Monday, October 11, 2010

Nylon for Jewelry... Bonded or Waxed?

And more about bond than you probably want to know...

Nylon #18, a cord made originally for upholstery, used to be available waxed or bonded in the USA, but sometimes in the late 70's the waxed variety was mostly discontinued. Bonded nylon is better when used in industrial sewing machine. 

Nylon was originally invented in 1935 by Wallace Hume Carothers at DuPont as an alternative to silk for stockings. Nylon is a continuous fiber similar to filament silk. Continuous filament fibers makes nylon thread and cord very strong. Polyester on the other hand is a spun fiber mimicking cotton with shorter fibers spun into thread. Spun thread or cord is usually less strong, has more stetch and breaks more easily when pulled. This makes cotton or polyester good choice for sewing as the thread are less slippery. For jewelry making, silk and nylon are better choices when no stretch is desired.

Waxed cord is a bit easier to knot but harder to un-knot than bonded cord. There is a learning curve, for example for tying double half hitches in Cavandoli knotting with bonded cord versus wax cord, but once it is mastered bonded cord is a better choice. 

Advantages of bonded versus waxed nylon
  • Better abrasion resistance
  • Easier to undo knots
  • Bond outlast wax
  • Wax is allergenic
What's bond? What is it all about?
Here is the explanation from one of the C-Lon factory expert. 

It is a polymer coating applied the cord or thread after it has been plied, then heated and dried in ovens. The bond coating is critical in keeping the 3-ply cord together. It hold all the nylon filaments together and adds durability with a tough and smooth protective coating. Afterwards to make the cord stick together and hold its shape on the bobbin, tack is applied to the cord. 

The bond is essential for working with beads and for jewelry making, but of course how much bond is desired is a complex question... More bond creates a stiffer cord... Less bond makes a softer cord.

A consistent bond quality is essential to a cord brand. Drastic changes in bond levels can be a real problem. This is what happened with Conso Nylon #18. The newer supply had a drastically lower bond level than the older supply and the newer dye lots did not match previous ones. Everyone was returning the new supply and Conso discontinued manufacturing bonded nylon.

Bond whitening 
When the bond or tack experiences friction or abrasion, it will go from its transparent form to more of a white/grey color....think of cooled wax. When you break a colored candle, at the crack or breaking point you see white in the color. This whitening is going to happen with all colors but shows up more in the dark colors and is almost impossible to completely avoid. It can be worse when the bond level is on the heavy side and it is more noticeable on darker colors. 

Bond whitening occasionally happens with new cord production. It seems to occur in the middle of the summer or winter... and might be due to extreme temperatures differences when the cord was shipped. 
I have mainly seen this whitening of the bond with some of my older bonded nylon spools stored for a long time in a garage. 

Heavy manipulation of the cord can also produce whitening of the bond. 
For example, I noticed that square knot braids held up next to double half hitches were not as dark even though they were knotted with the same color. But when applying the fix below, the colors matched again...

Bond whitening - How to fix it
To fix this, simply rub a lint free piece of fabric soaked with isopropyl alcohol across the thread or cord. The alcohol activates the bond back to its translucent form.
I use lens cleaning cloths.

I have been making jewelry with bonded nylon and silk all my professional life. My very first pieces were made with waxed cord. Some of my pieces in my personal collection were made many years ago and have been worn extensively. Other than a slight fading and an occasional washing, they are in remarkable shapes.

In 2005 after a disruption of bonded nylon supply, I started an online supply store specializing in bonded nylon and silk thread & cord for my students. - Marion


Sheri Oz said...

I very much appreciate your detailed explanation. Since you wrote this over ten years ago, I wonder if there has been any change in the bonded thread over this time? I am thinking of switching from waxed thread because I mainly make bracelets and the slip knot start slipping while wearing after a few times.

Marion Hunziker-Larsen said...

The waxed cord or thread are still manufactured the same way today. There has been an uptick of jewelry made with waxed Brazilian polyester. Personally I would stay away from that thread for jewelry making.