The Rounder - Technical Aspects

[Dietrich Maerz]

Okay- Thanks-

I can understand what you are saying about differences in carbon. I will send a note to Warren at ISU for further clarification as well. Thanks

Tom,

all you would need is the percentage of carbon of each cross. Marc got this during his tests, unfortunately I didn't get it either!

Dietrich

[Larry L]

Dietrich,
Compare the paint pigments (grains) of rounders with other proven crosses paint (for example those WW1 Godet and WW2 Junckers).

You said that rounders paint is propably even smoother, this may or may not be one aspect towards defining rounder as a fake/real.

Grains of paint should be more non-uniform and come in different size and shape in those 60 year old pieces than more modern paint.

Propably this paint comparing doesn't lead anywhere because there are "only" couple of tens years between, but it is worth to check.

This is one aspect when checking art forgeries.

More about the paint later,

L

[Sonderkommando]

Dietrich,

I have been following these threads with great interest and I notice the main area that is being concentrated on is the chemical make-up of the paint used in the cores of these crosses.

Can I make a suggestion and say that another area that has not been touched upon is the solder used to join the frame halves. Would it be worth examining this and testing it for its chemical make-up and seeing if there is a major difference between known pre-45 crosses of all types and the Rounders?

Other than this, I can add no real constructive help.
Keep up the good work,

Regards,
Brett

[Marc Garlasco]

Brett,

The problem is getting to the solder as in most RKs it will be covered by silver. I tested a cross solder where there was enough wear to reveal the solder layer and it was mostly lead, with tin.

Marc

[Sonderkommando]

Marc,

It is a shame it is so hard to get to as I was thinking along the lines of the lead/tin ratio maybe being a different percentage compared to modern solder.



Regards,

Brett

[Dietrich Maerz]

Larry,

here is the greatest magnification I can photograph. The structure itself (grainy) is the same but the Rounder seems to be finer or having more particles.

Dietrich

[tom hansen]

Here is what Warren from ISU emailed me regarding the paint-


They are partly right but also quite wrong. Here are my several replies.

If I was comparing two samples and one reported 1.4% Ba and the other 2.7%,
I would temper my conclusions. Hoiwever, even a two-fold difference like
that will be hard to ignore due to differences in C levels. A 10-fold
increase indicates something markedly different. I cannot imagine that
including the C would put those levels into the same ballpark.

We have difficulty measuring carbon directly because it is such a light
element. We can see it with our detector, but the corrections for
absorption effects are severe and we are not very confident of the numbers.
We usually leave out the C, when we can, and compare the other elements one
with another. For example, if the Ba/Si ratio is markedly different between
two samples, then I would confidently say the samples are different. We
also have the spectra available and can overlay two different samples and
show the gross difference in Ba/C ratios without correcting for matrix
effects.

I would beware of surface condition differences between samples. If one is
pristine and the other has been carried around for some time, we would see
a difference. A pristine sample might have a thin layer of organic covering
most of the filler particles. There would probably be a few high spots
poking through, but a thin carbon layer would cover most particles. Since
EDS only penetrates a couple of microns (0.001 mm) into the surface, we
would not see much of the filler particles but just the organic binder.
However, after some use (or a light scraping) we would see filler and
pigment particles exposed on the surface. If there is a big difference in
particle size, we would see signals from the small particles first followed
by more signal from the big particles as more of them get more exposed.

I think we established last time that not all producers used the same
pigment. That is unfortunate because until we can say that we have a
fingerprint for all the valid pigments, we cannot rule out a pigment as a
counterfeit just because there is some difference. We would have to rely on
some other inconsistency.


Warren

[Marc Garlasco]

Tom,

I must say it is very nice of Warren to continue to be interrested in our hobby! He has been very nice in helping me as well.
Marc

[Dietrich Maerz]

... However, even a two-fold difference like
that will be hard to ignore due to differences in C levels. A 10-fold
increase indicates something markedly different. I cannot imagine that
including the C would put those levels into the same ballpark.
Warren

Tom,

that's exactly what I said.

"And I'm not saying that the Rounder or any other cross has such a high or low percentage of C, all I was saying is that one cannot compare the table numbers directly and that by making them comaprable the ratio will most likely drop"

and

"And, again, I clearly pointed out in the beginning of my thread that the paint is different. I'm sorry if I left out something that would lead people to wrong conclusions..."

However, the most telling statement from Warren is this:

"I think we established last time that not all producers used the same
pigment. That is unfortunate because until we can say that we have a
fingerprint for all the valid pigments, we cannot rule out a pigment as a
counterfeit just because there is some difference. We would have to rely on some other inconsistency."

This is what I was saying all along. The paint is different, yes. But is it 'fake' because it's just not like 7-8 other examples? No! Or at least not as long as we have a lot more samples!

Thanks Warren for this clarification! Much appreciated!

Dietrich

[Larry L]

Thanks Dietrich,

As I suspected, nothing really conclusive can be said regarding the paint.
Rounder manufacturing date could be anything between circa. 1940-1980.

Also, Tom Hansen's post from Mr. Warren seemed to answer paint issue quite well. It currently doesn't lead us any further without more studies.

But, for example 1813 versions of Iron crosses can be authenticated by their paint .

L

Larry,

here is the greatest magnification I can photograph. The structure itself (grainy) is the same but the Rounder seems to be finer or having more particles.

Dietrich

[Blitz]

I'm happy that atleast one direction is cut out, so the emphasis can be directed elsewhere.

Ps. Maybe I should try and locate a SEM in Finland and test my 1813ek2..

[Brian S]

1.11.1941 (Nov. 11 '41) manufacture of RKs for private purchase ended.

Feldgrau.com: RKs awarded to 1.11.1941 = 1,027 out of 7,116. 14% of all RKs awarded up to this time.

8 manufacturers (SL, KQ, Godet, Juncker, Deschler, Zimmerman, Schickle, Rounder) produced 14% of all RKs. Assume even distribution and 1.75% by 'Rounder'.

Even distribution 125 of all awarded RKs ended up with Rounders by 1.11.1941.

You're looking for vet family Rounders.

1 in 57 at most would be Rounders from the total pool of vet pieces.

Not being heavy handed but can anyone argue S&L and Juncker made the lion's share of crosses. Given that I'd guess, now it's an educated guess, at most 1 in 75.

[tom hansen]

Dietrich-


Sorry, I was not disputing your assertion that the paints are different. Just the side issue is the comparison of trace elements between different crosses was confusing. I can see you point regarding the carbon content and felt as though Warren would be able to provide further information that would clarify the issue as well. I do not know crap about that stuff and am relying upon the information which has been transmitted to me, so it is good to hear the views of someone who does this everyday and is an expert in the filed.

As Warren has pointed out, the SEM can tell differences in paint reliably. The rounder clearly has different paint than every other RK tested. When there are differences, it is up to us to find out and discuss potential reasons as to why they are different. This is the whole reason for Marc's impetus to use IR spec. Perhaps that will show further information and differences.

Larry- I think the assertion that nothing can be concluded about the paint via SEM is not correct. The paints are different and Warren has pointed out that the differences in trace elements are valid and substantiates that the paints are different. The question is- what does that mean?

[Dietrich Maerz]

From the first dates the SEM results came out, there was never any dispute as to whether the paint is different or not. It cleary is. And so is the Lazy 2 paint, the Godet paint and most likely a lot of other not yet tested.

I'm glad that we finally can all agree on this!

Dietrich

[tom hansen]

Here is a further note from Warren regarding the paint


Thanks Warren!
>
> So basically what you are saying then is
>
>1. The differences, both qualitatively and quanitatively, with regard to
>trace
>elements are real and can be compared between crosses as valid differences

14% is far beyond a trace amount. I would put the limit at 1% or less.
I think the differences are valid between crosses analyzed the same way in
the same lab. It is more difficult to compare crosses analyzed in different
labs by different operators. I would be more confident if both operators
are very competent. Unfortunately, it is very easy to get numbers out of
these x-ray analyzers. Some of the results are even worth some attention. I
would probably judge 4% and 8% to be significantly different if analyses
were done the same way in the same lab. I would give some benefit of the
doubt to such differences in analyses if they were performed in different
labs.

>2. The differences in carbon, while very possible, would not be enough to
>impact comparison between the crosses

Not at these levels of differences.

>3. Differences in paint per se cannot determine whether an item is fake, but
>simply provide measurements in elemental composition between known originals
>and the item in question.

Yes, but there were so many types of known originals in your case. It makes
it harder to rule out fakes as opposed to a case where there is one tight
standard for all. If a sample differed from that standard, we would not
also have to compare it to a number of other standards before ruling it a
fake.

> Is that correct? Would not the marked differences then in the paint
> noted be
>an indication that something is amiss?

Yes, yes. We are seeing some marked differences between samples that need
to be explained somehow. The best way is probably to label the different
one as a forgery. I would put the burden of proof on them to show that
similar composition exists in a piece known to be authentic.

>Thanks!- Tom H


You're welcome. If there are some particular entries on the web log or by
e-mail that challenge my results, I would be interested in reviewing them
and perhaps responding directly.

Warren