Chocolate tempering is not easy to learn, and can sometimes be frustrating. Some people even resort to using confectioners' coatings (a.k.a., almond bark, imitation chocolate, pastel coatings, etc), but real chocolate tastes better. So, if you want to melt and re-solidify chocolate for molding and dipping, you'll have to learn chocolate tempering.
This can be done by a pro without a thermometer, but I'd recommend that you get a small one with a stem that has no greater than two degree gradations.
- Never get water or steam in chocolate.
- Never get it too hot (above 115°F for milk or white chocolate, and above 120°F for dark chocolate).
Either of the above could ruin your chocolate.
Here we go. First shave or chop your chocolate finely. Then, in a double boiler or similar contraption, immerse the upper pot containing the chocolate into a pot containing hot (140-150°) water, making sure to get no water into the upper pot.
Melt the chocolate, stirring and scraping the pot with a rubber spatula, until all the mass of chocolate is at least 110°F. Refresh the hot water in the bottom pot if it becomes too cool.
Then, change the water in the bottom pot to 70°F, and stir and scrape again, until the mass of chocolate loses its gloss, and becomes thicker. Chocolate should be about 84°. Then, replace water again with 100° water, and stir and scrape until chocolate is 88° for milk or white chocolate, or 90° for dark. Now, you're ready to use the chocolate for dipping or molding.
You may replace the water in the pot with 90° water for holding the chocolate's temperature while you are working with it. You can also wrap a towel, etc. around the pot to insulate it while you work. You can warm the chocolate again while using it, but not over 90-91°, or you'll have to temper it again.
Streaks, spots, or chocolate that crumbles or turns white will indicate that you have not adequately tempered your chocolate.
If you mold chocolate and it is not in proper temper, or if you have leftovers, you can remelt it and start over. If it has been ruined by water or heat, it cannot be remelted. This is something that can give experienced confectioners fits. Keep trying, and it will get better with practice.