Check the output of your SunJack at the inside/underside magnets -- in noonday sun on a sunny day in, say, San Diego, you should read an open voltage of around 1.5VDC - 1.7VDC (if you used 3 solettes in series, or 4 solettes in series where one solette is just a dummy electricity carrier) and a closed current of, well, whatever the closed current of a single solette is. For solettes of the area I am using in this project, the closed current is around 175mA, whereas the max current deliverable to a load like a rechargeable battery is around 100mA.
Now, mix up a bit of 5-minute, two part epoxy. Then, simply pour it onto the top of your SunJack card, over the solettes, magnets, and everything really -- everything on the top side (the side with the solettes), that is. Take care not to get any epoxy on the inside magnets, since these need to freely carry current to your battery, and epoxy is highly insulating.
I also like to add a rigid backing on the underside of the card, to stiffen the whole structure. Solettes are very fragile, and even an epoxy coat is not rigid enough to keep them from fracturing in many cases. I used a 1/8" thick piece of scrap acrylic just in the middle section of the bent card in this particular model.
One more note: It's best to put your SunJack on some popsickle sticks or some other stand so that the epoxy can drip off the sides of the card.
After 5 minutes of curing time, you have yourself a solar battery charger! Repeat 52 times and be popular.
Check out the video at the beginning on this instructable -- also here http://www.youtube.com/watch?v=nsX6r-_Nn6Y
-- for more details and for dark-current protection diodes and charging indicator lights. These aren't necessary if you are just charging your batteries during the day and have a multimeter to check that your system is working properly, but they are nice add-ons for the second or third SunJack you might make.
If anyone has neat add-ons (like better LED indicators for charging), or better ways to make a simple solar battery charger from scratch, please let me know and post in the comments...