You may be wondering what this construction is used for.

When you work in the field of ultrasonics (in water), it is pretty common that you need to get rid of some air bubbles that adhere to some surfaces. This tool can flush them away with a jet of water.

I have already built several tools made of a syringe and a silicone tube for that task. Putting several turns of emerald wire around helps to direct the tube upwards, which is handy if you want to remove air bubbles from some transducer surfaces. I learned about that idea while at PTB, and my colleagues in Helsinki like them, too.

The refined version that you can see in the picture consists of a 10 ml syringe (luer slip), a piece of silicon tube 3 x 1 (inner diameter 3 mm, outer diameter 5 mm), and a 1 mm stainless steel wire. A slightly thinner wire (e.g., 0.8 mm) can make the following steps easier.

Round the wire’s end with sandpaper to reduce the risk of damaging the tube. Shape an eye at one end, slightly larger than the inner diameter of the tube but not too large that it will damage the tube. The eye should be bent approximately 90 degrees to get its center coaxial with the remaining wire.

The carefully prepared wire can now be pushed into the silicon tube using, for example, a small screwdriver. The eye will fixate on the wire inside the tube. The steel wire keeps the tube in shape and allows it to point in any direction.

Before use, check that nothing is damaged, that there are no sharp edges, and that the wire can not become loose.