Dental Floss – Myth-buster Edition
Contrary to popular belief, dental floss is NOT a good choice to use as thread to repair gear in the field. While floss is readily available, an understanding of what dental floss is will help explain why it’s not best for sewing.
There are several types of dental floss, monofilament and multifilament, but remember, all floss is designed to be used once and discarded. It does not have a high abrasion resistance factor and so breaks down easily; Have you ever shredded the floss when flossing your teeth?
The most common type of dental floss is Nylon, multifilament floss which is made with varying numbers of filaments or threads per strand. The filaments are loosely twisted 3 – 4 twists per inch – to form the strand – and so are quite weak. Next, they are coated with a variety of chemicals and often waxed. The wax may increase the strength of the thread, but the other chemicals used to treat and flavor the threads are a total unknown factor and could affect the longevity of the floss.
Another type of multifilament floss is “Super Floss”, which is a ‘thicker’, woolier type of floss that stretches and thins. Again, the floss is loosely twisted and therefore weaker – a tighter twist will give higher strength.
Mono filament floss – such as the Glide Brand – is made from PTFE (Teflon). It is a thinner, ribbon like floss that is easy to use in your mouth, but won’t hold up well under stress of gear repairs.
Gear repairs are usually required in areas that are subjected to stress and abrasion – hence the reason they failed in the first place. A better choice for emergency repairs of gear is to use a nylon beading thread called Nymo.
Nymo is a monofilament nylon thread made for beading. It is stronger than you would ever really need it to be and costs about $2.00 per bobbin (64 yards of thread). It is available in different thicknesses, though size D is the most common.
I have been unable to locate any definitive specs on the breaking/wearing strength of either dental floss or Nymo thread, but from personal experience in using both as a gear repair thread, dental floss gets a big thumbs down.
My ‘emergency kit’ for hiking includes a partial bobbin of Nymo thread, a single edge razor blade wrapped in cardboard, with a hand sewing needle taped to it. All of this fits into a tiny plastic box the size of the razor blade (sewing pins come in these little plastic boxes) and a rubber band is used to keep it closed. When the shoulder strap on my pack was tearing away from the pack, I sewed it with Nymo thread and hiked another 250 miles without ever worrying about a failure. I’ve also sewn my pants when the seams were failing due to really cheap thread used in their construction.
In addition to being perfect in repairs, Nymo can also be used as dental floss in a pinch. (Yes, I have also used it as floss!). And, yes, that is a small roll of dental floss - I store it here becasue I don't bring the bulky plastic container it comes with, and I need the razor blade to cut it!