Too bad this sword by WKC wasnt in better shape. I'm not sure if the fittings are made of aluminum or some zinc alloy material. I think the corrosion is beyond repair. Which is a shame for a uncommon sword.

2nd Pix

How's the blade? This piece might not be beyond hope, can't really tell from the resolution of the pictures. Are you sure they're not patinaed?

The image is not quite close enough, but I think that the hilt is probably zinc not aluminum. Aluminum does not corrode in the traditional sense and what looks like whitish deposits might be from zinc and/or a lead extender that was used as the casting alloy for the hilt.

Once corrosion gets a start there is not much you can do but remove it and keep it away from moisture. The corrosion can become hydrated (moisture within its chemical structure) and may act as a reservoir for moisture keeping it in contact with the base metal and perpetuating the corrosion - which is microscopic in nature and invisible to a casual inspection. And zinc and especially zinc/lead alloys by themselves are notorious for being corrosion prone. FP

The blade is in good shape. And the corrosion is severe. I suspect that Freds thoughts on the zinc alloy problems are true with this sword. Its kind of like a time bomb waiting to go off with the metal reaction.

I have always suspected that the aluminum hilted swords were more susceptible to oxidation and deterioration of the gilding than brass hilted swords, am I correct? if so, what if anything can be done to protect them? I have several that are especially nice, they have been packed away for 30 years and so far , so good, but I hope to hang them on the wall someday. Thanks? Joe S

Joe, Aluminum, especially anodized aluminum, is fairly stable. A dye is added to color it and while it might fade a little that’s about it at least in our lifetimes. If there is a break in the anodized skin for any reason it will heal but it will be aluminum colored. That is the real advantage of brass hilts over other materials because if the gold electroplating is worn off it’s still colored more or less the same, and there is good bonding between the two metals.

Gold itself is relatively imperious to almost everything. And gold can be used to electroplate aluminum but it’s more problematic than brass. Because aluminum “heals” very rapidly (it forms a protective oxide layer) the Germans had to first “zincate” it by special preparation and a layer of zinc over the aluminum. The zinc layer could then easily be electroplated. Because the zinc used in the electroplating was probably a higher grade alloy I don’t think that it's as liable to be as self destructive as zinc/lead. The Germans recognized the problems with zinc and sometimes applied a lacquer/organic finish on top of the plating to try and prevent moisture from penetrating it.

I also would want to make sure and try and protect a plated aluminum hilt from any moisture or anything that would necessitate periodic cleaning because it is more fragile. In the long run the gold plating on an aluminum hilt will not be as durable as on a brass hilt. But with proper care* plated aluminum hilts should still last a long time if they are not already damaged or mistreated.

* Many variables: Good storage or mounting in a dry environment is a must. Minimal handling (etc.) If a hilt is in good condition with 100% lacquer I would leave it alone. No lacquer, possibly a light coat of wax applied very carefully. I think a lot depends on the individual sword and what the maker originally did (or don’t do) to try and maintain some continuity with what was done 60 plus years ago. Regards, FP

I did not realize the alum hilts were anodized. In my collection I have alum hilts that have a very bright "hard" finish, like a plated finish, and others have a softer appearance. Were all alum hilts anodized or were some plated? A friend of mine has an alum hilted Justice saber that has been hanging on his wall for many years. A lot of the gold finish has dissappeared as a result of corrosion. I know he takes good care of his collection, It appears the corrosion is the result of exposure to various elements in the air. Thanks! Joe S

Joe, With aluminum the Germans basically had two choices. Anodize or electroplate. Anodizing itself generally has a soft appearance because the light is diffused by the aluminum oxide layer (like that seen with the aluminum Luftwaffe dagger/sword gold colored ‘sun wheel’ on the pommels).

Electroplating itself is a whole separate issue. Because a bare metal surface is required for the plating to adhere to the aluminum it had to be specially prepared for the zincating. And then they could use different plating alloys and intermediate plating to try and minimize the amount of actual gold needed (true for all base materials).

Especially thin electroplating is permeable. And once corrosion has a secure foothold (with zinc/zinc alloy being a weak link) it just keeps on corroding unless aggressive action is taken to remove it. Which for many of these items is a case where the cure is more damaging immediately than the gradual falling away of the original finish.

PS: If you think that corrosion is a problem for sword collectors - it is the reason (IMO) so many especially high end daggers have had the crossguards replaced at some point in their careers. The reason being that in addition to the environment the wood grips are to some extent acidic. And nickel silver replacements over the long term are less affected by the various environmental factors than the nickel plated type of crossguards unless mounting/storage conditions are very closely controlled. Once corrosion is started very unfortunately it’s usually only a matter of time - with some metals being more prone to problems than others. Regards, FP

In the toy train hobby, collectors of the German Marklin locomtives and cars from the 1948-55 call this "Zinc Pest".

See below for an example. A DRG Class 01 fast passenger locomotive is in front. The tender is completely white with zinc pest. As far as I have ever been able to find out there is no cure and no really effective way to stop the rot.

Dave

You will see this same phenomenun in antique pewter which is a combination of tin and antimony. When "pewter sickness" sets in the metal turns almost to a powder and badly affected pieces will literally crumble in your hands.
Jim

Now I am more confused than before. I have seen alum sword hilts that have suffered serious deterioration. Can we conclude that alum hilts are relatively stable if not damaged, but that once corrosion sets in, its almost impossible to stop? That is what I am getting from the various posts. Joe S

Joe:
I suspect Fred,or perhaps some other forum member, will be able to give you a more technical explanation here but it's been my observation that just about any common metel iron,steel,pewter,zinc etc. if allowed to corrode under favorable conditions such as high humidity or a lot of salt in the atmosphere for example will eventually reach the point where it will just disintegrate much as wood will rot over time.
Jim

Joe:
First, I think that we have to make a distinction between anodized aluminum and plated aluminum. Aluminum by itself is reasonably stable, but as Jim says it like many metals is not impervious to corrosion. Some aircraft have corrosion induced structural failures, so environment has a lot to do with it, but I honestly can’t remember when I last saw an anodized aluminum Luftwaffe sword that had corrosion issues. The operative word here being “anodized” which is a protective artificially induced heavy duty layer of aluminum oxide.

Plated aluminum is another matter and both aluminum and zinc are reactive metals. Aluminum burns and zinc is used as a sacrificial metal (with copper and especially gold being towards the other end of the scale). To provide a suitable base for plating aluminum has to first be etched mechanically and/or chemically to give the plating something to anchor to. This creates a lot of little hills and valleys in the object which can become microscopic corrosion cells if the outer surface is injured and the interior is exposed to moisture. And moisture is permitted to come into contact with something like zinc and there is an electron flow between the two dissimilar metal layers. And the corrosion byproducts become hydrated accelerating the destructive process. So your thought that “once corrosion sets in, it's almost impossible to stop” is probably correct unless it can somehow be removed completely.

Probably more than you (or anybody) wanted to know but put simply anodized aluminum hilts will probably be OK unless they are really abused. But plated aluminum (and especially zinc) hilts should be given extra care to protect the plating and they should be kept away from moisture in any form.
FP

PS: Nice trains!!!

As far as I have learned the turning of tin and it´s mixtures ("pot metal") -yes it is tin not zinc- to white and even to powder depends only on temperature. I do not remember exactly but I think to remember from 10-7 C the process slowly starts, also depending on time. Long time in a colder environment (the colder the faster) makes it visible and unreturnable. Perhaps moisture "helps" the process to become faster because moister = cool. What I have learned, it is the change from chemical socalled "alpha" to "beta" tin (or the other way round) and one of it ist a white powder consistence (somehow comparable with ice which turns to running water only due to temperature).
Nevertheless don´t let us forget that tin in former times has been an expensive metal which could be cast very well. So the using of tin and tin mixturs has nothing to do with low (cheap) quality. But naturally the above desribed effect has been known therefore the use of other materials until these materials had to be used mainly for war.

Thanks Fred, your post in NOT more than I want to know, it is exactly what I want to know. Very informative. Thank you very Much! Joe

Joe,
I Want To Thank You Very Much!! The question provided an opportunity to cover some of the basics about how some of these historical artifacts were created, what can go wrong, and how they can hopefully be preserved for future generations. And I even managed to hold myself in check every time I mentioned “anodizing” - almost

Wotan,
In American automative and other industries “pot metal” generally refers to zinc die castings. What you are describing I think is the “Pewter Disease” that Jim mentioned. I have doubts where tin figures into the equation as regards period German nonferrous hilt/fitting casting metals. Greater Germany (including both Austria and Czechoslovakia) had over 9% of the world supply of zinc. And over 5% of the world supply of lead. But Germany only had 1/10 of 1 % of the world's supply of tin which was 13 times less than the amount of copper that they had.

Besides the scarcity of tin one of the other problems that I have with the idea of tin hilts is this: Pewter Disease/Tin Disease/Whatever - At 56° F (13.3° C) tin begins the process of decomposing and the crystal structure starts to go from a white tin (silvery/ductile) to the brittle gray tin. And there is ultimately a 25% plus increase in volume which is what causes the metal to turn to powder. And pewter disease is not reversible. The process is fairly gradual down to about 32° F (0° C). Where it gets really interesting is that at about -31° F (-35° C) tin decomposes virtually spontaneously. My point being that if the hilts were made of tin instead of zinc or zinc/lead we should be seeing a lot more hilts that don’t just have plating problems. But hilts that have already disintegrated or are in the process of turning into powder.
FP

Typo correction: “In American automotive and other industries”

Frogprince, thank you very much for an again deep inside in technology and metalurgic problems. It sounds locical what you write. I do not know much about this thing beside what I have heard. The only thing that let me believe that also tin alloy has been used is this certain white powder and also the so concrete decribed increase in volume which I sometimes (partial) could observe on several edegd weapons.

Wotan,
What metal does what under different circumstances can be and is confusing. For example commercial tin oxide is manufactured by passing ground up tin through a flame creating a white powder. Electroplating tin can also yield a white appearance. But tin/pewter-pest/disease results in the metal breaking down into a gray colored powder.

Zinc oxide is also white and is used commercially for a number of things - including the stuff you put on your nose to prevent sunburn. Naturally occurring zinc hydroxide is white and is simply zinc in combination with water. Likewise, unoxidized aluminum with water will also form a white hydroxide compound. My point being that white corrosion byproducts are not confined to just one metal and other factors have to be taken into account.
Regards, FP

Frogprinc, I totally believe and agree to what you have said. I as said I do not have any deeper knowledge on those metalurgic processes. And I am glad to hear and learn.