Electroplating



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.

Sometimes the deposition of metal on gypsum or plastic matrixes is lasted as long as the thickness of each plate is less than half the thickness of the coin to be copied and then these plates are soldered by the entire contact area of the rear side.

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.


2 comments:

  1. 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!!

    ReplyDelete