To Wax or Not To Wax
The decision to wax thread or not to wax thread is one that should be made based on personal preference. Don’t do something because everyone says to do it and they don’t explain the pros and cons, not knowing why…base it on your well thought out decision.
I personally don’t wax thread because through book repairs I have seen the ugly results of old waxed thread. Too often I’ve seen thread with yellow chunky bits falling off and the adjacent paper darkened because of dirt sticking to transferred wax, which sometimes might even be acid burning discolouration. Waxed threads came about with the bookbinding mass production methods in the late 1800s when the waxed thread added a lubricant to speed up sewing, because time is money. Speed is not an issue with the small production runs of the modern hand sewn book.
Discolouration could be of great concern to a newly sewn book that uses a coloured thread, that will pick up dirt with handling or sitting in a dusty environment. Wax could also transfer to the paper face and may interfere with water-based art media or discolour the page.
One can find many pre-waxed linen threads, but often the wax is far too heavy and is of unknown type. These threads are designed to be used with leatherwork where the wax aid the thread being pulled through the material and not for bookbinding. It is best to lightly add wax to an un-waxed thread by running it across a solid piece of wax.
Thread has a natural twist to it and running it against a material like paper will induce a curl to the thread. Wax helps reduce this by lubricating the contact. With careful attention when using un-waxed threads, these tangles can be eliminated by occasionally letting the needle naturally unwind.
Some waxes have an acidic component to them (see chart below). Generally, you can’t measure the pH of a wax because by nature wax doesn’t dissolve in water. The pH scale is a ranking of the acidity in aqueous solution. The better measure is the Acid Number (AN) of a substance, which is a measure of the amount of potassium hydroxide (KOH) required to neutralize all the acids (both water soluble and insoluble) in a substance. Beeswax can have a range of AN based on the type of bee and the environment it lives in and there are always acidic elements. Microcrystaline wax is truly neutral and is probably the only one to use if you decide to wax.
Some say wax makes a tighter knot. Well, it is true that the additional lubrication allows you to pull a knot tighter, this lubrication also works in reverse allowing the knot to loosen easier. There really is no advantage.
Lubricates the thread for sewing speed.
Can reduce thread tangles.
Cons of using wax:
Attracts dirt which discolours the thread and/or page.
Some waxes are slightly acidic which may damage the paper.
Pre-waxed thread often has far too much wax.
Wax interferes with adhesion.
AN Comparison Table:
| Approximate Acid Number (AN) | |
| Microcrystaline Wax | neutral (<.1) |
| Beeswax | 18 |
| Carnauba Wax | 78 |
| Olive Oil | 190 |