if you mean the exhaust pipes it depends on the car. older cars were usually made of steel. now they use stainless steel alot.
Most metal pipes thickness are 25 mm
They are the exhaust pipes, they take away the burnt fuel gasses.
Usually the pipes that the smoke comes out of at the back of the car. Or if it is a semi-truck, the pipes that the smoke comes out of are at the top of the place where the driver sits.
Its under the left side if you are looking at the car from the front. Get under the car and its kind of hiden near the exhaust pipes.
Lead
Steel
Car bumpers, Pot's, plastic barrels, metal pipes, brooms, cards, stop sign, car rims, and many other recycled objects.
The low pressure tap or fitting is located on the compressor underneath the car drivers side. It is the larger of the 2 metal pipes.
People uses a lot of different metal, but most are made out of sheet metal.
Depends on the type of car. the average small car is under 1 ton
if it soaks into the metal, wouldn't it end up in a puddle under your car??
look underneath your car from muffler back and follow the exhaust pipes. Look for any loose/broken/rusted clamps that keep your exhaust pipes connected to the heat shield (metal strip surrounding exhaust pipes to prevent damage to car under body or anything underneath. It may be separated at a part so that when you rev your engine or at least turn it on the shield hits the pipe causing the vibration/noise. If not then look for anything else hanging or out of the ordinary or have someone else look at it.