For this technique the forger creates a
matrix (for example by the casting method). The matrix will be created with the
non conductive current materials. On the surface of matrix thin layer of
conductive current material is applied (for example graphite). Then the matrix
placed in an electrolyte solution to be a cathode. Anode is a material the
forger wants to create a fake coin (copper, sliver, Pb-Sn alloy).
After
deposition of the desired metal layer is separated from the matrix and becomes
a part of the future coin. These parts are glued or soldered with or without
filling (lead filling, for example).
Obtained plates with precisely repeating
relief obverse and reverse of the coin are fitting to each other and connecting
by soldering to the rim so that the distance between them is consistent with
the thickness of the coin to be copied.
Some extremely rare coins made of three
parts: in addition to the plates of the obverse and reverse by the same way the
forger makes coin edge (ribbon that copies scan edge of the coin). Ribbon is folded
into the ring and soldered between the plates. Sometimes, instead of ribbon
reproducing authentic edge coin between the plates of obverse and reverse
soldered other ribbon with some randomly selected pattern or notch.
Usually these fake coins have the
following features compared to genuine coins:
1. Quite clearly visible place spikes on
the rim of plates or a band forming edge;
2. The Galvanic usually absent ringing
inherent in solid coin;
3. Visibly sag of averse and reverse of
the coin when you press on them;
4. Galvanic weight significantly less than
the normal weight of the coin to be copied.
Often a number of measures significantly
can improve the quality of Galvanic. By the interposition of filler plates
galvanic weight can be fit the weight of the coin to be copied. This could exclude
the deflection plates when pressed and could give some Galvanic ringing.
Galvanic silver and gold coins made of
copper, usually after final assembly plated by silver or gold. By this way place
spikes are disguised. Such improvements do Galvanic difficult to distinguish
from genuine coins and allowed to give some of them for the originals to fool
collectors.
Equipment and methods needed to prevent of electroplating coins purchase:
Magnifier, microscope (gluing or soldering
of the edge detection, surface roughness detection);
Continuity method of fake coin checking;
Weighting method.
Wow!! The blog you have written on electroplating is absolutely brilliant. I was searching for some good references when I happened to pop up on your post. Thanks for sharing this information with everyone. Keep blogging!!
ReplyDeleteThank you!
Delete