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Topic: PMG Holders and the Beilstein flame test  (Read 7224 times)
mmars
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« on: November 28, 2009, 04:31:10 pm »

I forgot that I have a U.S. note in my collection that is graded by PMG (shown below).  It's an unremarkable obsolete note that I bought in spite of it being in a PMG holder, not because of it (I just love the design).  The grade is F-15 and there is no mention of the note's several pinholes and one significant edge tear at the top of the leftmost vertical fold anywhere in the grade assessment.  I guess this is why many sellers prefer PMG and why many collectors will not remove notes from PMG holders.  Many, but not all.

After my previous post on BCS holders, I received an offer from a forum member willing to donate some empty PMG holders toward doing the Beilstein flame test for the detection of halide compounds in plastic.  One use of adding halides to plastic is to make the plastic softer (i.e. less brittle and thus less susceptible to breakage).  The down side of soft plastics like PVC is that chlorine is leached slowly over time.  Paper in contact with PVC plastic over long periods of time can become damaged.

My interest in testing PMG holders is due to the close resemblance to BCS holders that I tested and for which results were reported in another thread.  The main difference in the PMG holder is that the note is in direct contact with the housing, meaning there is no inner sleeve surrounding the note like in a BCS holder.  The style of the packaging is very similar to BCS, and the plastic looks and feels the same.  After posting this, I am going to remove the PMG note shown below from the holder and test it for halides via the Beilstein method.

{http://www.give-a-buck.com/special/allegany1-f.jpg}
{http://www.give-a-buck.com/special/allegany1-b.jpg}


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mmars
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« Reply #1 on: November 28, 2009, 05:51:29 pm »

RESULTS

*** Please keep in mind that this is one PMG holder being tested.  It would serve the discussion greatly to test several holders of different ages, and to have other people doing the same tests to verify the results.

I used a fresh piece of copper wire and heated it in the flame for about a minute, thus cleaning the metal surface.  I touched the hot wire to a piece of PMG plastic, causing some melting and vapor emission.  I returned the wire to the flame and did not observe any green colour nor any other colours that could indicate the presence of halides other than chlorine.  I repeated the test several times and derived the same negative result.  I retried the test with the BCS holders that I tested previously and observed a bright green flame.

So the Beilstein test that I performed does not prove that PMG holders contain any halides like chlorine.

I must add one anecdotal observation here, and it is this: the PMG holder felt much more rigid than the BCS holders.  The results of the flame test done on both company's holders seem to corroborate that the PMG holders are made of hard plastic while the BCS holders are made of a softer plastic.

These tests are not meant to be an endorsement or criticism of either grading company.

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Elwoodbluesca
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« Reply #2 on: January 08, 2011, 10:22:40 am »

I feel these tests reveal important compound data of the holders. I have had non-forum collectors and dealers talk to me about the results of the Beilstein flame test, as they are very interested in the outcome.

I think it as been made very clear that these tests are preformed, observations being posted and are non-bias. If someone chooses to interpret the results as an attack on the holder or grading company, you are sadly mistaking, and are ignoring the true results. If you have a better test, please make it known with the results.

This is useful data for the hobby, so keep up the good work for informing the collectors and dealers of the realities of life.

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