Forensic Analysis of PT/35b

Preliminary Results of Our Investigation (October 2015)


PT/35(b) is the critical piece of evidence that pointed the investigation towards Libya. As Richard Marquise himself said: “Without PT/35(b), there would have been no indictment.”

PT/35(b) may very well have been necessary to “solve the case”, but it was certainly not sufficient. It was also necessary to match PT/35(b) to the MST-13 timers which had “solely” been supplied by MEBO to Libya.

It turned out that the CIA was “fortunately” in possession of such a MST-13 timer (K1)which had been allegedly brought back to the US by some US Government employees following a visit to Togo in the fall of 1986.

Without the Togo timer, PT/35(b) could not have been identified and therefore there would have been no case, let alone  an indictment, against Megrahi and Fhimah.


Is PT/35(b) REALLY similar to the PCB supplied by Thuring to MEBO to manufacture the MST-13 timers delivered to Libya?


To be done…


“A printed circuit board (PCB) mechanically supports and electrically connects electronic components using conductive tracks, pads and other features etched from copper sheets laminated onto a non-conductive substrate. PCBs can be single sided (one copper layer), double sided (two copper layers) or multi-layer (outer and inner layers).” [Wikipedia]

“FR-4 glass epoxy is the primary insulating substrate upon which the vast majority of rigid PCBs are produced. A thin layer of copper foil is laminated to one or both sides of an FR-4 panel. Circuitry interconnections are etched into copper layers to produce printed circuit boards.” [Wikipedia]

The materials needed for the manufacture of laminates are glass fabric (filler), epoxies (resin), solvent and copper foil.

Fibre-glass Cloth

“Glass cloth acts as the main structural reinforcement in most laminates. The rigidity and strength offered by glass compliments the binding, encapsulating and insulative properties of the epoxy resin.  The singular fibre-glass filament is the building block with which glass clothes are constructed. These thread-like fibres are put together to form a yarn or bundle. Subsequently, like weaving of any other type of cloth, numerous yarns are woven together in the manufacture of cloth. Various combination of filament and bundle diameters, filament counts and weave density, among other variables, will resist in a multiplicity of glass cloth thicknesses and weights. Finally, glass clothes are coated with a finish that facilities resin impregnation of and bonding to the cloth.”

According to a FBI document date 20 August 1990 (classified SECRET):

“The Scottish Police have determined, after extensive investigation, that the green circuit board (PT 35) is single sided and composed of nine (9) layers of glass cloth, type 7628.”

A Memo from Det. Insp. Williamson dated 3 september 1990 states that:

On 14th February 1990 George Wheadon, Chief Technical Manager and Mr Paul Boyle. Laboratory Manager New England Laminates Company Skelmersdale Lancashire. I t I carried out an examination of the laminate of PT35. New England Laminates are one of the top manufacturers of copper clad laminates in the world. Mr Boyle removed a small cross-section or PT35 which was examined under a  microscope by  Mr Wheadon and himself. Their findings were that the laminate is constructed with 9 layers of American standard 7628 glass cloth which is very commonly used in the industry.

The MEMO goes on:

Though standard FR4 (fire resistant rating) glass cloth has been used in the manufacture of the laminate of Production PT35 the number of layers of’ glass cloth used may be a feature of importance. PT35 is constructed on 9 layers of glass cloth, the most commonly used method of production for this type of laminate board is to use 8 layers of glass cloth. This feature was identified by Mr George Wheadon, Chief Technical Manager, Nelco Laminates.

Here is a photo of a 7628 sample:

Epoxy Resins

“The function of the resin is to act as a ‘glue’ to hold the laminate together. Epoxy resins can be purchased from various vendors at various steps of manufacture. Epoxy resin can be had in a liquid form so that it can be concocted to upstaged resin using proprietary recipes and processes.  It can also be purchased in the advanced or upstaged state, wherein the solid resin, complete with hardness and catalysts, is ready for use in treating.”

According to a FBI document date 20 August 1990 (classified SECRET):

This glass cloth laminate is manufactured using a Bisphenol A epoxy resin cured with Dicyandiamide.

A Memo from Det. Insp. Williamson dated 3 september 1990 states that:

“The glass cloth laminate is manufactured using a Bisphenol A epoxy resin cured with Dicyandiamide.”

“A feature of any interest in the manufacture of epoxy resin would be chemical used in the curing process. the In the Case of Production PT35 the curing chemical is dicyandiamide. This is the most commonly used chemical for this purpose in the industry and does not assist in identification.”

SEE PT/35(b): Analysis of the resin at Ciba for all the details

Let us now move to the TIMELINE of PT/35(b) PART V

4 March 1992

According to their HOLMES statements, on this date McAdam and Buwert travelled to Ciba Geigy and interviewed John French, who removed from DP/347(a) a small sample, DP/505 (Crown label 407) to allow infrared spectrometry, and a spectrum, DP/506 (prod 346) was produced. Mr French then examined DP/12, a sample removed from PT/35(b), and subjected it to the same test as had been done for DP/505, and produced another spectrum, again labelled DP/506 (prod 346). French’s conclusions were included in his statement.

According to the police report the result of French’s analysis was that both samples from PT/35(b) and from DP/347(a) showed bisphenol A epoxy resin cured with dicyandiamide, both samples being made from chemically similar materials. The manuscript statement of French was prod 358.

He stated that on comparing the results, he was prepared to say that the sample was constructed using the same type of resin as the sample taken from PT/35(b). The same curing agent had been used, and both samples had been made using chemically similar materials. He said it was not possible to state that they had been made by the same manufacturer.

Of course, the real question put to Mr French should have been: do PT/35(b) and DP/347(a) come from an identical copper clad laminate?

Let us simply look at the IR Spectra once more time.

The answer to this question is simply devastating. It is a resounding NO.

PT/35(b) and DP/347(a) come from two “similar” but clearly different copper clad laminates. For instance, notice the presence of the 2200 cm-1 absorption line in the DP/347(a) spectrum which is obviously absent from the spectrum of PT/35(b).

Copper Foils

“Most foils used in FR-4 manufacture are electrodeposited type foils. These are manufactured by plating copper onto slowly revolving drum-shaped cathodes that are partially immersed in the plating solution. As the drum revolves, the plated copper deposit is removed from the cathode drum at one continuous speed. Varying the drum speed and current density helps to vary the copper deposit and consequently, the resulting foil thickness.”

According to the Williamson MEMO (03/09/1990):

“The copper used in the tracking is a standard thickness of 35 microns of 1 ounce weight.”

Quite possibly, Williamson meant to say that the foil was a “standard foil” with a thickness of 35 microns which is common in the industry.

Post Processing

“At this stage, the ‘raw’ foil becomes available, which is then subjected to various processes designed to increase the roughness of the matte side, thereby increasing its mechanical adhesion to the substrate. In addition, the foil is coated with a micro-thin film of protective coating to prevent oxidation of the copper during lamination and storage.”

The “standard” copper treatment consists of microscopic copper nodules deposited over the copper “teeth” on the bath-side of the foil. (see photomicrograph below)

To reduce oxidation and make a more thermally stable treatment, brass, zinc or sometimes nickel is plated lightly over the deposited copper nodules.

A further treatment in the form of a very light zinc chromate or other antioxidation treatment may be used to prevent oxidation of the drum or smooth side of the foil.

Copper adhesion is achieved by a combination of physical and chemical bonding. ED copper foil has a natural “tooth structure” formed during electro-deposition and the nodular treatment (see above) provides a locking mechanism when the resin coats and encapsulates the copper teeth/treatment.

Chemical treatment of copper foils can also enhance bonds. Many of the foils in use today have proprietary silane or other treatments which chemically enhance bond to a variety of resins.

Note: All copper finishes will not work equally well with all resins.  Optimization of lamination process and selection of the foil finish for each resin system is critical to achieving good bonds.

Here is a cross-section of PT/35(b):

And here is a cross section of DP/347(a):

According to Whitehead Precognition, Brass is clearly visible on PT/35(b). (Statement S5587H):

“The yellow Matte side colouration was evident, indicating the presence of a brass barrier layer.”

SEE DP/10 : Evidence of Fabricated Proof?

Michael Whitehead was also of the opinion that the copper foil for DP/504 was manufactured some time earlier than the copper foil for PT/35(b).

Whitehead’s manuscript statement (prod 359) gives further details of the testing he conducted, and explains that micrograph A shows in general the result of the preparation, and micrograph B shows the matt side topography of one of the peeled tracks at magnification of just in excess of 1000 times.

The statement records that the relationship of the dendrites to the base foil pyramids was representative of a product manufactured by Gould, but that the previous micrographs (DP/14) of DP/10, the sample from PT/35(b), suggested that DP/504 was manufactured earlier because the number of peaks per unit area was less that depicted for DP/10.

(NB. That is to say, this surely indicates strongly that  PT/35/(b) was manufactured later than the board provided by Thuring.)

There is indeed no doubt that the copper from PT/35(b) is not similar to the copper from the Thuring boards. Moreover, the difference is understood. In the very late 80’s and well into the 90’s, the industry modified the production of the copper and the laminating process to improve the adhesion of the copper to the board. The characteristics of the copper on PT/35(b) reflect this improvement.

The Watermark

The watermark “S I B” visible ( Well, at least visible to anyone except to the experts of the CIA and the FBI as explained in: The THURING Board Watermark: FBI Analysis ) on the main board of the MEBO MST-13 timers seems to indicate that these boards were produced by a Swiss branch of the ISOLA Company.

According to a well-informed source, THURING AG always ordered the Copper Clad Laminates from a Swiss branch of ISOLA: Schweizerische Isolawerke AG in Breitenbach. (SIB)


I. The “Thinning” of PT/35(b) is wrong. (Pure Tin vs Tin/Lead for the Thuring boards).

II. The density of the copper nodules on the “Matte” side of the copper foil is evidence that PT/35(b) was built on a copper clad laminate manufactured well after the time the THURING boards delivered to MEBO in 1985 had been produced.

III. The epoxy resins used in PT/35(b) and in the Thuring boards are obviously different. (Probably to take advantage of the higher density of the copper nodules in PT/35(b) as noted above.)

IV. The watermark on the board was incorrectly defined by the FBI as “21B” instead of “SIB”. (and this watermark was totally ignored by the CIA.)


Copper Clad Laminates

Understanding the PCB Laminate (ISOLA)

Statement of witness: Albert FRENCH

Applications of FTIR on Epoxy Resins


DP/10 : Evidence of Fabricated Proof?

The chronology of PT/35(b): 06/03/1992

The chronology of PT/35(b): 04/03/1992