I didn't think to look at Wal-Mart for large boxes of gelatin packets. Now I will.
I don't usually time these things...
Maybe I should!
I know I have left them on for longer than 5 minutes. With the Aphogee 2-step you actually blow-dry the PT on your hair with high heat until it's dry and hard. This does't take me long, but it's a big dose of heat.
When I started using Aphogee, I discovered that my hair began stretching like rubber bands rather than snapping off. It got shinier and held the waves better. This is the result I look for in a PT.
I have used this recipe blow-dried in with epsom salts, and glopped on with banana in the mix without any attempt to increase the heat (forgot plastic bag/cap), and with plastic and a warm towel. All seem to work with the blow-drying and epsom salt leaving more frizz (naturally). I think heat is better than no heat.
Heat has the potential to speed up any chemical reactions taking place -- positively charged proteins sticking to negatively charged hair. The acid helps keep the charge on the proteins (that is kind of an oversimplification, but whatever).
At some point, all those sites that can bind the protein will have already bound some protein and the rest is just going to have to wash away. So if you get good results with 5 minutes, great. You can try 8 or 10 or 15 minutes and if that seems even better, great! It's your hair, you are the best judge of how it responds.
But the hair can only hang on to so much protein and once you find the right amount of time for your hair, stick with it.
Glad it worked well for you this time! Never had a problem with rinsing out unless the gelatin isn't fully dissolved.
Frequency: I can do this twice per week, although I don't see the same change as if I only do it once per week. My hair is very fine and it likes the protein.
See what works. Trial and error is tedious, but we learn a lot more in the process.