Phosphoric-acid-treated sheet steel for cars

[jcfdillon]

One blog I saw stated that a car's typical paint job weighs about 8 pounds. Another discussion stated an estimate of about 600 pounds. I am thinking of removing all the paint from my car as an "ecomod." Has anyone thought about this?

My car has sheet steel body panels, all painted. So, if I remove the paint and prepare any rusted areas, I would then treat the entire surface with phosphoric acid, leave it overnight, at a temperature above 50 degrees F., so that the phosphorization is complete. Then I would go back over it a second time with more phosphoric acid, to make sure all areas got adequate treatment. After this is dry, I would then brush off any crusting and inspect the surface, make sure it is not too reflective (to avoid causing reflection into other drivers' eyes).

My main issue about painted sheet steel is that it hides rust and is unnecessary as long as the surface of the steel is phosphorized. (This process creates a nonrusting form of steel on the surface.) The weight of the paint is really minor if it's only a few pounds as I would expect.

Feedback welcome on this. (Replacing with carbon fiber composite body panels would be ideal in my opinion, but I won't be able to do this for quite a while.)

I am also treating the underbody rust with phosphoric acid. This chemical is available in gallon containers and larger, online. (Have to use rubber gloves and protect all skin and eyes, because it will burn your skin after about a minute. It really hurts to get droplets in your eyes and of course is not safe for kids or pets either.) However, phosphoric acid is used in food manufacturing processes and is in some soda and other foods. The chemical I use is called "food grade" phosphoric acid.

[Joris]

I guess it's about 15 to 25 kg for a midsized car, so not worth the hassle of stripping the whole car of it's paint and then adding some rust protective layer. Unless you realy want to do this and spend a lot of hours.

What you could consider is removing the underbody sealing. This thick layer in the wheelarches and on the underside of your car is quite heavy. Another thing you could consider is drilling holes in the non supportive metal, or even small ones in the supportive metal. That way it would save you time and have more effect.

[redpoint5]

I like the look of the Delorean. Too bad more cars aren't stainless steel or aluminum.

I'm not sure your rust inhibiting method will provide adequate protection from the elements. It's not just rust to be concerned with, but tree sap, asphalt from newly paved roads, bugs, and impacts from small rocks.

Not only is that a lot of work for very little savings, but weight reduction is pointless in terms of fuel economy.

I'd start with lighter weight wheels, brakes, and rotors, then eliminate the battery.

[aerohead]

Originally Posted by jcfdillon

One blog I saw stated that a car's typical paint job weighs about 8 pounds. Another discussion stated an estimate of about 600 pounds. I am thinking of removing all the paint from my car as an "ecomod." Has anyone thought about this?

My car has sheet steel body panels, all painted. So, if I remove the paint and prepare any rusted areas, I would then treat the entire surface with phosphoric acid, leave it overnight, at a temperature above 50 degrees F., so that the phosphorization is complete. Then I would go back over it a second time with more phosphoric acid, to make sure all areas got adequate treatment. After this is dry, I would then brush off any crusting and inspect the surface, make sure it is not too reflective (to avoid causing reflection into other drivers' eyes).

My main issue about painted sheet steel is that it hides rust and is unnecessary as long as the surface of the steel is phosphorized. (This process creates a nonrusting form of steel on the surface.) The weight of the paint is really minor if it's only a few pounds as I would expect.

Feedback welcome on this. (Replacing with carbon fiber composite body panels would be ideal in my opinion, but I won't be able to do this for quite a while.)

I am also treating the underbody rust with phosphoric acid. This chemical is available in gallon containers and larger, online. (Have to use rubber gloves and protect all skin and eyes, because it will burn your skin after about a minute. It really hurts to get droplets in your eyes and of course is not safe for kids or pets either.) However, phosphoric acid is used in food manufacturing processes and is in some soda and other foods. The chemical I use is called "food grade" phosphoric acid.

The finish on your car is the most expensive part of your car.A phosphoric acid bath was the first process the body went through before priming,color,and clearcoat,all with oven time in between.
The weight of the finish is statistically off the radar screen with respect to overall mass.
If you were a drag racer you might acid dip your chassis,as this has been done since the 1960s.
For a daily driver,this sort of weight reduction could be lost in the signal-to-noise ratio as far as fuel economy goes.

[oldtamiyaphile]

I stripped a car to metal in preparation for paint. I then used acid rust converter to keep the metal from rusting. Since I didn't have a garage the car still got wet at times and after every rain it was covered in rust again.

Still all that sanding of bare metal must have saved some weight, just like RS Porsche use thinner gauge metal in their panels

Or you could just let it go for that rat rod look. Bare metal actually doesn't rust away that quickly on the exterior of a body.

[Occasionally6]

Originally Posted by oldtamiyaphile

Or you could just let it go for that rat rod look. Bare metal actually doesn't rust away that quickly on the exterior of a body.

But that patina of rust would be adding weight back in with the Oxygen in the iron oxide .

[cowmeat]

One blog I saw stated that a car's typical paint job weighs about 8 pounds. Another discussion stated an estimate of about 600 pounds. I am thinking of removing all the paint from my car as an "ecomod." Has anyone thought about this?

IMHO, your time would be better invested in any activity you can think of other than this. You're never gonna see an ROI on this project, unless you just enjoy driving a car that looks like it was parked in the carport of a house that burnt down

Weight loss, unless it's extreme, would need some pretty sophisticated equipment to even measure the miniscule gains.