My nine year old, Josh, went sailing this morning at the local lake. It was sunny and I suggested he wear his sunglasses. The inevitable happened, and during a planned capsize drill the sunglasses went off his head and into the drink, to be lost forever.

When he came home we decided we should make an adjustable Paracord sunglasses strap to keep them on his head when sailing in the future, using my sunglasses as a test-bed.

Other instructables were a bit clunky (no offence) and relied on bulky knots over the end of the glasses arms.

We wanted something more professional looking and streamlined, and I hope you will agree with us that we think we have achieved that. Read on to find out how.....

Step 1: Gather the Materials

We decided to use some red paracord, my sunnies, an adjustable paracord buckle, some lettered beads to personalise the glasses with my initials and some heat shrink sleeping to fix the ends of the paracord to the arm of the glasses, preventing the need for knots.

So you need:

Some sunglasses

A suitable length of paracord (see next step)

A lighter or other naked flame for melting the end of the cord

Some paracord beads with the letters or initials or letters of your choice

An adjustable paracord buckle (of the type with two holes with a spring clamp)

Some heat-shrink tubing (pictured)

Some way of heating the tubing to shrink it. I used an electric paint stripping gun, but you can use a naked flame,

You may not be familiar with heat shrink tubing. It is commonly used in electronics to insulate soldered joints. Essentially it is a rubber sized tube (varying diameters are available) which, when heated shrinks to fit what it is covering very tightly. It can be brought online or in electronics stores. Mine came from the German supermarket chain, Lidl's, in a variety of sizes packaged in a neat box.

Step 2: Prepare the Cord

First, put the glasses on your face and take a length of paracord. Place one end just behind one ear, then take the paracord around the back of the head, with some slack to just behind the other ear. DO NOT cut it at this stage but attach it temporarily to the arms with some sticky tape or similar.

Then make sure that you can comfortably pull your glasses forward and let them drop around your neck to hang freely, but not too low!

When satisfied, cut the cord and melt both ends using a lighter to prevent fraying. Be very careful and when it has begun to melt, wait a second or two, then wet your fingers in a cup of water and carefully smooth the ends so that the melted end is the same diameter as the main body of the cord, not bulbous. If left bulbous you will find it difficult to push through the beads or buckle. It can burn your skin as the nylon in the paracord gets very hot and holds the heat, so be careful and let it cool a little and wet your fingers. Touch lightly and momentarily to start with. You have been warned!

I then threaded the two beads with my initials half way down the cord, before putting each end through one of the two holes of the adjustable clip shown.

Step 3: Prepare Everything for Fitment

Choose a piece of heat shrink sleeping which can slip over your sunglasses arms, with a piece of paracord inside and slide the tubing, with the cord inside over the arms.

Remember to ensure that the paracord is on the OUTSIDE of the arm so it doesn't press against your head uncomfortably when you are wearing them.

In my case I chose a piece of tubing which was a snug fit with the paracord inside.

Then, remember to hold the tubing in place on the arm whilst pulling back the paracord a bit. You are aiming to have the paracord finish about five millimetres from the end of the tube.

See the pictures for detail. The second picture shows the end of the paracord. From this position, holding the tubing in place, pull back the cord to,within 5mm from the front end. This will ensure the end is hidden but most of the tubing is still trapping the cord.

Step 4: Heat the Tubing

This part needs care. Especially as my sunglasses were plastic.

Heat shrink tubing shrinks when heated to a tight fit. Obvious really!

I used an electric paint stripping gun to shrink my tubing, being careful to do it gently, but you can, carefully, use a naked flame.

Pay particular attention to heating the tubing equally all over and also at the lens end to ensure the 5mm overlap you left shrinks neatly down over the cord end.

Be careful not to melt your glasses!

Step 5: Enjoy

To use, pull back the buckle as far away from the glasses as you need to in order to put them over your head.

You can then let them hang around your chest until needed.

When needed, for example, sailing, running, or some other sport, place the glasses over your eyes, hold the beads with your initials on with one hand and then grasp the buckle with the other. Then slide the buckle to the back of your head snugly to keep them in place.

After years of sailing (and capsizing) I never lost my glasses using a device like this. The difference here is, I made it myself!

Have fun and enjoy.