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I Forge Iron

De-rusting technique


sdalcher

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I ran across a technique for removing heavy rust from steel and iron. It consists of filling a nonconductive container with water adding sodium carbonate (pool additive to raise PH) teaspoon per gallon of water. You then attach a battery charger (car variety) negative electrode to rusyed part and then attach positive electrode to a piece of scrap steel. Caution are to wear protective goggles, do not allow the + and - charged parts to touch, dont reach in the water while connected, etc and use in a well ventilated area as hydrodgen gas is a by product.

Supposedly this process will not harm the base metal, no matter how long left in process.

I have several old sets of tongs that I would like to treat. I picked ouy the rusyiest set and hooked them up. Witin 10 minutes I had bubbles forming. After a couple of hours there was already a noticeable difference, I can't wait to see what they look like in the morning.

Steve

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  • 1 year later...

1 litre of Molasses poured into 20 litres of water in a plastic tub is excellent for completely removing heavy pitted rust. It even gets into the nooks and cranys.
The rusty item needs to be completely submerged in the solution and it usually takes up to 3 months. The moment you remove it from the tub and give it a quick wash with the garden hose, it begins rusting. A light rub with a wire brush and a splash of CRC or WD40 usually does the trick. Molasses is available at most grain stores as it is used as an additive to charf for horses to eat. Usually costs about AU $2.60 / litre. Take your own container as they get it in bulk.
Cheers Chrispy. ps it stinks a bit but worth its weight in gold.

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  • 1 month later...
I ran across a technique for removing heavy rust from steel and iron. It consists of filling a nonconductive container with water adding sodium carbonate (pool additive to raise PH) teaspoon per gallon of water. You then attach a battery charger (car variety) negative electrode to rusyed part and then attach positive electrode to a piece of scrap steel. Caution are to wear protective goggles, do not allow the + and - charged parts to touch, dont reach in the water while connected, etc and use in a well ventilated area as hydrodgen gas is a by product.

Supposedly this process will not harm the base metal, no matter how long left in process.

I have several old sets of tongs that I would like to treat. I picked ouy the rusyiest set and hooked them up. Witin 10 minutes I had bubbles forming. After a couple of hours there was already a noticeable difference, I can't wait to see what they look like in the morning.

Steve


You can do the same thing with borax and a car battery charger. It will also put a layer of black oxide on the part to help keep it from rusting again.
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  • 4 months later...
  • 3 weeks later...

I had good results doing this with Arm&Hammer washing soda. If I understand what is going on, this is making an electrical field in the electrolyte solution. This means the rusty target has to be turned to face the plate to get all the rust off, or to get it off faster. And being less than possessed of common sense I tried to light the hydrogen bubbles coming off the tank, but nothing went off.

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Muratic Acid and water mix then nutralize with hot water/TSP cleaner or baking soda...Bob


I'm not sure what actually happens chemically between steel and muriatic acid but the metal seems to go rusty at the slightest hint of moisture afterwards. I have cleaned brick laying tools with it and I have to keep them covered in oil when not in use.
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  • 2 weeks later...

Ferric chloride can form with muriatic and steel.

This is why it is so prone to re-rusting.

red rust is iron with an oxidation state of +3, Fe2O3, we don't like this kind.
black rust is iron with an oxidation state of +2, Fe3O3, we like this kind very much.

Old wrought iron that can't rust is already rusted with black rust. A protective oxidation. much like anodized when talking about aluminum.

Make black rust, it wont happen automatically anymore because old iron had phosphorous in it because it was turned into steel using charcoal, the natural phosphorous remained in the finished metal and helped to form a hydride upon atmospheric oxidation.

Modern steel is carbon doped with carbon from carbonate minerals like limestone. this causes a flux to lift impurities from the iron, subsequently modern iron has little to know phosphorous.

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I have a 24 volt battery charger wonder how that would effect the de-rusting process...


I have used 2 12 volt chargers in series with my electrolysis tub to speed things up, so your 24v charger should work fine. Just watch the ammeter so you don't overload it.
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Ferric chloride can form with muriatic and steel.

This is why it is so prone to re-rusting.

red rust is iron with an oxidation state of +3, Fe2O3, we don't like this kind.
black rust is iron with an oxidation state of +2, Fe3O3, we like this kind very much.

Old wrought iron that can't rust is already rusted with black rust. A protective oxidation. much like anodized when talking about aluminum.

Make black rust, it wont happen automatically anymore because old iron had phosphorous in it because it was turned into steel using charcoal, the natural phosphorous remained in the finished metal and helped to form a hydride upon atmospheric oxidation.

Modern steel is carbon doped with carbon from carbonate minerals like limestone. this causes a flux to lift impurities from the iron, subsequently modern iron has little to know phosphorous.



thanks that is a good thing to know.
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For small pieces I just use that common household vinegar (white). No electric current, just soak the part in it. It will flake the rust off and even flake it out of deep pits!

And it also will dissolve the galvanized (zinc) coating off of wire and rivets. It leaves a slight white-ish layer on the surface that rubs right off.

Mikey

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I use sodium bisulfate disolved in water to remove scale. A friend of mine, Bill Stewart, gave me some. It works quickly and even quicker if your solution is hot. You can put your hands in it, but you should rinse your hands off because it is a salt. I can leave pieces over night without problems, but it doesn't really take that long. It is used in this area of the country to adjust the Ph in the soil and to wash vegetables to get rid of salmonella. No batteries needed and no problems with disposal.

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I use sodium bisulfate disolved in water to remove scale. A friend of mine, Bill Stewart, gave me some. It works quickly and even quicker if your solution is hot. You can put your hands in it, but you should rinse your hands off because it is a salt. I can leave pieces over night without problems, but it doesn't really take that long. It is used in this area of the country to adjust the Ph in the soil and to wash vegetables to get rid of salmonella. No batteries needed and no problems with disposal.


to get the sodium bisulfate descaler to be turbocharged, just add some hydrogen peroxide.
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  • 2 months later...

You don't need much current or amps. I use a modded computer power supply at 12v it works fine. With the small of a current and amps I can stick my hands in find. Just make sure you don't have any open cuts. :)

Edited by blindviper
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  • 4 years later...

I use sodium bisulfate disolved in water to remove scale. A friend of mine, Bill Stewart, gave me some. It works quickly and even quicker if your solution is hot. You can put your hands in it, but you should rinse your hands off because it is a salt. I can leave pieces over night without problems, but it doesn't really take that long. It is used in this area of the country to adjust the Ph in the soil and to wash vegetables to get rid of salmonella. No batteries needed and no problems with disposal.

What concentration do you use?  What is your rinse or neutralize procedure?

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  • 4 weeks later...

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