But, I have been admiring and envious the much larger bubbles that I occasionally see in videos. So, I have started experimenting with loops that have top-strings from 80 to 100 inches long. I can currently make much longer tubes with a smaller wand; but the diameter of the bubbles made with the giant loops can be quite impressive. The limiting factor for bubbles of this size is often not the loop size -- once a bubble film is stretched it starts to degrade -- and the rate of degradation is similar whether the opening is large or small. But it takes longer to open and close a larger wand, so the actual time to create the bubble is often a bit less with the larger loops. Additionally, the larger the opening, the more exposure the film has to little particles that may destroy the bubble. Lastly, the amount of juice available is limited by the size of the perimeter which increases linearly while the surface area increases exponentially (a power of 2 to be more precise). In theory, I think you need a thicker material as the loop gets bigger in order to supply a proportional amount of juice. But, that isn't practical. With a large loop (which implies long poles), the weight of the loop becomes a significant factor in terms of its handling. Also, the more inertia that the loop has (which goes up with its mass) the less responsive it is. A responsive loop is important if you want to be able to have control over when you close the bubble.
Anyway, these pictures and the video were made with a 100-inch top-string tri-string loop made of a single strand of jute twine. Jute takes up a lot of bubble juice for its weight and does a good job of releasing it. I have also been having good luck with thick cotton butcher's twine (that I purchased at Bed, Bath and Beyond).
I am theorizing that ideally it would be useful for the top-string to have more capacity than the side strings. When the side strings are less heavy, the surface tension of the bubble juice will be enough to bring the strings together and close the bubble if they are heavy enough when loaded with juice but light enough once the juice has been exhausted by the bubble. I might try making some loops with a jute top-string and a double-strand or triple-strand bamboo cord for the bottom string (the side strings).
For this bubble session, the temperature was a chilly 45F. Relative humidity about 35%. The wind was pretty brisk (and changing direction). The bubble juice was homemade jumbo juice. For my next session, I am going to try my HEC-containing blend since it might be a bit friendlier in these inhospitable conditions.