Читать книгу More Straw Bale Building - Peter Mack - Страница 63

You want your bales tight. Bales can be tied with polypropylene string, sisal twine, or metal wire. Any of these options is fine. It is the solidity of a straw bale that allows it to be used as a building material, and that solidity — or lack thereof — is a direct result of how tightly the bale has been tied. A farmer can adjust the baling machine to vary the tightness. Really tight bales use less twine or wire to bale an entire field but are heavier and harder to handle. If you are preordering your bales, be sure to specify that you want them on the tight side. But what exactly is tight?

Methods for assessing tightness vary from the low tech to the scientific. For the low-tech method, pick up the bale by its strings and check that they don’t lift from the bale by more than five to six inches. The bale should also maintain its integrity if you lift it by just one string and shake it around. If it spills out when you do this, the bales are too loose. Be sure you sample a number of bales from different places in the stack.

Some attempts have been made to more scientifically quantify tightness. The Arizona and California Straw Bale Codes specify that bales shall have a minimum calculated dry density of 7.0 pounds per cubic foot. This requires you to weigh, measure, and record the moisture content of the bales. If you are in serious doubt about the bale quality, these figures may be useful to generate. But don’t forget, the farmer has likely been around bales for a long time. He or she will understand the concept of a tight bale, and their opinion can mean as much or more than your calculations.