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
The NETTING? NO PROBLEM!
The journal "modelist-Konstruktor" write for a long time, almost from the very origin; learned a lot of useful for yourself. In response to your appeal to be not only a reader, but the...
WILL BE IN THE HOUSE WARMER
Preparing for the winter days, you carefully insulated Windows, vents, entrance and balcony doors, but with the onset of cold weather felt still lack of heat... it is not necessary to...