Can Science help distinguish replica, metal-made collectables?

[zorgon]

Apologies for the long post.

I would like to present to fellow collectors, an experiment I undertook at our local university this week. The purpose was two-fold; 1) to establish a “proof-of-concept” for using SEM-EDX to adequately identify the elemental composition of a collectable, metal insignia and, 2) to use this same technique to try to determine that, if by looking at the elemental composition, one might be able to determine replica or “fake” items within the vast field of collectables. To demonstrate the later, I choose to look at one of my collecting interests, the CAF (Canadian Air Force) insignia circa 1920-1924. They are uncommon enough that one generally doesn’t come across a large selection so collectors may only see these in isolation at shows, dealer’s stores, online or auction houses and at times, it can be very difficult to know if an item is truly an authentic, original, period piece or not. As we all know, it’s getting harder as the fakes and fakers get better.

The Zeiss-EVO SEM-EDX (Scanning Electron Microscope with Energy Dispersive X-ray) is an instrument which, beyond incredible imaging capabilities, allows materials research and analysis which can provide quantitative*, elemental identification. In my case, I was primarily interested in the later for my insignia not the imaging capabilities so coating of the samples wasn’t required and the technique is non-destructive; i.e., you get your stuff back intact and unaltered! The scientist who ran this instrument during my session was very knowledgeable, helpful and pro-active with suggestions (thanks Nathan).
Over the last few years, I have picked up several examples of the enlisted, Type 2 (with motto) versions of CAF collars which have had an unexpected crown for the issue. Unusual in the sense that it has the larger void shape normally reserved for Officer’s more complex, multi-component badges. Enlisted versions have a small void in the crown and are basically two-piece; a CAF monogram fitted over a die stamped body and fastened in place by a pin through the center then riveted to the back of the badge. Could there have been errors during assembly, some variant that hadn’t been reported or were they modern replicas?
The first two images below illustrate an original collar on the left and the questionable copy on the right. I’ve highlighted a few differences to note between the two. The lack of detail on the reverse of the replica is a give-away – if you know what to expect. Four additional variations are shown, each with a slightly different finish but by using the SEM-EDX, they show a wide variety of elemental compositions. The top left example is very interesting as it is mainly an alloy of tin with some lead. The finish is from an aluminum powder coating or paint and there is a high percentage of Cd, Cadmium in the piece, a toxic compound often found in off-shore costume jewelry. The top right example is basically made from a 50/50 solder of Pb-Sn (lead-tin) composition.

The original enlisted versions of cap and collar CAF insignia have an elemental composition of primarily Copper, Nickle and Zinc often called “German” metal. Based on initial measurements of several period pieces of CAF cap and collars, they all exhibit similar ratios in their major elemental components.
To illustrate the EVO’s output, a rough graph and semi-normalized elemental weight% values of one replica piece is illustrated. Further calculations and assumptions to normalize all readings were required to give a final “quantitative” estimate of the various elements present. The microscope doesn’t analyze the entire badge; only a very small, sub mm portion selected by the user and chosen to be representative of the object under study. The area is selected to be “clean” from surface contaminants; oxidation, sulfonation, the initial organic lacquer applied to these insignia to help preserve luster, grease and dirt, etc.

One of many interesting side observations that came out of this study was that at least some original enlisted CAF monograms had a trace of surface silver plating presumably to highlight that component. The low res SEM image shows the valleys and ridges on the top of the “A” in the CAF monogram. Visually through the SEM eye, one can observe a difference in the composition as demonstrated by a shade and texture variation and further borne out in the analysis at the points of the barely visible, green, overlaid numbers 2 and 3. The lower recessed layer contained regions indicated at over 95% silver while the majority of the monogram was the same composition as the main insignia. This suggests a very light silver coating on the NCO monograms which has worn off on the higher relief regions; more sampling of different pieces would be required to confirm this as a general statement. Also noted in passing is that the monogram pin is composed of 100% copper, probably because it was easy to solder onto the monogram and easy to rivet to the body of the badge.
I was also able to briefly look at some replica CAF pilots wings (I have four, clearly different replica variations but all possibly formed from the exact same duplicated die). This will be discussed perhaps in a submission to the MCCoC Journal down the road.

Other collectable areas such as fine art, stamps and sports memorabilia have respected recognized experts, technology and organizations where one can send their rare and valuable items for authentication and certification. Perhaps it’s time our field offered such a service too? Maybe this instrument will play a role in that in the future.

Regards,
Wayne Logus