Aluminum Body Panel Conductivity.

rcmiller32 wrote:
RoyB
The frame on the new Ford F150 is steel. Only the body is aluminum.

Even if the frame was aluminum it wouldn't be an issue as most commercial trucks have used aluminum frames for decades without any electrical issues.

Sport45 wrote:

v10superduty wrote:


Ford pickups have had aluminum hoods since 1997 ....

All Ford pickups or just the half-tons? I never stuck a magnet on the hood, but by '00 F-250 definitely had a rusty spot where a rock had chipped paint off the leading edge of the hood.

Just the F150.

Got me going back to college books and did a quickie search to refresh

Cadmium plated fasteners are preferred over SS fasteners for aluminum,
but many will use SS, which does NOT have the grades available like steel
fasteners


Aluminum has about 5 times the thermal conductivity over steel...dependent
on alloy

Aluminum has about half the electrical conductivity of copper (don't
ever remember any comparison to steel)...as steel is NOT considered
an electrical wiring conductor because it is NOT as flexible. Aluminum
can be made to have a higher electrical conductivity, but that then
makes it more dense and not as flexible

Aluminum is anodic (sacrificial) to the other metal toward cathodic (noble or inert)
The farther away, the more active (sacrificial, or electron flow) the
aluminum will be. Meaning the aluminum will rot away when electrically
connected to the cathodic metal. There is a voltage generated in
doing this and the higher the voltage...the more electrons are flowing
and therefore metal molecules moved from anodic metal to cathodic metal

"Electrically connected" meaning water and the dissolved minerals...like
salt or whatever is used to de-ice

A hood does NOT see the amounts of road salts as does anything 'down
there' does....and that is where the potential issue(s) will be

Of course the designers will or should have had materials classes
and here are some of the generalized info for those who wish to bone
up on that aspect of this topic:

Galvanic corrosion

Steel Aluminum Galvanic Corrosion


The real potential problems are the road salt build up and the body
shop that uses the wrong materials. Biggie is the wrong fasteners
and most will think SS will be the best...yes it is the best for NOT
corroding the fastener, but the aluminum will be sacrificial to the SS

Hi Guys I work at GM Flint Truck Asm. all 1500 Lt Duty GM trucks use the Aluminum hood, with coated hinges and bolts for corrosion. Rest of the body is steel.

You can't just say stainless steel. There are five different types of stainless, within those 5 are a myriad of different alloys with different properties. I am reasonably comfortable assuming Fords engineers know which fasteners they can mate with AL.

v10superduty wrote:


Ford pickups have had aluminum hoods since 1997 ....

All Ford pickups or just the half-tons? I never stuck a magnet on the hood, but by '00 F-250 definitely had a rusty spot where a rock had chipped paint off the leading edge of the hood.

You would think no auto maker ever used aluminum in making body parts following some of this chatter. It is not uncommon now.

I know I don't se many Land Rovers hear but they have had a full alloy body and steel chassis as long as I can remember and only ever proplem was the rusted out chassis. They are build in a plase on the other side of the world caled Great Britan.
Frank

If you check the wiring coming into your house from the electrical company it is almost for certain aluminum. Aluminum is cheaper wire than copper for a given amperage and works just as well if used as intended.

The problem with the fires was nothing to do with the aluminum, it was disreputable contractors saving a buck or so per outlet and using designed for copper receptacles with the aluminum wire. Of course it is against code, but it was commonly done and I guess they paid off the inspectors or whatever (I know on my street there are houses with original aluminum wiring and brass screw receptacles)

OK, aluminum is a better heat sink than steel. Transfers heat faster, nothing to do with electrical conductance.