Electronic rust prevention
Electronic rust prevention
Author
Discussion

Shodan

Original Poster:

1,866 posts

236 months

Friday 12th September 2008
quotequote all
Hi Guys,

Given that Tiv's chassis' are famous for rusting, I was wondering if anybody had tried one of these

http://www.couplertec.com.au/

I used to have one on my 4wd (1976 FJ40 smile) in AUS (it got used hard and was always covered in mud) and they do work really well. Easy to connect, unless they have become more advanced. Could be a much better solution than waxoil, tar, paint etc

Thoughts?

rsstman

1,918 posts

217 months

Friday 12th September 2008
quotequote all
looks interesting but they dont say how it works. passing some sort of current through the car? if it works why has it never caught on over here?

Mattt

16,664 posts

248 months

Friday 12th September 2008
quotequote all
I assume it's similar to ICCP systems, whereby the potential of the steel is lowered to a point whereby rust does not occur (read up on Porbaix diagrams if you want to know more).

Works on large structures, could work on car if set up correctly I suppose.

Buffoon

881 posts

234 months

Friday 12th September 2008
quotequote all
Mattt said:
I assume it's similar to ICCP systems, whereby the potential of the steel is lowered to a point whereby rust does not occur (read up on Porbaix diagrams if you want to know more).

Works on large structures, could work on car if set up correctly I suppose.
Tell me more. Thought said diagrams were for liquid solutions.

Love to think it works though, but I do wonder if this is like waving magnets or crystals over the cars psychic lociconfused

Mr.Chips

1,249 posts

244 months

Friday 12th September 2008
quotequote all
Hi Guys, some of these protection systems use a lump of magnesium (or other reactive metal) to act as a "sacrificial" electrode, so it will corrode instead of the steel in the chassis. Quite often used on narrowboats! They are a good system provided, there is a good electrical contact throughout the entire chassis.

Shodan

Original Poster:

1,866 posts

236 months

Friday 12th September 2008
quotequote all
I thought it was a little "snake-oil" like as well but my old FJ40 was in so much mud and water and never rusted. Anybody who knows FJ40's knows that they literally disolve, so I was impressed. This stuff is basically standard issue in the 4wd scene in AUS, I wonder if 4wd owners use it here?

Mattt

16,664 posts

248 months

Friday 12th September 2008
quotequote all
Mr.Chips said:
Hi Guys, some of these protection systems use a lump of magnesium (or other reactive metal) to act as a "sacrificial" electrode, so it will corrode instead of the steel in the chassis. Quite often used on narrowboats! They are a good system provided, there is a good electrical contact throughout the entire chassis.
I've seen the sacrificial anode system too - zinc discs in my case - pretty good, but not as good as ICCP (impressed current cathodic protection I think it stands for).

Mattt

16,664 posts

248 months

Friday 12th September 2008
quotequote all
Buffoon said:
Mattt said:
I assume it's similar to ICCP systems, whereby the potential of the steel is lowered to a point whereby rust does not occur (read up on Porbaix diagrams if you want to know more).

Works on large structures, could work on car if set up correctly I suppose.
Tell me more. Thought said diagrams were for liquid solutions.

Love to think it works though, but I do wonder if this is like waving magnets or crystals over the cars psychic lociconfused
The diagrams work for reinforcement placed within concrete - but I'm no chemist, so can't really explain any more.

GreenV8S

31,021 posts

314 months

Friday 12th September 2008
quotequote all
I would have thought they would only protect metal that was 'connected' to the anode by electrolyte. So fine if you're immersed in seawater, not so fine in fresh air. This is why people go to all the trouble of galvanising things. You can protect over the scale of millimeters (so scratched galvanised steel won't rust) but not over longer distances unless the thing is immersed.

Shodan

Original Poster:

1,866 posts

236 months

Friday 12th September 2008
quotequote all
GreenV8S said:
I would have thought they would only protect metal that was 'connected' to the anode by electrolyte. So fine if you're immersed in seawater, not so fine in fresh air. This is why people go to all the trouble of galvanising things. You can protect over the scale of millimeters (so scratched galvanised steel won't rust) but not over longer distances unless the thing is immersed.
Not sure what you mean here, I was talking about bolting it directly onto the chassis of the Tiv. This site has a good description of how it works:

http://www.rustguardian.co.uk/how-it-works.html


Buffoon

881 posts

234 months

Friday 12th September 2008
quotequote all
GreenV8S said:
I would have thought they would only protect metal that was 'connected' to the anode by electrolyte. So fine if you're immersed in seawater, not so fine in fresh air. This is why people go to all the trouble of galvanising things. You can protect over the scale of millimeters (so scratched galvanised steel won't rust) but not over longer distances unless the thing is immersed.
This is what I thought. Great for off-roaders maybe but remains to be seen if any good for average runaround. Plus corrosion and oxidation (rust) are not intrinically linked. Vehicles caked in mud can be subject to acid / alkali corrosion, but may not be subjected to oxidation dependant on the compound, as it will be starved of oxygen. (yes i know oxygen is corrosive in it's own right). System I belive is aimed at restoring a PH balance, so car will still rust.

I wonder though if it will help with unseen corrosion inside the tubes (where wet)?

Prices anyone?

GreenV8S

31,021 posts

314 months

Friday 12th September 2008
quotequote all
Shodan said:
GreenV8S said:
I would have thought they would only protect metal that was 'connected' to the anode by electrolyte. So fine if you're immersed in seawater, not so fine in fresh air. This is why people go to all the trouble of galvanising things. You can protect over the scale of millimeters (so scratched galvanised steel won't rust) but not over longer distances unless the thing is immersed.
Not sure what you mean here, I was talking about bolting it directly onto the chassis of the Tiv. This site has a good description of how it works:
If you look up the term 'sacrificial anode' and then re-read their description, you may find my comments make more sense.

Shodan

Original Poster:

1,866 posts

236 months

Friday 12th September 2008
quotequote all
GreenV8S said:
Shodan said:
GreenV8S said:
I would have thought they would only protect metal that was 'connected' to the anode by electrolyte. So fine if you're immersed in seawater, not so fine in fresh air. This is why people go to all the trouble of galvanising things. You can protect over the scale of millimeters (so scratched galvanised steel won't rust) but not over longer distances unless the thing is immersed.
Not sure what you mean here, I was talking about bolting it directly onto the chassis of the Tiv. This site has a good description of how it works:
If you look up the term 'sacrificial anode' and then re-read their description, you may find my comments make more sense.
OK, I searched and read. Looks like a completely different system of achieving this to TBH. I am not talking about using the inherrent states of two different types of metals, the way I am talking about actually puts a mild current through the metal to stop it oxidising. Rust happens when metal is exposed to water and air, electrons pass from the metal to the water and air causing oxidation. If there is a mild current flowing through the metal, these free electrons pass into the water and air leaving the metal untouched

Buffoon

881 posts

234 months

Friday 12th September 2008
quotequote all
Well I too have had a read up. Still think it will be useless, though I can see where they are coming from. TVR do not present a nice capacitive plate thanks to GRP panels, but that aside their claims of protecting the paintwork are bizarre. I can't belive the paintwork will benefit from stuffing it full of electrons. Surely pigment bleaching from the Sun cannot be stopped in this manner?

Anyway, my head is hurting. Need to return to counting the ceiling tiles before home time.

GreenV8S

31,021 posts

314 months

Friday 12th September 2008
quotequote all
Shodan said:
OK, I searched and read. Looks like a completely different system of achieving this to TBH. I am not talking about using the inherrent states of two different types of metals, the way I am talking about actually puts a mild current through the metal to stop it oxidising. Rust happens when metal is exposed to water and air, electrons pass from the metal to the water and air causing oxidation. If there is a mild current flowing through the metal, these free electrons pass into the water and air leaving the metal untouched
It's the same principle. You can do it either by connecting a more reactive (higher electrovalent potential) metal such as Zinc versus steel, or by connecting to a voltage source. Either way, it encourages the anode to corrode instead of the material you are trying to protect.

wedgeinald

1,314 posts

220 months

Friday 12th September 2008
quotequote all
Is this the same reason/principal behind modren cars having a zinc "paint" or galvanised layer?

GreenV8S

31,021 posts

314 months

Friday 12th September 2008
quotequote all
wedgeinald said:
Is this the same reason/principal behind modren cars having a zinc "paint" or galvanised layer?
Yes.

Paxo1

147 posts

304 months

Friday 12th September 2008
quotequote all
this is really old technology that has been used in offshore structures etc for years. if its immersed in water etc it works a treat...in a classic car forget it it doesnt work...i remember this being discussed in the classic car mags etc in the 80's....save your money for waxoyl or even better.....a good coat of paint