[FAQ Title]

[U]nfortunately, not all fibers are suited to making quality roving or batts. Here are some fiber characteristics that don't make good roving or batts and possible solutions:

[N]on-uniform Fiber - The best results are achieved when the individual fibers in a job are consistent in staple length and diameter. Violation of this simple precept causes the most processing problems and results in suboptimal quality of the resulting roving and whatever finished product is made from it. [More...]

The Solution: In the best of all possible worlds, producers sort, or at the least skirt, their fiber on shearing day so that fiber offered for sale is relatively consistent in length and diameter. Before buying a fleece, consumers should carefully inspect it to see that it is free of veg, dung tags, and other debris.

Next look at the edges of the fleece. Compare the length of the fiber staple there with the length of the staple in the middle of the fleece. They should be about the same length.

[S]hort Staple - A strong roving cannot be made from short stapled wools. A strong roving remains intact when pulled from the bump; a weak roving will part. If you compare two rovings of identical diameter but different staple length, the roving made from shorter staple will be weaker. This is because of friction, the same physical principle that dictates the amount of twist you need to make a strong yarn. See the description of slippery fiber below.

The Solution: You could blend with a longer staple fiber but that presents its own set of problems later. When roving contains mismatched staple length fibers, the shorter fiber will sometimes fall out during spinning or may be the source of pills in the finished product. Wait a little longer between shearings.

[T]oo Much Crimp - High amplitude crimp is not a bad thing. However, crimpy fibers can be thought of as little springs. As the web stretches from the doffer to the bump winder, these little springs can relax into their unstretched state. The fibers will be much more likely to relax with a short staple. A combination of crimp and short staple can make quite a nice roving if the crimp isn't too springy because the crimp increases the friction between individual fibers. Too much crimp though can make threading the bump winder nigh unto impossible because, while the carder is stopped for threading, the web between the doffer and the bump winder has time to relax. If it relaxes too much it will part or the stresses put on it when we restart the carder will cause it to part.

The Solution: Bend with a longer staple fiber or with a fiber that has less crimp

[T]oo Little Crimp - This is generally not too much of a problem. It is a contributor to the short staple and slippery fiber problems. 

[S]lippery Fiber - Getting strong roving from slippery fibers is like trying to turn a door knob with wet soapy hands. Slippery fibers are doubly difficult because not only do they make weak roving but they usually don't make good batts either. Slippery fibers simply fall off of the storage roll as they are carried around it. What we end up with is a cloud of fiber on the floor. We have experienced this problem most with suri alpaca, the so-called "suri" llama, and mohair.

Fleeces like these have a common characteristic - lovely sheen. Unfortunately, that sheen is indicative of a reduced number of serrations, or scales, on the cuticle and these scales are not as prominent. Processing relies on the "felting" tendency of the fibers. As the mechanical action of the processing manipulates the fibers the scales interlock. Because these slippery fibers don't offer as many connection points, the web leaving the doffer often cannot support its own weight. Microscope photographs of various fiber types can be seen on the Yocum-McColl Testing Laboratories web site.

The Solution: Blend with a "coarser" fiber. This has proved to be an acceptable solution to many of my customers who have me card their mohair. In these cases a modicum of sheep wool of an appropriate color is added to the mohair during a blending pass through the carder. The sheep wool adds just enough "cling"e; to make an acceptable roving. Sometimes I have extra sheep wool to add to the mohair but prefer that customers supply their own if possible.

[L]ong Staple - Very long stapled fibers can wrap around the rollers of the carder and fill the carding cloth. Once that happens the carder can no longer card. The rollers on our carder are about 15 inches diameter.

The Solution: Every lock must be cut so that the staple is less than the diameter of the rollers. Shear your animals more often.