There are two reasons to consider using the polypropylene high strength pulling twine instead of 14 gauge wire for making the blocks. First is because the twine is so much easier to work with than the wire. No special tools are required and it is less physically demanding. The second reason is the cost. The 14 gauge wire can be purchased in Haiti for $80.00 for 5,800 feet (100 lb coil). 6,500 feet of the twine can be purchased at Home Depot for $39.95. We can buy it in bulk, 1,000 lb minimum, for $.0001per foot or less. The polypropylene isn’t strong enough to replace the wire in the construction of the house but it is more than adequate to replace the wire in building the blocks.
The twine is cut into lengths 66 inches long. A loop knot is tied in one end. The knot is used to locate the twine in the end plate of the Ubuntublox block making machine. The twine is placed inside the spaces in the bottom of the machine just like the wire. Sometimes the twine is difficult to place in the space. I have found using a stick or piece of wire to place the string in the opening helps.
After the block is compacted and the covers are opened up the twine is used to secure the block. No special tools are required. I have found that a wire bent with an hook on one end makes pulling the end of the twine through the end of the machine very handy. My wife watched me fight it and then told me I needed to make a tool that was like a hook out of wire. I did as I was told and once again am glad I have such a smart wife.
The end of the twine is placed through the loop and pulled tight by hand. The twine is too strong to be pulled apart by hand. But pulling the end too tight can cut the loop. It needs to be pulled tight but not too tight. The block is already compressed into shape and the twine is supposed to hold that shape. The twine isn’t supposed to compress the block further.
What I have found that works well is to pull the end through the loop and then place a finger over the connection of the end of the twine and the loop. This will secure the twine in place while a half hitch knot is made. Once the first half hitch knot is made then the finger can be removed and a couple of more half hitch knots can be added. http://www.animatedknots.com/halfhitch/index.php
I secure the middle twine first and then the ends.