On a recreational trip to home-depot, I came across .31mil polyethlene sheet that came in 12' x 400' rolls. WOOHOO!

The garage floor was quickly swept and a ~1000 cu ft balloon with arbitrary drawn gore profiles was thrown together with packing tape along the seams and a MSR Wisperlight at the bottom. We now had appreciably increased lift capacity, and road flares naturally took the place of fire crackers.

The .31 mil painters plastic, being purposed as a floor condom, does not have very high tensile strength. We were battling holes that would open due to un-even manufacturing, or just too much stress. Of note, we did not (and have not yet) ran into temperature issues as the inner envelope temperature does not have to be too high when it is 40 below out.

Anyways, That got me reading into natural balloon design, and I came across a plethora of figurin' and past experiments. of interest were Justin Smalley's reports and then the stuff that Raven Industries did for the navy.

http://www.ballooninghistory.com/raven/finalreport/

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My Experiments with Hot Air Balloons.
My name is Patrick Dewane, and I study engineering at the University of Alaska, Fairbanks. Last fall, I snagged a roll of "trash can liners" (fancy way of saying trash bags) from a janitor's closet, and was bitten by the balloon bug. It started by making a ring of cardboard about a foot in diameter, stapling the trash bag onto the ring in 8 equi-distant places, then wiring in a cut up soda can into the center of the ring. We would put isopropyl or white gas in the can, and send the balloon away. (at -40 C, after the point of homogenous nucleation, trash bag hot air balloons can lift an appreciable amount of fire-crackers). It then naturally progressed to building bigger Balloons. First was a refrigerator sized bag made out of squares of tissue paper. it had quite a spectacular burn-up when it entered a breeze a few hundred feet up and splashed its burning white-gas onto the envelope. Next came spliced together trash bags. kind of exciting, but they were damn ugly. On a recreational trip to home-depot, I came across .31mil polyethlene sheet that came in 12' x 400' rolls. WOOHOO! The garage floor was quickly swept and a ~1000 cu ft balloon with arbitrary drawn gore profiles was thrown together with packing tape along the seams and a MSR Wisperlight at the bottom. We now had appreciably increased lift capacity, and road flares naturally took the place of fire crackers. The .31 mil painters plastic, being purposed as a floor condom, does not have very high tensile strength. We were battling holes that would open due to un-even manufacturing, or just too much stress. Of note, we did not (and have not yet) ran into temperature issues as the inner envelope temperature does not have to be too high when it is 40 below out. Anyways, That got me reading into natural balloon design, and I came across a plethora of figurin' and past experiments. of interest were Justin Smalley's reports and then the stuff that Raven Industries did for the navy. http://www.ballooninghistory.com/raven/finalreport/ With a little math in hand, we cut gores for a Sigma 0, Lambda 10 .7mil polyethylene balloon. http://www.globalindustrial.com/p/packaging/strapping/plastic/hand-grade-polypropylene-lenght-7200-feet?infoParam.campaignId=T9F&gclid=CKbWuJ6pz70CFVJffgodj3wA_A The current plan is to laminate load tapes and gores together with hot glue, then run packing tape down each seam. Each seam takes about 3 hours to complete, and 4 are currently done. another 800ft of hot glue, and I will posses the worlds largest over-designed trash bag. Human flight should not be attempted over freezing, so a trip north, or a long wait is due. Contact me if you are interested.