Date: Sat, 15 Aug 2009 11:42:53 -0500
Reply-To: Tom Hargrave <thargrav@HIWAAY.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Tom Hargrave <thargrav@HIWAAY.NET>
Subject: Re: Electronic Rustproofing?
In-Reply-To: <4a86c227.12025a0a.41bc.fffff511@mx.google.com>
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Corrosion occurs when you have metal surfaces with positive ions and
negative ions and those areas are bridged with a conductor (water or salt
water) Surface rust is caused by positively charged metal surfaces being
exposed to oxygen and it not the same as corrosion. Actually, surface rust
can build up a barrier that will help to prevent corrosion. Aluminum and
copper as well as quite a few other metals will do this as soon as they are
exposed to air, so does stainless steel. So will mild and high carbon steel
if given a chance - this the dark brown coating an items like carbon steel
knives, the brown coating (called browning) on old handguns & long guns and
on old steel antiques. Some of today's spray on "rust converters / stoppers"
chemically build a brown oxide layer and if applied right, work well.
The electronic Rustproofing devices work by keeping everything at a slight
negative charge and the theory is that with no positively charged metal
there will be no corrosion. I remember people trying to sell these in the
70s and even then those who were selling the units could prove they worked
"in theory". The problem comes from that fact that we all already have one
of these devices installed in every one of our cars!!!
Let me explain.....
Years ago car manufacturers noticed that car bodies with a positive ground
electrical system would corrode much faster than car bodies with a negative
ground electrical system. This is why all cars manufactured today have a
negative ground electrical system. All of the positive ions gather on the
positive side of the electrical system (the hot side) and all of the
negative ions gather on the negative side of the electrical system (the
ground side which also happens to be the car body). This is also why the
surface of your copper wires turn dark so fast and why only the positive
terminal of your battery corrodes!
BTW, boats take a much more aggressive approach. They bond all of the metal
parts together with copper wire then they run a wire to a sacrificial anode,
usually zinc, below the water line. This guarantees that the anode has
positive ions & everything else has negative ions, causing the anode to
corrode away instead of the other metal parts.
We could do the same thing with our cars but I don't think you want to be
standing waste high in water. But VW and the other car companies did the
next best thing. They started building cars in the 80s with steel panels
coated with a sacrificial anode - it's called zinc plating. The problem is -
steel is different than any other metal alloy. Steel has localized regions
of positive and negative charged ions and body corrosion starts once the
anode (the zinc plating) has been used up, even in a small area.
And there are other issues with car bodies. Welding and folding plated steel
damages the zinc coating. Plus, once seam areas get wet they tend to stay
wet. This is why corrosion usually starts in seams - the zinc coating was
damaged during manufacturing and / or was used up there first. The right
answer is to repair those areas then protect them with a good undercoating
that won't let oxygen (air) or moisture come in contact with the steel
surface. Undercoating seams that have started to rust will only slow things
down because you can't get the moisture out.
Thanks,
Tom Hargrave
Our Web Sites:
www.kegkits.com
http://www.kegkits.com/JABF/
www.stir-plate.com
www.andyshotsauce.com
256-656-1924
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf Of
Max Wellhouse
Sent: Saturday, August 15, 2009 9:12 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Electronic Rustproofing?
Well, the title says it all. I was on the Subie Outback web page and
saw this little gem. Apparently some dealers are selling electronic
rustproofing for your car now. Can't confirm what country this was
in, but a reply on the post was a guy from Austrailia fixin' to
become a dealer for such stuff. To say the least, she got a lot of
response saying it wouldn't work and the process was likened to the
electronic(magnetic) fuel conditioners for sale
So, I don't think I've seen this thread discussed on the Vanagon list
so far, so have at it boys and girls!! Would be great if it did work.
DM&FS
Link provided by the Aussie
http://www.couplertec.com.au/index.html