that "sweating" design I have had happen by accident. It comes from bubbles forming under the disc. This is different than the bubbles under the vinyl that people push out with a credit card. I am referring to dipping your disc too early after mixing your rit and water and there is a foam or bubbles on the surface of your liquid.
Second way I have had bubbles is by using a crappy pan and heated rit water. As we all know, if you heat your water enough you will see steam, which is really water vapor or water evaporating. A crappy pan with cuts or rough spots on the bottom serves as bubble formation points, much like how C02 bubbles form so quickly (and violently) on mentos tablets when dropped in diet coke. (the mentos tablets have tiny pores or craters on the surface that allows bubbles to form and take shape by the thousands). So when your water is heated, especially by stove-top where the bottom of the pan is the hottest, water will start turning to gas and bubble up under your disc even if you started out with a nice flat pool in your pan.
