Question Regarding "Fold-O-Hinge" Color

I have never used any hinge other than Dennison's.

Jack Kelley

I really don't think the thickness of the glassine paper is the issue. I'm convinced it's the glue Dennison used. After all, it's the glue we're always talking about when we say the hinge ripped the paper when we tried to remove it. In the "olden days" when glue was made of animal parts (old horses = glue factory), glue was different than the purely chemical glue manufactured today. Modern attitudes make it far less likely for companies to make animal glue using horses, pigs, or whatever. From an online "Slate" article: "Animal glue, popular for thousands of years, has fallen out of fashion in recent decades. Over the second half of the 20th century, synthetic glues have become more advanced, as they are cheap, uniform in quality, and have longer shelf lives." Apparently, though, some "animal glue" is still made, and it's preferred by bookbinders. So why this glue can't be used for hinges -- assuming that the new hinges use different glue, of course -- I don't really know.

But whatever the reason, new stamp hinges stick much more permanently. That would be considered a very good thing if you made glue. However, in the world of stamps, that's not so good. We like our glue to hold well, but also be easily removable. Like rubber cement -- which I sometimes wonder about as a hinge substitute(?). Or is that nuts? Whatever glue (or paper) Dennison used, it was just right for mounting -- and removing-- stamps. It held well, but it removed smoothly without tearing anything. It's a bit like the glue on "Post-It" notes, but I've been told that apparently that glue is not very permanent which Dennison hinges were if you left them alone.

Why don't we know the composition of the glue Dennison used? It's a mystery. You'd think an average chemist could scrape off the back of a few Dennison hinges and determine exactly what kind of glue they used. They do that sort of thing in police shows all the time! So the real question, I suppose, is why no one has taken that easily-discoverable composition of Dennison's glue and re-manufactured it? If any collector is also a halfway decent chemist, or if you know one, maybe you'd like to run the test and let us know. Or ask your kid to do this for their next Science Fair. Please.

I've read a few times that some believe the adhesive was "textured" on a Dennison hinge. Perhaps someone with greater knowledge of chemistry can correct me, but it doesn't make sense to me that texturing gum would make any difference. Once the adhesive liquefies, whatever properties existed when it was a solid disappear.

You should be able to analyze it using a mass spectrometer, which would determine what compounds are in the glue. I guess one issue, as mentioned above, the current market for such a product. The other, as you say, if there's glue in there made from an animal, that's not likely to get made nowadays.

I also wonder how long the current supply on old Dennison hinges will last?

It's buried somewhere on one of the older SCF threads, but the texturing is a ripple effect, and the thought was that if lightly moistened, that made it easier to peel the hinges. So we need a mechanical engineer instead. But maybe it comes down to not moistening all of the hinge, just the high or low spots (depending on how wet the hinge was made). If you soak a Dennison, it often sticks down as hard as any other. And peeling a Dennison that was lightly moistened, you'd sometimes still see the texturing on the gum.

With current hinges (and envelopes that still have water-based gum), if you try to be too light on the moistening, they won't stick. I'm supposing that to avoid sticking in storage in humid weather, that's done on purpose. So you do have to disturb the gum surface with enough moisture to get things to stick. The textured Dennison gum might help with activation, too, then.

Dennisons weren't immune to bad storage. I'd avoid buying the packages that were like flat little bricks, though I was given some on occasion. Some of those hinges could still be usable where Fold-Os badly stored from the same store stayed stuck.

I've bought over 30 packs of Dennisons off of ebay over the last five years. A few of the packs had a good number of hinges that were curled together - making it a bit difficult to use. Some were also "folded". Those that were not easy to use got put into a separate envelope, which is now about the same quantity of 1 1/2 packs. Ha, someday this may hit ebay again.