back to
main

I used 1.5 mill metallicized nylon blimp bag material. Mylar should work the same way.

The first step is to lay the material flat on a large surface and fold it over in half, shiny side out. I used books to help flatten it out. I put paperclips at 6 inch intervals along the seams to hold the material in place.

Seal one the long open sides first. You can use a standard household iron heated to 250-275 degrees (the polyester setting on my iron) to seal the seams. I placed a ruler one inch from the edge and ironed against it to keep straight.

Be agile and quick! the iron should not be in contact with the material for more than 3 seconds at a time. Iron each seam a few times. The material changes visibly when it is sealed.

Now test for leaks by filling the bag with air. You can use an automatic air pump or the exhaust end of your vacuum.

Close the air spout by folding it over and taping it in place with packing tape. I also cut a thin piece of cardboard and folded it over the spout, then paperclipped it in place to tighten the seal.

Let the bag sit for an hour or so and if it hasn't lost volume you're set. If it has, try to spot the leak and patch it, then test again...

At this point it should look like a cyber pillow:)

Finally, if you passed the leak test it's time to inflate!

First deflate the balloon (use the other nozzle on your air pump or vacuum, don't wait for it to deflate on it's own unless you are extremely patient).

At this point I ironed on an extra scrap of material to use as a hook to tye a ribbon to for grounding the balloon. Whatever you do, don't let your hard work fly away on you!

Insert your helium nozzle and gently, slowly fill until almost full, but be careful not to overfill or it could burst.

Up and away!