Here is another tip to help make marbling fun and easy.

How to make rakes with corrugated cardboard, glue and toothpicks. These are rakes that I made for a marbling class that I taught. My students use a 8" x 10" tray. I made the rakes 1/2" smaller than the tray. One is 7 1/2" in length and the other is 9 1/2" in length.

Cut the corrugated cardboard so that you see the wavy side on the length you want for your rake. Figure out how far apart you want your toothpicks. You can mark the cardboard. Put the glue in those holes and insert the toothpicks. Stand them up with the toothpicks pointing up and let them dry for 24 hours.

I have three rakes for each length. The First is spaced one hole apart, the second two holes apart and the third four holes apart. That gives you enough rakes to create a large variety of designs. Experiment and have fun.