electronic rust protection for cars - Page 3 - Electronic Circuits Projects Diagrams Free

rjvh · 13th August 2008, 02:24 AM

Quote:

Originally Posted by Hero999

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** · 13th August 2008, 09:42 AM

Quote:

Originally Posted by 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?

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 · 13th August 2008, 11:37 AM

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

Quote:

Originally Posted by 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.

BaCaRdi · 13th August 2008, 11:44 AM

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

Quote:

Originally Posted by Nigel Goodwin

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 · 13th August 2008, 01:33 PM

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 · 13th August 2008, 02:03 PM

Quote:

Originally Posted by 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.

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 · 13th August 2008, 02:19 PM

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 · 13th August 2008, 04:06 PM

Quote:

Originally Posted by 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).

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** · 13th August 2008, 04:15 PM

Quote:

Originally Posted by jpanhalt

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 · 13th August 2008, 04:48 PM

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.

arrie · 13th August 2008, 05:05 PM

Yip,

I seem to have had it right. Motorbikes eat alu for their frames.
But it also seems cro-mo for cycles have come and gone, alu-alloy and carbon fibres are preferred.

CroMo composition:
http://en.wikipedia.org/wiki/Chromoly

There, your rust problem is solved, cut out everything steel (use a grinder) in your car and replace it with a combination of alu, alu-alloy, SS, cromo and carbon firbe.

Good luck.

jpanhalt · 13th August 2008, 06:26 PM

Quote:

Originally Posted by Nigel Goodwin

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.

My information came from an aircraft builders' site and is presumably specific for 4130. It may be a regulatory thing and may vary with alloy of the brazing rod, but I felt it was worth noting. Also, remember silver/hard soldering and brazing are slightly different processes. Some bikes etc. may actually be silver soldered.

There are some relatively new silver solders that are user friendly and quite strong. I was sent a sample by Lucas-Milhaupt last year (Easy-Flo3 #503) and tested it on some 300 series stainless tubing. It was almost as easy as soldering with 63/37 lead solder on clean copper. It gave the best wetting and flow I have seen on stainless. The joints could not be broken and remained malleable.

John

dknguyen · 13th August 2008, 06:59 PM

Quote:

Originally Posted by 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

It's used for pipes, tanks, and building structures I believe.

**Nigel Goodwin** · 13th August 2008, 08:15 PM

Quote:

Originally Posted by arrie

Nigel, but surely motorbike frames are not made from the same material as cycle frames.

Back in my day they both used plain steel tubing (with the exception of the Aerial Arrow - which didn't use tubing at all). Motorbike tubing was a bit thicker and fatter walled, that was all.

Modern bikes, and motorbikes, are made of all sorts of weird and wonderful materials.

A neighbour of mine works at a large local motorbike sales and service place, I was talking to him the other year, and they had a recall on a particular expensive model (I think it 'might' have been a Moto Guzzi - something fairly exotic anyway). What needed replacing was the rear swinging arm, which was a single arm rather than a twin, with the suspension right at the front, so it had to be VERY sturdy. Apparently it was a real rotten job to do, but the mechanics didn't mind, because it was made from Titanium, and they got £80 as scrap metal for each one!

BaCaRdi · 14th August 2008, 03:53 AM

AMEN, Braising or a TIG weld has much better penetration then say MIG/ARC resistance wielding etc.

-BaC

Quote:

Originally Posted by Nigel Goodwin

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.

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13th August 2008, 01:33 PM	#35
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.

13th August 2008, 02:19 PM	#37
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).

13th August 2008, 04:48 PM	#40
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.

13th August 2008, 05:05 PM	#41
arrie	Yip, I seem to have had it right. Motorbikes eat alu for their frames. But it also seems cro-mo for cycles have come and gone, alu-alloy and carbon fibres are preferred. CroMo composition: http://en.wikipedia.org/wiki/Chromoly There, your rust problem is solved, cut out everything steel (use a grinder) in your car and replace it with a combination of alu, alu-alloy, SS, cromo and carbon firbe. Good luck.