I had an idea for an invention. There should be a handy marker to detect reblueing like the one used for fake currency. Some sort of litmus test!

That would have to depend on a chemical reaction to basically the same substances with different ages... That would be an interesting challenge.

One approach would be to somehow test the balance between the different forms of iron oxides. Rust versus magnetite. The more iron oxide deep in the finish, the older the finish.

Maybe!

George little shooter present! TKS

Those only react to the starch in the paper. Real currency isn't really 'paper', it's rag.

What you want for currency is an UV pen that will show the stripe and mini-writing on the stripe. The stripe is in different locations on the bill depending on denomination, and it's a different color too. Green on a twenty. :)

Thank You,

Rich is right, they're basically iodine markers. The swipe that turns black indicates starch. Starch was supposedly used as part of an obsolete counterfeiting process from the 20s, however some starch can be found in today's printer paper.

James Randi used to create a little excitement by sourcing a brand new Ben Franklin from the bank and spraying it with Niagara spray starch before he took it to a merchant with one of the bogus pens. It would show up as bad money in the test at the checkout counter, the police would be called. But the brou-ha-ha would be quelled after the bill was verified at the bank!:)

I Love This Place!!

Here is an invention to detect re-blue. These used to be used a lot in manufacturing, not so much anymore. Therefore they are fairly cheap on Ebay.

My experience is that all Lugers have some degree of finish loss/corrosion, even high-condition Lugers viewed with a microscope. On refinished pistols such areas are blued, on original pistols such areas are not blued.

Be careful. Many refinishers have caught on to this one, and are "re-whiting" this pin. Be suspicious of pins which are too bright--almost polished--and dead even with the surface of the toggle piece.

Originally these pins were simply cut off (lathe cut) from stock and pressed into place. They have a characteristic "teat" in the center, remnant of the cutting process. A pin end which is smooth has been removed and tapped back into place by a hammer. The pins were often pressed just below the toggle surface, and can be rimmed by grime. The pin faces do not really rust but they do considerably darken with age, to the extent that it is often extremely difficult to differentiate them from the adjacent blued surface. There is a slight color difference, which sometimes shows up a little better in photos than by eye.

--Dwight

Golly, Dwight, there are some sneaky folks out there. But, then an honest guy trying to restore his precious Luger will want to do the same thing. I have sure learned a lot in this thread from all the comments from the masters. :thumbup:

Sometimes a tricky call to make because of the natural darkening. I've noticed the little teat you mention, and its method of creation by lathe cut-off makes perfect sense. Strong magnification can be our best friend!