Tom
**Member** 
Posts: 28 
What I collect: Stamps from all countries that show wildlife.
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Post by Tom on Mar 9, 2016 3:24:43 GMT
Hi, everyone. I hope I have this in the right place. Also, I searched the Forums for this topic but didn't find it. One of the dealers I buy glassine envelopes from has a notice on their website that they will not offer any U. S. stamps issued after 2007 because of possible gum staining on these stamps arising from changed stamp specifications by the U. S. Postal Service. Apparently, the Postal Service has switched to a system that they tried on the 1974 10-cent Christmas Dove stamp (Scott #1552). The dealer's notice states that after a few years the gum began to bleed through to the front of the stamp so that now most all the mint examples are severely stained and damaged by the adhesive. The notice also states that many U. S. collectors have cut off their collections at the year 2000 or so because of this problem. I have not seen any information about this issue anywhere else and all the online dealers I'm familiar with sell U. S. stamps up to the current year. I would like to know if anyone knows anything about this matter or if it's just a lot of nonsense. Thanks in advance for any and all enlightenment. Link to Dealer Notice |
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khj
Member 
Posts: 1,524
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Post by khj on Mar 9, 2016 5:16:37 GMT
The notice is puzzling.
Scott US #1552, the 1st US self-adhesive postage stamp (1974 10¢ dove weather vane), used a rubber-based adhesive. That is what caused the stamp to stain.
All subsequent US self-adhesive postage stamps use an acrylic-based adhesive -- which do not "stain" stamps, but do suffer from cold-flow issues and also may cause some paper to become translucent over extended periods of time under certain conditions. The latter is a potential headache for cover collectors. Having used different types of office supplies over the years, I HAVE seen this happen with self-adhesive labels, but so far I've never seen this happen with the actual self-adhesive stamps nor with used self-adhesive stamps still affixed to a cover (although I have heard statements that it has happened with older self-adhesive stamps on certain envelopes -- but I cannot give a specific quote/example nor seen a picture showing this).
Because of the translucency problem, a primer layer is typically used before applying the acrylic-based adhesive. The primer layer is water-soluble to an extent, depending on the formulation/thickness... used. It is correct that USPS no longer requires a water-soluble layer. But that doesn't mean the printers won't use one -- they are simply no longer required to use a fully-water soluble primer.
Bottom line: rubber-based and acrylic-based pressure-sensitive adhesives are 2 different beasts, and there should be no comparison made between what happened with the 10¢ dove weather-vane and what may happen with other US self-adhesives.
The dealer notice, in my non-expert opinion, seems to be a combination of facts and incorrect information, mixed in with some observations that I think are insufficient to come to the rather drastic decision they have reached. If they wanted to be consistent or logical, they should be more concerned about not selling the early 29c self-adhesives first, rather than stopping the sales of 2007 and later stamps.
The early 29¢ self-adhesives (especially the coil versions of eagle/shield...) DO pop off the liners, and sometimes become very weakly self-stick. I believe this is a storage issue, as the ones I have that exhibit this problem were either stored flat underneath an acrylic plate on my desk (i.e., under long-term pressure) or exposed to elevated humidity for long periods. Only my 29¢ self-adhesives seem to exhibit this problem. But I would think that this is a potential problem for all the self-adhesives -- so, just like for water-activated gum, don't store your self-stick panes stacked up.
Bottom line for this problem: I think the problems the dealer was having is related to the storage history of the stamps they were using, not a general problem.
I no longer maintain a general collection of mint US issues after the year 2000 -- but NOT for any of the reasons given by this dealer. I don't know that many modern mint US collectors, but I haven't heard any of them stop stop their collection at 2000 for fear of self-adhesive stamps staining. I wished this dealer would have cited more specific examples, either as literature citations or quotations. But I did notice the dealer provided the usual disclaimer at the end of their phrase: "Due to these developments and other factors..." Personally, think the "other factors" are much more likely the reasons.
All that being said -- it is correct that acrylic-based adhesives are NOT archival. They will interact with many types of paper over time and make the paper translucent. But under proper storage conditions, I think we would degrade long before the stamp does.
Just my opinion.
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Ryan
Moderator 
Calgary, Alberta, Canada
Posts: 2,749
What I collect: If I have a catalogue for it, I collect it. And I have many catalogues ....
Member is Online
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Post by Ryan on Mar 9, 2016 11:20:41 GMT
The dealer notice, in my non-expert opinion, seems to be a combination of facts and incorrect information .... Kim states his opinion - I'll state my guess! I think this is just a guess by the dealer that the non-water-soluble adhesive (more correctly, the primer layer as described above) found on many post-2007 stamps means that the adhesive is the same as what they tried in 1975. And, as Kim says, that isn't true. I keep a spreadsheet for the purposes of determining whether I can soak the U.S. self-adhesives in water or not. There are some pre-2007 issues that can't be soaked but they're relatively uncommon (and in some cases, those older stamps can't be soaked due to excessive curling & resultant crinkling in water, not because they won't come loose). For example, in the 37 cent letter-rate era, I have 4 different issues I won't soak in water (not counting any non-letter rate stamps, my lists are organized according to face value, not according to date or catalogue number). In the 39 cent era, I have 3 different issues I won't soak in water. But in the 41 cent era (started in April 2007) I have 14 issues I won't soak, and for anything with a 2009 or later date on the stamp, I won't even bother trying to soak it because so few of them come loose in water. Those head straight for the pile that gets removed with chemicals and gets further sorted into groups of stamps that either will or will not tolerate a post-soak in water (again, due to curling and crinkling). Ryan |
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reena
Member
Posts: 352 
What I collect: US Federal Duck Stamps
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Post by reena on Mar 9, 2016 11:34:49 GMT
Ryan,
Since you are the soaking king, would you be willing to share that spreadsheet? I will send you my email. I'm rather guessing you have it in Excel? If so, I'd love to see it.
Thanks
Reena
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Ryan
Moderator
Calgary, Alberta, Canada
Posts: 2,749
What I collect: If I have a catalogue for it, I collect it. And I have many catalogues ....
Member is Online
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Post by Ryan on Mar 9, 2016 12:20:41 GMT
Since you are the soaking king, would you be willing to share that spreadsheet? I will send you my email. I'm rather guessing you have it in Excel? If so, I'd love to see it. I can send you an Excel copy, certainly, either .DOC / .DOCX or .PDF (the spreadsheet is optimized for printing, so it's easier to deal with the columns when it's shown as it would be printed - I'd recommend the .PDF version unless you plan to further update the spreadsheet yourself). I had made the offer to send out the spreadsheet earlier (during a time you were away from the forum, I think), but interest was, um, modest ... The spreadsheet is, of course, a continual work in progress. I didn't start it until I decided to start attacking the non-soakable issues, so I'm sure some of the older ones I haven't come across recently have passed my eyes at some point in the past. I'll get those updates made when / if I ever get around to sorting through those! Ryan |
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reena
Member
Posts: 352
What I collect: US Federal Duck Stamps
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Post by reena on Mar 9, 2016 19:57:10 GMT
Super, you have mail. Thank you very much.
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Post by carabop on Mar 9, 2016 22:56:19 GMT
May I also have a copy of your spreadsheet too Ryan?
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Ryan
Moderator
Calgary, Alberta, Canada
Posts: 2,749
What I collect: If I have a catalogue for it, I collect it. And I have many catalogues ....
Member is Online
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Post by Ryan on Mar 9, 2016 23:16:13 GMT
Certainly, just send me a message with your e-mail address. I won't get around to it until later tonight though, I'm just heading out the door now.
Ryan
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scb
Member
Inactive
Now at 100,000+ worldwide stamps, and progressing one stamp at a time towards the 200K
Posts: 313
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Post by scb on Mar 10, 2016 5:34:19 GMT
I'll chime in my 5 cents worth... Not knowing much about modern mint US stamps, but I do have plenty of experience of modern Finnish (self-adhesive) stamps.
Yes, the gum can bleed through as described. It just converts to 'sticky' grayish stuff that flows through on both sides of the sheet and stains (and sticks on everything).
Alternatively it tries as 'yellow gunk' and the stamps falls itself.
The first can happen in just few weeks (usually involves exposure to heat/sunlight); the latter is when storing stamps longterm in normal 'collector conditions' . Have seen stamps fall/peel off from postcards and clippings that were just 3-10 years old.
So based on what I know of Finnish stamps I would say it's possible. And yes, it scares the **** out of me when thinking long term storage. Fortunately my interest lies in used stamps only and this will likely solve the 'unsoakable' problem if I just live long enough, LOL.
-k-
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