electronic rust protection for cars

[jpanhalt]

Phosphate treatment of steel is a widely accepted method to provide rust protection. A common name for it is Parkerizing.

John

 

[Speakerguy]

Well hell, they've been Parkerizing gun finishes for years. Glock even Parkerizes their finishes after their supposedly magic Tenifer process.

 

[dknguyen]

Why use a battery when you could just buy a block of magnesium and put it into contact with the material as a sacrificial anode? Smaller, cheaper, lasts longer. I'm not even sure how batteries would work current needs to travel in a loop so it seems to me you would just be shorting the battery across the metal part.

EDIT: I see somebody mentioned capacitve coupling. I can see how that would work, and be better than just using a large resistor to limit current.

 

[arrie]

Would it not be easier to buy a plastic or carbon fibre bodied car?

Why new cars last better than old ones regarding rust is a very new technology called galvanized steel. Really.

 

[dknguyen]

Would it not be easier to buy a plastic or carbon fibre bodied car?

Why new cars last better than old ones regarding rust is a very new technology called galvanized steel. Really.

Definately not as cheap though

 

[arrie]

Funny enough.
I still cannot see why plastic body manufacturing should be so much more expensive than steel. Then we are not even starting with aluminium-alloys, very popular today by so-called luxury vehicle manufacturers.
Wonder why.

 

[Hero999]

Plastic isn't as strong as steel and neither is aluminium.

 

[jpanhalt]

Plastic isn't as strong as steel and neither is aluminium.

Not quite sure what you mean by strong. For example, by weight, a lot of composites and aluminum alloys are stronger than steel. The 7000 series aluminum alloys (e.g., 7075 and 7068) are casually referred to as stronger than mild steel by hardness and tensile strength.

John

 

[Hero999]

I'm not talking about by weight, I mean by volume. Plastic is a lot less dense than steel and so is aluminium. Also, the composites that can outperform steel are a hell of a lot more expensive.

If you thing that there's another material stronger than steel that's cheaper, then why aren't they already using it?

 

[jpanhalt]

I'm not talking about by weight, I mean by volume. Plastic is a lot less dense than steel and so is aluminium. Also, the composites that can outperform steel are a hell of a lot more expensive.

If you thing that there's another material stronger than steel that's cheaper, then why aren't they already using it?

You have now added another limiting condition, namely cost. But, that wasn't included in your original statement with regard to strength.

Also, by volume, the aluminum alloys I mentioned (and some others) are stronger and harder than mild steel. Carbon fiber, by volume has a lot greater tensile strength than steel and weighs less. In fact, it cannot be cut well by HSS.

The use of steel over composites and aluminum boils down simply to cost in many cases. Ease of fabrication is another issue, as many strong aluminum alloys are very difficult to weld.

John

 

[rjvh]

Plastic isn't as strong as steel and neither is aluminium.

But kevlar is fibers can be used in a woven pattern and reinforced with polyester for shape and smooth finishings

it's only that fabrication costs are higher than conventional methodes

partly because it requires a different production line and that is a huge investment

matterial is deerder but could be competative if the demand whas bigger so more would be manufactored

the clasic who was first chicken/egg story

Robert-Jan

 

[Nigel Goodwin]

I'm not talking about by weight, I mean by volume. Plastic is a lot less dense than steel and so is aluminium. Also, the composites that can outperform steel are a hell of a lot more expensive.

If you thing that there's another material stronger than steel that's cheaper, then why aren't they already using it?

They use steel because it's CHEAP and easy to use, pressing body panels out in seconds and simply spotwelding them together. There 'may' be cheaper materials, but they aren't as cheap to construct with.

As for strength, a fibreglass bodied car is probably stronger than a steel one - but again cost is the issue, you need a chassis to build the car on, and lots of labour to create the body, rather than simply stamping out and spotwelding.

 

[BaCaRdi]

Great Idea with the Sacrificial anode! I know I have seen this before, I just can't remember where or what industry it was. I remember replacement blocks of metal as they wore out...

EDIT: AHH I remember it was in the fish hobby, a carbon dioxide generator
-BaC

Why use a battery when you could just buy a block of magnesium and put it into contact with the material as a sacrificial anode? Smaller, cheaper, lasts longer. I'm not even sure how batteries would work current needs to travel in a loop so it seems to me you would just be shorting the battery across the metal part.

EDIT: I see somebody mentioned capacitve coupling. I can see how that would work, and be better than just using a large resistor to limit current.

 

[BaCaRdi]

Yes and metal is very forgiving to work with, this is why I love working with metal. If you screw up you can start over and try again! If you bend it wrong, bend it back, if you make a tear or hole, you wield it, if all else fails melt it and start over! You wonder why even artist use metal as media Try that with carbon fiber..hehe

-BaC

They use steel because it's CHEAP and easy to use, pressing body panels out in seconds and simply spotwelding them together. There 'may' be cheaper materials, but they aren't as cheap to construct with.

As for strength, a fibreglass bodied car is probably stronger than a steel one - but again cost is the issue, you need a chassis to build the car on, and lots of labour to create the body, rather than simply stamping out and spotwelding.

 

[arrie]

I agree, steel is a great medium. Enjoy working with it myself.

But, most cycles are made of some alu-alloy, or what about CroMo, who remembers that. Cycles made from is this is just about the same price as the equivalent steel ones.
Interesting. CroMo is much stronger and lighter than steel. I also think if used more, it will become cheaper. But I doubt CroMo will be suitable for body panels, but great for chassis and suspension components, nowadays manufacturers are switching to alu to limit unsprung weight, etc.
CroMo would be better option I think.

But for some funny and possibly political reason I'll be wrong again.

 

[jpanhalt]

I agree, steel is a great medium. Enjoy working with it myself.

But, most cycles are made of some alu-alloy, or what about CroMo, who remembers that. Cycles made from is this is just about the same price as the equivalent steel ones.

If by "CroMo" you mean chrom-moly (in American), that is just another alloy of steel. Most often it is 4130, which is used extensively in aircraft too.

It is a very strong alloy, but should be welded, not brazed for critical applications, unless one is specially trained. If you aren't careful in brazing, you can get intergranular cracking over time.

One advantage of aluminum and "plastics" over steel is the variety of adhesives that are available for them. Sure, adhesives can be used for steel, but surface prep and bonding are well defined and very strong for both composites and aluminum alloys. Some of the proprietary methods of bonding aluminum used in aircraft (see: Boeing) are extremely strong, and because of the large surface area available in sheet bonding, they are preferred to riveting in certain applications.

John

 

[arrie]

Yip, that's the one.

You seem to know a bit about the different materials.
I've only in the past worked with wood, mild steel and few forms of plastic, like PE(very basic things done here).

 

[jpanhalt]

Yip, that's the one.

You seem to know a bit about the different materials.
I've only in the past worked with wood, mild steel and few forms of plastic, like PE(very basic things done here).

One of the neat things about PE and related plastics is the ease with which they can be welded. As you know, adhesives are not particularly good for them because of their slippery nature. However, hot-air welding is easy and gives a great joint. The technique is a bit different than for steel. Rather than forming a puddle and adding filler, with plastic, you push the filler into the joint. Effectively, there is no puddle, just surface melting.

Try it, you'll like it. John

 

[Nigel Goodwin]

It is a very strong alloy, but should be welded, not brazed for critical applications, unless one is specially trained. If you aren't careful in brazing, you can get intergranular cracking over time.

Interesting to hear that, I presume it only applies to that alloy? - we were always told that motorbike frames (and push bikes) should be brazed, because the vibration pass through the brazing, whereas they stop at the welds and tend to crack the welds over time.

 

[arrie]

Nigel, but surely motorbike frames are not made from the same material as cycle frames.
Motorbikes uses an alu-alloy, isn't it. Or maybe just some.
I still remember the days when motorbike frames were mostly steel as well.
Then after that everyone seemed to have a fling with alu.