Rust Protector Circuit, please Help!

Discussion in 'General Electronics Chat' started by Manfred Von Steinborn, May 1, 2011.

  1. Manfred Von Steinborn

    Thread Starter Active Member

    Feb 3, 2009
    38
    0
    I have a rust problem on my collector car.
    My fuel tanks shed off some internal rust and the crud clogs the pumps. I don't want to pull out the tanks (too much work), so instead I'd like to slow down the corrosion process. I'd like to build a cathodic protector circuit which impresses a direct current pulse to polarize the steel tank and sacrificial zinc anode.
    Something like sold on eBay under the name Diamond Kote ("no rust" in Chinese).

    Does anyone have a schematic diagram?
     
  2. monster_catfish

    Active Member

    Mar 17, 2011
    110
    107
    The introduction of electrical current into an enclosure that contains even a hint of gasoline fumes sounds potentially disastrous to me, if I understand your intention correctly.

    In your shoes I'd visit Pick-a-Part, or some similar junkyard, and acquire a newer tank to be fitted by someone familiar with the grave risks involved in completing that swap. That is my layman's opinion, for all it is worth. Safety first.
     
  3. marshallf3

    Well-Known Member

    Jul 26, 2010
    2,358
    201
    Naw, it's safe since there's no arc and gasoline won't burn in a tank, it needs at least a 10:1 air:fuel mixture to ignite. I've seen this process used, it's similar to what we do on boats to protect the aluminum pieces.
     
  4. monster_catfish

    Active Member

    Mar 17, 2011
    110
    107
    I stand corrected, Marshall, though the procedure does sound dicey to me.
     
  5. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    3,772
    931

    I suggest you become much more informed about this procedure. Sacrificial anodes do NOT require any electricity to function. They are simply more reactive than the metal you wish to protect and erode away in preference to the protected metal. Impressed current cathodic protection can use zinc or magnesium or even aluminum anodes, but doesn't need to necessarily. It functions by making an entire structure cathodic in reference to the environment.

    A car is insulated from ground by rubber, so the corrosion you see is being caused by currents BETWEEN different portions of your vehicle. Quite possibly your battery is involved in the process as well. Look over the entire electrical wiring of the vehicle-starting with the gas level 'sender' unit and see what shape the wire insulation is in. Cracked insulation on a current carrying wire and condensation of atmospheric moisture can combine to create the needed electric currents.
     
  6. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
    230
    your corrosion likely occured during extended periods of inactivity, combined with moisture ingress. Nothing will reverse that, and corrosion prevention, best obtained by keeping your fuel cap sealed, will not prevent exsisting corrosion from continuing to foul your system. Your best approach is to install a sump screen prior to the pump, and a good filter after the pump. If the integrety of your tank is in question, replace it.
     
  7. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Cathodic rust protection for cars is a SCAM because the car must be continuously under salt water for it to work.
     
  8. t06afre

    AAC Fanatic!

    May 11, 2009
    5,939
    1,222
    A "trick" I use on my garage princess is to keep the fueltank topped up as much as possible. This will prevent building of condensation and hence rust on the inside. Rust from the outside and in is another probelm....
     
  9. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    3,772
    931
    @ Audioguro

    That is an overly simplistic viewpoint. Saltwater is one of many thousands of electrolytes that can participate in this type of corrosion mechanism. ANY element that can become ionized in solution is capable of supporting galvanic corrosion, even concrete can become an electrolyte in certain instances. The prevalence of SCAMMERS in any commercial endeavor is to be expected as a direct correlation between the difficulty of understanding the physics involved and the desire of the public at large to find a solution to the problem.
    The fact that there are scams in any particular commercial products field of application DOES NOT render the basic underlying physical principles moot.
     
  10. Manfred Von Steinborn

    Thread Starter Active Member

    Feb 3, 2009
    38
    0
    Thank you for your opinions.
    Actually, it is a very interesting "forensic engineering" case.
    May be just additional grounding straps from the tanks to neg terminal of the battery would do the job?
    On my Allante, which has an aluminum deck lid and steel hinges, on the left side, hi grade steel bolts corroded severely. Right side bolts were in "brand new" condition. I was told that the battrey grounding point to the body (right side, behind the passenger seat), has such dramatic effect on galvanic corrosion.
    IMO, if tanks and the engine are not grounded to the same point, there is a difference in potentials between them and fuel acts as an electrolyte.
    Zinc anode does not need any electronic gizmo, I know that. However, to complete the circuit the zinc piece should be suspended in the gasoline on the wire inside of the tank. There may be a problem with zinc contaminating the fuel.
    The electronic zappers look actually the most promissing. As far as I understand the principle of operation, the "grounding " wire carries a negative charge.
    But, there is always a "but", that is why I'd like to see the diagram.
    B Regards
    MVS
     
    Last edited: May 2, 2011
  11. marshallf3

    Well-Known Member

    Jul 26, 2010
    2,358
    201
    The ones I've seen are sometimes used by car collectors that store old cars for extended periods of time. A positive is attached to the auto body frame and the negative to a ground rod driven deep into the ground through a hole in the garage floor. This is upposed to work in higher humidity environments.
     
  12. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348

    And the rubber tires do what?
     
  13. t06afre

    AAC Fanatic!

    May 11, 2009
    5,939
    1,222
    What I remember from the chemistry lessons in engineering school. Was that for cathodic protection method using current. The current need to be regulated to a quite narrow range. If not it may accelerate the corrosion.
     
  14. marshallf3

    Well-Known Member

    Jul 26, 2010
    2,358
    201
    Insulate the car from the floor. Concrete is actually somewhat conductive as it never completely dries, it always maintains a small level of moisture.

    I'm not sure but I may have messed up, the negative may be connected to the car and the positive to the ground rod?

    Anyhow it supposedly works, not 100% but a bit of help.
     
Loading...