Drain Pipes in 1/35

The easiest and cheapest material is drinking straws.  You can even use the bendy straws to replicate bent ends.  Use a small piece of lead foil around it as the hanger/attachment strap to hold it to the wall.  Once painted and weathered, they look great.

Ditto drinking straws... I also use them, split in half, for rain-gutters. I then use strips of aluminum foil tape for the hangers...

I used brass tubing, foil from a wine bottle, sculpture armature wire for the bends and some model railroad rivets to make these pipes. To get the right scale, go outside and measure the width of the downspouts on your house and the divide by 35 (for 1/35 scale), then you know how wide a brass/copper/plastic tube to buy.