How Many Passes Do I Need to Make on the Drum Carder?

One of the things I love about using a drum carder to prepare fiber for spinning is how easy it is to blend different fibers and colors. When I first learned to use the drum carder, the "rule of thumb" was that you needed three passes on the drum carder. While I found this to be true when processing fleece, I often want to combine colors and textures from commercially prepared roving. Would I need to follow the three pass rule if the fiber has already been perfectly aligned?

Generally, the more times you put fiber through the drum carder, the more thoroughly blended the fiber will be. Other things affect the blending too - like how many layers of color you use. In the photograph above, both balls of roving have been through the drum carder once - but how I fed the fiber in made a huge difference. On the left, each color was fed in as a single layer. On the right, I alternated colors frequently, which resulted in much more blending from the first pass. 

In the photograph above, you can see the progression of blending. On the left is some roving that has been through the drum carder once, with each color fed in as a single layer. In the middle, the roving has been through the drum carder twice, and on the right, the roving has been through the drum carder three times. In this experiment, there wasn't a huge difference for me between the fiber that had been through the drum carder two and three times.

So how many passes do you need on the drum carder? It all depends on what effect you're trying to achieve in your yarn. Stay tuned to see how each of these spins up!