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**SwordFish** · 03-02-2008, 06:35 PM

Rick,
I'm thinking about it an trying to picture what it'd look like. It sounds like the rust is on the sever side, if it's flaking in pieces. It also sounds like it's more than just surface rust. I really don't know that you're going to be able to save it. It sounds like deep rust from inside. If it were mere surface rust, a light sanding, or perhaps naval jelly would work. Even if you seal that track, it still may continue to degrade from the inside out. If you're going to attempt sealing it, perhaps a type of clear-coat spray paint?

It's a tough one when the rust reaches that point. Hopefully another member can provide you with some better ideas who has a bit more extensive experience with cases like yours.

**Stahlhelm** · 03-02-2008, 07:25 PM

The only way to stabilize rust without coating it with anything is to simply control the environment, so that the humidity stays below about 65%. Anything above that level is when rust is considered to be activated. In environments with humidity below that level rust is basically dead, and unable to progress any further, regardless of the damage it may have already done. Yes, rust needs that all important water to exist. Remove that, and it dies a sudden death.

However, since you live in an area where humidity is hard to control, your only choice is to take the item indoors, and store it in a room with humidity monitored by a hygrometer. These devices are inexpensive and can be bought almost anywhere these days. A dehumidifying fan in the room can also help to lower the humidity level, when it does get too high. I know that all may sound like a big headache to deal with, but short of that, I really can't think of anything else that will stabilize the rust. I do the same thing myself. It's just that the humidity level in my home never has so far exceeded rust-nourishing levels. However, the first important thing is to be constantly aware of the humidity levels, in general. From what I've learned, most collectors don't even seem to do that much.

As for coating it with anything, I'm not sure what might work or be practical on something which already has as much rust as your item has. Coating something that has "flaking" rust with anything that requires any type of rubbing or friction would obviously be a tricky job, to say the least. Anything you may coat it with would need to be something you could spray on to avoid the friction. I wonder how laquer might work in this case? Just an idea. Some may call me an idiot for even suggesting it, but I'm only trying to be helpful and throw out some new ideas for you. By all means, see what others have to say, before you do anything at all. Paul R. always has great advice with all this stuff, so wait and see what he has to say, for sure.

As for sanding and other types of artifact-altering things, I'm not sure. Although they normally just advise leaving it "as is", you obviously may have an exception. In your case, not doing something extreme may indeed mean the end of your tank track's life altogether, soon enough anyway.

Since I also collect meteorites (of course made mostly of iron), I have to deal with much the same thing as you, and I still haven't figured out the best thing to do. However, I'm at least comforted to know that no one else has yet either.

Although I've obviously reached no particular conclusion, I hope I've at least been of some help helping you think about it.

Let us know what you decide to do, and how it works for you. Who knows? Some of the rest of us may find ourselves with the same problem someday.

Chris

**Mr. Scratch** · 03-02-2008, 10:20 PM

Originally posted by Von Hoth View Post

I have a Panzer 3 tank track link that is a little rusty and beginning to flake in large pieces. How can I stablize/stop it from further flaking but not change the original/overall appearance? is there a clear sealant or some other treatment I can try? I'm sure it doesn't help being in my garage one block from the ocean in florida, but I don't have room to store/display it inside my house yet.

thanks for any ideas.

Rust can be stabilized by treatment with tannic acid (available online, I buy mine on eBay). Tannic acid turns rust into iron tannate, an inert substance akin to magnatite. This is how museums deal with corroded iron items, such as with the current recovery of items from The Queen Anne's Revenge. There are a number of treatment methods online to choose from.

I use a solution of about 8% powdered tannic acid mixed with alcohol. If it were my track link, I'd scrub it with a brass brush to remove flaking rust. Believe it or not, under all those flakes there will likely be a relatively intact hunk of steel; rust expands as it forms, and so the flakes are much thicker than the same material in the form of compacted solid steel. In other words, you'll probably find that it isn't as in bad a shape as you assume. Anyway, the flakes must be removed if you are going to preserve the steel. Be sure NOT to remove the light surface rust beneath the flakes, as you'll need that rust to react with the tannic acid.

Once the flakes are off, then immerse the link in a container full of tannic acid solution. Scrub it down with a stiff bristle brush (if the surface is just a pitted out mess, go ahead an LIGHLY apply the brass brush or 000-0000 steel wool). Really scrub the hell out of it, as this forces tannic acid into every microscopic nook and cranny. Once this is done, rinse, lather, repeat a few times. You might even want to let it sit in the solution over a few nights to ensure maximum penetration. Be sure to wear gloves wher your're doing this, as the tannic acid turns into a kind of ink, and will seriously stain your skin.

Once it is all done, the iron will turn into a (rather pleasing IMO) charcoal color, and it will be the exact form of the steel, without having to add an artificial protective coating. The iron tannate will also help protect the steel beneath from further corrosion.

If you choose this route, I'd be interested to see your results. Let me know if you need any further advice on the process.

**Stahlhelm** · 03-02-2008, 10:43 PM

Well, I'm really happy to see that someone has some better advice. I've certainly learned some good information about this Tannic Acid. Great news, for sure!

Chris

**Mr. Scratch** · 03-02-2008, 11:14 PM

Oh, one other thing I would recommend that people should do with ANY rusted-out relic.

Take a fine point white paint pen, and on the underside of the track (where it will not be displayed), write in tiny letters exactly what it is, and what battle it was from, or location it was found. For example:

"Tread from a Tiger I Tank, Kharkov"

2 reasons.

1. If you don't, then I can almost guarantee you the link will someday end up in a scrapheap or garbage dump. To the average joe cleaning out an estate of the stuff the relatives don't want, it will look exactly like a peice of rusted out junk, and unless there is something very obvious to draw someone's attention to it's true history, it will be treated as one.

2. Even if it does end up in the hands of someone who appreciates it, without the location listed it simply becomes an anonymous rusty example. Think of the difference between a coffee-can half full of Civil War bullets. Now consider the value of an equivelent number of bullets, but with each bullet organized neatly into a sectional case and labeled "Bull Run", Shiloh", "Gettysburg", etc. BIG difference, and it only takes a minuteof your time. Once the information is lost, it is gone forever.

**Stahlhelm** · 03-02-2008, 11:45 PM

More good information above! Thanks, Mr. Scratch!

Chris

**Paul R.** · 03-03-2008, 09:05 AM

Good information on the tannic acid. Remember to wear protective gear while working on you item. Also work slowly. You don't want to re-due it over. it's a lot of work to get it completed. Paul

**Stahlhelm** · 03-04-2008, 10:58 PM

Originally posted by Paul R. View Post

Good information on the tannic acid. Remember to wear protective gear while working on you item. Also work slowly. You don't want to re-due it over. it's a lot of work to get it completed. Paul

On that note, it could be good to also explain a little of the potential dangers of using tannic acid. By that, I mean, what are the potential dangers to humans, if it is not handled and used correctly. What can happen, if it gets on human skin? What are the dangers of fume inhalation, etc.? I sure wouldn't want anyone to be harmed trying to clean off some rust.

After all, necessary precautionary information is, I suppose, about as important as anything else.

Chris

**Mr. Scratch** · 03-05-2008, 12:04 AM

Originally posted by Stahlhelm View Post

On that note, it could be good to also explain a little of the potential dangers of using tannic acid. By that, I mean, what are the potential dangers to humans, if it is not handled and used correctly. What can happen, if it gets on human skin? What are the dangers of fume inhalation, etc.? I sure wouldn't want anyone to be harmed trying to clean off some rust.

After all, necessary precautionary information is, I suppose, about as important as anything else.

Chris

http://www.jtbaker.com/msds/englishhtml/t0065.htm

Tannic acid is a pretty weak acid, and it is produced naturally in much of the vegetable matter we eat, exp. nuts. I'd take some reasonable low-level precautions, (don't get it in your mouth or eyes, or take a bath in it) but otherwise it is probably much safer than 95% of the cleaning products you have under your sink.

Apparently it can cause irritation to the skin. I assume they mean in large quantities, as I've gotten small amounts on my skin and never noticed it any more than I would notice drops of water. Then again, I always wear gloves when working with it anyway, as when it reacts with iron or steel it forms a black ink (the same substance was used for thousands of years to make ferro-gallic ink), which will seriously stain your skin.

It is largely odorless, what little smell it produces is a faint earthy odor. Again, you're probably in more respiratory danger from using Windex.

Really, it is pretty safe. Just use common sense with it, as you would any household cleaning product.

BTW, there is a good examination of tannic acid treatment process' to be found here, though they seem to have omitted one step - The item should be free of all oils before treatment (a bath in mineral spirits is best, but I've found even soap and water can be suficcient):

http://nautarch.tamu.edu/class/anth605/File10b.htm

TANNIC ACID
The corrosion-resistant nature of tannate films on iron was investigated by Knowles and White (1958) and later by Pelikan (1966). In accelerated exposure tests, it was found that tannate films on iron were more corrosion-resistant and lasted twice as long as phosphate coatings. It is important that the right tannic acid be selected, as many are not effective. Argo (1981) provides a discussion of the requirements and benefits of tannic acid solutions. Tannic acid solutions (such as Baker reagent tannic acid, C76H52O46) with a pH of 2.5-3.0 provide good, weather-resistant tannate films. Solutions of hydrolysable tannins, such as extracts of chestnut, myroblans, or valonea, with a pH of 2 to 2.5, provide the most weather-resistant protection (Knowles and White 1958:16). If the tannic acid mixture has too high of a pH, phosphoric acid should be added to bring it down to a pH of 2.4. In most conservation laboratories, tannic acid solutions are a standard part of the conservation of all iron artifacts. Although a tannic acid coating is often the final step in iron conservation, it is recommended that an additional sealant, such as microcrystalline wax, be applied over the oxidized tannate film for maximum protection.

In the past, the Conservation Research Laboratory at Texas A&M University has used a 20 percent tannin solution (200 g tannin, 1 liter water, 150 ml. ethanol) on iron artifacts. Logan (1989) states that solutions of tannic acid stronger than 10 percent are much too concentrated and recommends that several coats of diluted 2-3 percent tannic acid (with the addition, if necessary, of sufficient concentrated phosphoric acid to achieve a pH of at least 2.4) be brushed on the object. She also cautions that different brands of tannic acid react differently and recommends BHD Chemical tannic acid as working consistently well. Recent treatments conducted by the Texas A&M Conservation Research Laboratory on iron artifacts recovered from a 17th-century French shipwreck have demonstrated that a 5 percent tannic acid solution permeates the corrosion layers of the artifacts better than a 10 percent solution. In general, a 2-10 percent solution of tannic acid is effective; the concentration of the solution should be determined by the ability of the solution to permeate the corrosion layers of the artifact to be treated.

Several coats of the tannic acid solution should be applied with a stiff brush to the surface of the artifact. A brushed-on film provides better protection than a dipped or sprayed application because the brushing ensures that the solution has access to the metal in areas of loose rust. Brush application also eliminates the polarization of cathodic areas by the formation of hydrogen (Pelikan 1966:112). Objects such as cannon balls have also been successfully treated by vacuum impregnating them with a tannin solution. The object is allowed to completely air oxidize between each application of the tannic acid; after the final application, the object should be allowed to dry for one to two days.

The tannin solution reacts with the iron or iron oxide to form a ferrous tannate, which oxidizes to a mechanically strong, compact, blue- to black-colored ferric tannate. In order to ensure a continuous tannate film, Knowles and White (1958) recommend that all iron oxide products be removed from the surface of the artifact, otherwise there is a possibility that corrosion may start at the junctures of the cathodic iron oxide and the tannate film. Good results can be achieved even if this recommendation is not followed; Pelikan (1966:110-111) found that tannin solutions react directly with the metal base and with the rust if the solution is sufficiently acidic ( pH 2 to 3). In addition to forming a corrosion-resistant film, tannin solutions can be used to impart an aesthetically pleasing black color to iron.

A phosphate film is formed on iron objects by impregnating them with a 20 percent solution of phosphoric acid (H3PO4). Impregnation under a vacuum is recommended in order to ensure complete penetration of the acid into all porous areas of the metal. The acid complexes with the iron to form an inert film of ferric phosphate film on the surface of the metal. Reese-Jones (1972) describes the above procedure and reports that porous cast-iron cannon balls from a 1588 Spanish Armada shipwreck were successfully treated by this method after the chlorides were removed by water diffusion. Similar results can be achieved on wrought iron or steel.

Data reported by Pelikan (1966:112-113) indicate that a mixture of phosphoric acid and tannin solution can be used on badly rusted iron to appreciably improve the corrosion resistance of a phosphate film. One hundred milliliters of 80-85 percent phosphoric acid solution is added to the 20 percent tannin solution, and several coats are brushed onto the artifact. This is followed by at least four coats of the standard 20 percent tannin solution. Following the treatment of an object with the phosphoric acid-tannin solution, a final sealant should be applied to seal off the tannate or phosphate film. This solution does not result in the rich, dense black coloration that Baker tannic acid does by itself.

Regardless of whether tannic or phosphoric acid is used, it is highly recommended that a sealant, such as microcrystalline wax, be applied over the film formed on the object, The wax will provide a vapor barrier, which the film does not, and will also contribute some strength to corrosion layers on the metal.

**Ammersee** · 03-09-2008, 10:54 AM

Here's another product to deal with rust. This is for rusted metal items which will be painted. (or re-painted) The product is called "Extend". It's kind of watery, and white colored like milk. You clean the loose rust off and then paint it with the Extend. It then turns black and acts like a primer. It stops the rust and you then just paint over it. It costs around $10 for a 5 or 6 ounce jar and you can get it at most hardware stores. I've used it a lot on all the rusted junk I have here on the farm and I really like it. Ammersee

**Simon H** · 03-13-2008, 06:17 AM

For items such as track links which are fairly solid I usually sand or shot blast them and then coat them in clear lacquer. If you don't fancy that then commercial rust remover from your local store will get most of the loose flash rust off. Labelling your finds is a must.

**Tim B.** · 03-13-2008, 03:40 PM

Originally posted by Ammersee View Post

Here's another product to deal with rust. This is for rusted metal items which will be painted. (or re-painted) The product is called "Extend". It's kind of watery, and white colored like milk. You clean the loose rust off and then paint it with the Extend. It then turns black and acts like a primer. It stops the rust and you then just paint over it. It costs around $10 for a 5 or 6 ounce jar and you can get it at most hardware stores. I've used it a lot on all the rusted junk I have here on the farm and I really like it. Ammersee

You can also find similar products in marine (boat) stores; works the same way and after a couple of coats is pretty much permanent, but it does turn the item a blackened color.
Tim

**CurtD** · 03-14-2008, 07:04 PM

Another simple, poor man's way to deal with rust on small items that are all metal, is to simply heat the item -- like in an oven or kiln. This has the effect of removing the moisture causing the rust which stops it from progressing.

This obviously won't work with helmets with leather liners, but it is great for certain items that may have rust deep in the item which may be impossible to reach with any kind rust killer liquid.

I am no expert on this, but how long and at what temperature you heat the item depends on the item. So further research is required.

I visitied the Titanic exhibition when it came through town a few months ago. It included "The Big Piece" which is an 18-ton chunk of the ship's iron hull. Part of its conservation was treatment with tannic acid. It doesn't look natural anymore due to a shiny coating of "microcrystalline wax" (probably a giant jar of Ren. Wax). But, ya gotta do what ya gotta do.

http://www.conservationsolution.com/...s_titanic.html

**Stahlhelm** · 03-16-2008, 11:01 AM

I also collect meteorites, which as most know, are composed of large amounts of iron. As for stabilizing rust on them, (as it relates to other items), I can also add that the issue has not been fully resolved in some cases. For example, many meteorites which have been buried in the ground for periods of time have absorbed moisture deep within their metallic structure. So, treating them with anything on the outside can only have limited results. What often happens in these cases is that the meteorite rusts from the inside out, eventually collapsing into a pile of iron oxide.

So, even though I'm talking about meteorites here, I'm sure you see the comparison to militaria, particularly if it has been buried in the earth for some time and/or in especially humid environments.

In the scenario above, one of the recommended procedures is, as CurtD mentioned, to heat the item in some sort of oven for a period of time, to hopefully evaporate the moisture within the iron, rather than just what's on the surface. This is just another idea to consider, when thinking about truly stabilizing rust. However, I will also caution anyone to think of everything about your rusted collectible, before ever placing it in an oven. Obviously, heat can do more harm than good to lots of things. So, here the old addage holds just as true with only a small twist--Baker Beware!!!

Hopefully this recipe adds more palatable food for thought on the menu of Rust Prevention...

Chris

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