Thin-walled tube of soft metal when you try to bend often creased. To avoid this, they are usually pre-stuffed with sand.
With the same purpose, you can use another method: navit on the future site of bend copper or aluminum wire – turns will not allow the tube to wrinkle at the bend.
The same result can be achieved using a suitable inner diameter of the spring.
Recommend to read
GARLAND BURN ON COMMAND
This switch Christmas garlands periodically includes four groups of lamps. The switching frequency can be changed within wide limits by the variable resistor R5 (see diagram). ...
MAIN BATTLE TANK Leopard 2
After the termination of cooperation with the United States of works on creation of a promising tank MBT-70 in Germany, decided to design a tank of the 3rd generation of their own. By...