Visit your local scrap yard and buy a piece of carbon steel pipe. Most of the pipe found in the yard will be carbon steel and easily welded. Cut the pipe into 3 or 4 inch lengths and bevel (37 degrees) both ends so you can just add another nipple to the pipe you started with.
You can cut the pipe in a saw or torch cut it to the proper lengths. You can hand bevel the nipples with a hand grinder. You get practice cutting, grinding, and welding.
Al