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**Thomas Durante** · 06-12-2013, 07:33 PM

Another reason I am thinking the FLL minesweeper might be Cupal is the appearance of a distinct line on the edge of it. This is exactly how a Cupal badge looks, with the dividing line between the copper layer and the thick aluminum middle.

Odd thing is that the top layer looks white, but yet the obverse is clearly gold color

Is it possible that this is a Cupal badge, where the top and bottom copper layers were finished white first, then the obverse wreath was finished with a gold top coat??

Tom

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1.4.3_FLLaluminum.jpg (31.2 KB, 125 views)

**Norm F** · 06-12-2013, 09:40 PM

Originally posted by Thomas Durante View Post

Another reason I am thinking the FLL minesweeper might be Cupal is the appearance of a distinct line on the edge of it. This is exactly how a Cupal badge looks, with the dividing line between the copper layer and the thick aluminum middle.

Odd thing is that the top layer looks white, but yet the obverse is clearly gold color

Is it possible that this is a Cupal badge, where the top and bottom copper layers were finished white first, then the obverse wreath was finished with a gold top coat??

Tom

Intriguing question Tom. I don't mean to hijack this thread on Martin's fine Cupal PAB, but in the interest of continuing the Cupal discussion I'll show some closeups.

The Minesweeper is not simply anodized aluminum. You're second observation was correct, both the obverse and reverse have a thin layer of some material which has a white finish on it. I can't see any coppery tone to this layer though, nor any green corrosion. You can see this thin white coloured layer is on the entire reverse and on the entire obverse waves of the obverse feature. It's apparent on the horizontal waves of the obverse feature but then a gold pigment is applied to the wreath overtop that layer and a silver pigment to the central water fountain.

So it is "Cupal-like" in that it seems to be an aluminum sandwich, but it appears to be on white bread instead of rye?

Is there any precedent for Cupal silver-grade Heer awards where perhaps the copper layer appears white instead?

Best regards,
---Norm

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**Norm F** · 06-12-2013, 09:40 PM

more closeups

Attached Files

**Norm F** · 06-12-2013, 09:46 PM

shows the spill-over of the gold pigment from the wreath on to the aluminum core on the edges.

Attached Files

closeup3.jpg (236.9 KB, 127 views)

**Norm F** · 06-13-2013, 08:24 AM

Here's a thought. This coin is apparently cupronickel (aka neusilber, nickel silver, "German silver") an alloy which typically has 60 to 75% copper, a variable amount of nickel and zinc and other trace metals.

For the Minesweeper, I wonder if we could be looking at a form of Cupal which uses cupronickel plating instead of pure copper? Just speculation.

Best regards,
---Norm

Attached Files

f_heller1913-1914.jpg (14.7 KB, 120 views)

**Thomas Durante** · 06-14-2013, 06:36 AM

Fascinating Norm! I have never seen anything like the silver-colored CUPAL material on that minesweeper. It look exactly like CUPAL, but just made with a silver-colored layer instead of copper. I think your speculation about the "cupranickel" is right on, although I cannot find any reference about a material like this being used on WW2 badges. We can find period references to CUPAL in uniformarkt, but not cupranickel as far as I have seen. But regardless, that is exactly what that material must be.

I don't think this is hijacking Martin's thread. At a minimum, this minesweeper helps prove that the Assmann PABs have a copper layer on the reverse as it is more evidence that fittings could not be soldered directly to aluminum. Especially with very small bases plate areas like we see with the FLL catch and the Assmann hinge, etc.

Tom

**Norm F** · 06-18-2013, 08:29 PM

Hi Tom,

I've been looking at some high powered closeups and now come to a different conclusion.

Although not visible in hand to my failing eyesight, when I enlarge the high-res photos I can see green verdigris in areas of wear of the white finish on the reverse, near the edges of the solder and the highlights of the wreath. Furthermore the dark brown/black spots on the reverse could very well be patina on aged copper.

I'm now thinking this is good old fashioned CupAl after all. The stock material seems to be manufactured with a thicker layer for the intended obverse and a very thin layer on the less important reverse (reducing cost and copper use). It seems that the copper is plated with a white finish which provides a better substrate for the application of the gilding of the wreath and the silver finish to the water fountain.

Fascinating!

Best regards,
---Norm

Attached Files

**Norm F** · 06-18-2013, 08:30 PM

more verdigris

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**Norm F** · 06-18-2013, 08:49 PM

Cupal is still made in Germany today:
http://www.cupal.de

A an old thread with some more info on Cupal and clad metals in general:
http://dev.wehrmacht-awards.com/foru...d.php?t=515026

Best regards,
---Norm

**Thomas Durante** · 06-19-2013, 07:00 AM

Hi Norm,

I am not so sure. I like your earlier thoughts that it is some type of "white metal cupal".

My reasoning is that I think we would see more copper color on the worn areas. Surely some of the silver plating would be worn off of these areas, revealing the brown copper layer. I have a few CUPAL pieces with silver plating on them. It doesn't take much wear at all to show the brown copper layer, so unless this minesweeper has a super-thick silver plating that is amazingly resistant to wear compared with all other cupal badges, then I think we are looking at a different metal here. I will show one of these badges tonight when I get home. It is practically mint, but yet on the extreme high points there is a little wear and you can see the copper color plain as day. I just don't see anything like that on this minesweeper.

Whatever this silver-colored layer is, it could still be made mostly of copper. But an alloy mixed with nickel or some other silver-colored metal to turn it silver color. Nickel Silver for instance is mostly copper, but with a little bit of nickel and zinc added to it to turn it a silver color.

That would explain why we see verdegris, because this "white metal layer" has copper in it. Also the solder could have some copper mixed in it.

Tom

**Norm F** · 06-19-2013, 08:52 AM

Hi Tom,

Well, I've got a parallel thread running on another forum, and Skip who has the same type of minesweeper just posted this morning. Being a braver man than I, he took some sandpaper to the edge.

Here is a quote of his findings and the image he posted showing the area:

"OK, this wasn´t so easy.
I took some sandpaper and rubbed a little across the top wing edge. So what do we have.
At the very top we have the thin copper layer. Just above that we have a silver colour that was covering the copper, very effectively as well I may say. The rest of the badge shows no sign at all of copper, only the area I rubbed with sandpaper.
Just behind that silver layer is the thick aluminum plate.
So indeed a cupal badge in the end."

Like he says, the white layer (he calls it silver) is very effectively applied. Regarding the "copper in the solder" idea, the veridigis is apparent only around the outer edge of the solder on the badge reverse, not on the surface of the mound of solder.

In light of all this, I believe we are indeed seeing a form of Cupal here (which is what you already suspected back in post #30

).

Best regards,
---Norm

Attached Files

FLL Cupal Minesweeper.jpg (68.3 KB, 77 views)

**Thomas Durante** · 06-19-2013, 09:18 AM

Very good Norm (and Skip, wherever you are

So CUPAL it is, amazing how efficiently applied that silver finish is.

Getting back to the whole point of this thread.....I am still of the opinion that there is a copper layer on the back of the Assmann PABs (and any CUPAL badge for that matter that has soldered, brass fittings). The layer may be super-thin, but it is there IMO and was needed to be able to solder the hardware to.

Tom

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