Gamry Instruments MultiPort, Operator'S Manual

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Assembly--Sample Holder Assembly
14
Sample surface finish and other sample preparation are critical if you want to obtain reproducible results.
Consult the corrosion measurement literature for details about the handling of corrosion test specimens. Most of
the surface preparation techniques used for weight-loss coupons are also applicable to electrochemical test
specimens.
A diagram of an assembled Sample Holder can be seen in Figure 5. A threaded rod is used to hold the assembly
together and to provide electrical contact with the metal sample. The PTFE Compression Gasket is used to
prevent leakage of solution into the interior of the glass rod. The sealing surfaces of this gasket must be smooth
or a good seal cannot be obtained.
Put together the assembly loosely before tightening the Hex Standoff. Consult the diagram in Figure 5 for the
position of the Sample Holder components. The centering washer has a small protrusion on one surface; the
other surface is flat. The side with the protrusion side faces into the glass tube.
Tighten the Hex Standoff at the top of the assembly while you hold the metal sample on the other end. Only
tighten the assembly finger-tight.
A small amount of bending in the glass tube may occur when you tighten the assembly. This is normal and no
cause for concern.
Caution:
Never use a wrench to tighten the Sample Holder Assembly. Doing so can
damage the PTFE Compression Gasket or even break the glass tube.
Take great care to insure that the surface of your test sample is not altered prior to the test.
Avoid contacting the sample with your fingers. You may want to degrease the metal sample mounted on
the Sample Holder just prior to starting your test.