Pace Technologies TERAPRESS TP 7500S, Instruction Manual, Page: 34 / 59

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ▲
I
NSTRUCTION
M
ANUAL
TERAPRESS TP 7500S
Mounting Press
Please read this instruction manual carefully and follow all installation, operating and safety guidelines.
3601 E. 34th St. Tucson, AZ 85713 USA Tel. +1 - 520 - 882 - 6598 Fax +1 - 520 - 882 - 6599 email: pace@metallographic.com Web: https://www.metallographic.com
7.1.2 Acrylics
The main application for compression mounting acrylics is based on their excellent
clarity. This is particularly important for locating a specific feature within the specimen
mount. Additionally, the edge retention is increased with acrylics over phenolics due to
its superior hardness.
TIP: A common problem, known as the “ cotton ball ” effect, can occur with
thermoplastic resins if they are heated to too high a temperature too quickly. This
causes a liquid layer to form around the unmelted resin giving it the appearance of a
cotton ball in the middle of the mount (see figure 7 - 10). To avoid this problem, it is
recommended to mount at a lower temperature (120 - 140°C), or to utilize a Soft Start
feature that preheats the resin and sample to a lower temperature (120°C) before the
mounting press pressurizes. To correct this problem after it has already occurred,
simply put the mount back into the mounting press for another cycle. Eventually, this
will eliminate the “ cotton ball, ” as can be seen in Figure 7 - 10.
Figure 7 - 10 The “ cotton ball ” effect observed in acrylics. The leftmost mount shows
the cotton ball when it first forms, and the remaining three show the result of
reheating the same mount through multiple cycles. As can be seen, the cotton ball
dissolves with temperature over time.
30