Aimed at children just learning the skill and 'outdoorsy' types which tend to snag their laces.
I'm thinking of lace which consists of (or includes) an expanding foam or plastic material. The material thins when stretched to facilitate tying. When the ends of the lace are released, the material slowly 'relaxes' - returning to it's original diameter and self-locking the knot. Pulling on both laces stretches the material again so the knot can be undone.
Another approach might be to use a lace (sparsely?) coated with an abrasive substance to provide the locking mechanism. This might make the laces difficult to undo, however, and they would need to be kept out of the hands of the incarcerated. A variation on this theme would be to have the weave of the lace modified to give the lace a texture and provide the slip resistance that way. But we'd might still have problems undoing the knot.
FWIW, these enhancements need only apply to the portion of the lace that supports the knot. Yes, I considered a semi-adhesive coating, but I think this would just get covered with dirt and become useless.-- phoenix, Oct 18 2001 I was thinking mainly of children who are learning to tie their shoes - and frequently don't pull the knots tight enough. I added the outdoorsperson as an afterthought. You might say "So let the parent tie the shoes", but that defeats the purpose.-- phoenix, Oct 18 2001 I have to agree with Peter on this. Thick cloth laces like you often get on trainers or walking boots do stay together far better than the thin shiny laces you normally get on dress shoes. I guess you could make them even thicker, but foam or plastic tends to be slippier than cloth, and it would stick in the eyelets. I suspect that a very thick lace would be harder to get tight as well, because it would resist bending more.
You could make laces out of something like barbed wire or velcro with lots of sticky spikes, but it would then be impossible to pull them tight. And I don't think you can make it slip one way but not the other, because different parts of the lace will be pulled in different ways - not just the two halves of the lace; the two ends of the loop will be pulled in opposite directions. And there's the problem of undoing them.
Velcro. The 1/2Bakery's fastener of choice.-- pottedstu, Oct 18 2001 I wanted to use staples, but my wife won't let me.-- phoenix, Oct 18 2001 I have a pair of shoes with the left lace made of flat material (which rarely comes undone) and the right lace is made of square leather which never stays fastened, and causes me to trip up quite often. (maybe I should replace it with a flat one) I have seen spiral laces aimed at children which fasten OK but are difficult to undo and don't really encourage bow tying skills only lots of winding round each other. Velcro is great - until it gets full of fluff and other strange hairy things. Why have laces at all? Wouldn't zips or even press-studs be better and less hastle. Or maybe a series of pegs.-- sessa, Oct 18 2001 Well, -I- like the idea, even if nobody else does. I wear hiking boots and the laces are always slipping loose. Leather is a pain in the neck to tie and prone to stretching, and eventual breakage, causing you to belt yourself in the mouth and frighten the cats.
Phoenix's idea is similar to a type of dental floss I've seen, a sort of cloud of filaments that, when pulled, narrows to fit between teeth, then expands to scrub better. I think something like this could be adapted...-- StarChaser, Oct 18 2001 People used to use laces for clothes also, but that's gone the way of fishbone corsets and bustles. I have 2 pairs of slip-ons with elasticated front or side panels (one by Diesel, the other Merrell) - stylish and so easy to put on, tying laces just seems silly now.-- pottedstu, Oct 18 2001 The problem is that it doesn't come undone easily when you want it to, either.-- StarChaser, Oct 20 2001 random, halfbakery