Gelatin as an additive[]
Based on a suggestion from Cobutterfly in this thread, I have had a couple of sessions using a mix that includes gelatin as well as guar gum as Cobutterfly has had success with gelatin extending the life of her bubbles. I am not having such good luck. Indoors with the Longevity Test setup, the bubbles have a similar average life expectancy as guar gum juice at the same dilution. Occasionally, a guar/gelatin bubble lasts noticeably longer but there are also some premature poppers.
I am experiencing a similar result outdoors with a tri-string -- although the difference is more pronounced. With the guar/gelatin mix, there have been a considerable number of times where I couldn't get the wand (70" top-string) fully open under calm, cool, humid conditions. The guar mix under those conditions was working fine.
Perhaps, the gelatin only works well when it is hot and dry. As it is, the mix is very viscous. Perhaps it needs heat to reduce the viscosity and improve the flow rate.
So far, I haven't had hot dry conditions under which to compare. One hot/dry day was too breezy to get a meaningful read.
Today with 65F and 75% humidity, the guar alone worked much better. The gelatin mix is noticeably thicker with thicker bubble walls. Adding detergent to the gelatin mix helped a bit, mixing with the plain guar mix seemed even better but I couldn't compare that mix to the plain guar mix due to time constraints
Perhaps, less gelatin needs to be used when using guar?
I need to find out if User:Cobutterfly used a gelatin/guar mix successfully. And if so, how much guar she used and what the water:detergent ratio was.
My mix was the 'standard' guar mix plus 4 packets of Knox gelatin added as Susan suggested. The gelatin was dissolved in 6 cups of the recipe's water which was boiled. The gelatin water was allowed to cool to 80F before combining with a guar/water mix made with the rest of the water.
Update Oct, 3, 2013[]
I brought the gelatin/guar mix, some Uncle Bubble Ultra Concentrate (diluted 9:1), and some standard guar mix to a park playdate. The temperature and humidity were about 75F and 35% respectively. I brought a variety of tri-strings and nets. With the kids' tri-strings 20-22" top-string wands (top-string full-ply rayon mop yarn and the bottom-string a single ply), the gelatin mix was creating 2 foot diameter bubbles that on-average lasted a noticeably longer time than the standard guar mix. However, the juice that contained the gelatin required more care in getting the bubbles closed than the juice without it. With a large tri-string (70" top-string), the gelatin mix was much more difficult to use. The film often broke before the wand was fully-opened. The general impression was that the skin was weaker. Perhaps it is due to the high viscosity of the mix.
Maybe gelatin and guar have compatibility issues or perhaps, the amounts need to adjusted so that the mix is not so viscous. It will be interesting to try the gelatin with PEO since the PEO does not increase the viscosity by a large amount. Or perhaps with guar but reducing the amount gelatin and/or guar.