While doing some research trying to find out more about the Japanese PVA (polyvinyl alcohol) containing laundry starch that is supposed to improve bubble color so much, I came upon the following abstract from a patent application at http://www.freepatentsonline.com/y2006/0076539.html and I wonder if there are some clues here for making bubbles. My reading about the Japanese laundry starch is leading me to think that it is the modified rice starch + PVA that is responsible rather than PVA on its own -- as everyone that I have spoken to that has tried straight PVA as an additive has given up on it.
Bubble solution formula and method of manufacture United States Patent Application 20060076539
An improved bubble solution for use with bubble blowing wands or toys and the method of manufacture is disclosed. The bubble solution contains water and functional amounts of EDTA-2Na, propylene glycol, lauryl betaine, a natural starch (such as Natrosol™ 250HHR), and a preservative (such as Phenova™).
The bubble solution is made by (1) heating de-ionized water in a mixing tank; (2) adding EDTA-2Na and the natural starch into the hot water and stirring until the solution is uniform; (3) mixing propylene glycol, lauryl betaine and the preservative in a separate container until uniformity is reached; and (4) pouring the solution from step (3) into the mixing tank while the water is still warm and the natural starch is dissolved. The bubble solution according to embodiments of the present invention produces more bubbles than presently available bubble formulas, using the same wand and same air pressure.
SEE THE LINK ABOVE to see the full application which contains the recipe. It appears that they are calling Natrosol 250HHR a natural starch even though it is a kind of HEC (which is a modified cellulose gum rather than a natural starch -- if I understand correctly). The patent application includes a recipe which might be an interesting jumping off point for people experimenting with homebrews.
There is another presentation of the same application information at: http://www.freshpatents.com/Bubble-solution-formula-and-method-of-manufacture-dt20060413ptan20060076539.php