAK".

Helium: Get your blimp bag filled at a novelty shop, balloon shop, or card-and-gift shop. Other sources include K-mart, Wal-Mart, PriceCostco, SAMS, Target, etc. in the form of a party balloon kit/helium canister which costs approximately $20. The helium is susceptible to temperature change. Too much heat (like in your car on the way home or even in your home) can burst the bag. Make allowances for this -- if it looks like your blimp bag is stretched to tight, let a little helium out through the filler tube. The filler tube should be sealed by folding it over 2 or 3 times, then clasping it shut tightly with thin plastic or cardboard cut the width of the spout and paper clipped on. See Figure 1

Make sure you have a good seal.

Note: Cold temperatures will "shrink" the helium and give a wrinkled appearance to the blimp -- this is normal, and can be corrected by filling it with more helium or using a soda straw to blow air into the bag through the filler tube.

GONDOLA ASSEMBLY

Push the wooden dowels into the gondola (Figure 2) and use white glue, wood glue, or epoxy to keep them in place, make sure they are properly aligned, and completely dry before continuing with the next step.

Slide the propeller onto the motor shaft (Figure 2) . Position the propeller so that it does not rub against the motor housing. Use Scotch tape to attach the motor gondola to the blimp. You'll probably need a helper for this step. Line up the dowels as close as you can to the marks on the blimp. See Figure 3.

Make sure the gondola is securely attached with tape. You don't want your gondola to fall off in mid-flight!

BATTERY

Use alkaline AA batteries for best results. If you've lost lift in your blimp or live at a very high altitude you may need to resort to regular batteries. Also, if you want to add signs or something else to the blimp, you may need to use a lighter battery. The battery acts as the switch -- all the way in for "on" and pulled out slightly for "off".

FLYING

You'll need to "balance" the blimp. Insert the battery -- make sure it's in the "off" or "slightly out" position. Next add ballast until you've achieved "neutral buoyancy" . Tape on paper clips, pennies, BB's etc until it's neutrally buoyant. This can get tricky but practice with different light weight objects. Neutral buoyancy is when the blimp "just hangs there" at eye level. See Figure 4

You'll probably still need to "trial and error" test it at this point, but fine tuning it eventually becomes easy. To be absolutely technical about this, the thrust coming off the propeller will blow against the bottom of the blimp bag resulting in a downward force known as Bernoulli's principle. A very slight positive angle of attack will compensate. Point the blimp into an open area and push the battery all the way into the "on" position. You do not need to push the blimp. The blimp will now start it's voyage, taking several seconds to accelerate. It's very relaxing to watch these indoor air ships fly around -- elegantly and majestically. Some people even call it therapy. Games can be played with two or more people flying it back and forth.

You can make a tether for the blimp with thread. Make a loop in the thread at one end and tape it to the front of the blimp. Then make a loop at the other end and attach it to a pole that has a nail on one end. See Figure 5.

Visible punctures to the mylar can be repaired very easily by covering the hole with Scotch Tape or Clear 2" packing tape. It's the invisible "tiny holes" that are hard to fix -- often you can't find them.

Eventually the helium will leak out to the point where removing portions of the ballast still won't compensate. Then you know its time for a complete fill of helium.

OPEN:		JANUARY - JULY
OPEN:		OCTOBER - DECEMBER
CLOSED:		AUGUST - SEPTEMBER

John and Carol Piri WCBlimps@mchsi.com

Last updated: May, 2003