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3.5.6 Fire Polishing
The P-97 micropipette puller allows you to perform light to moderate fire polishing of pipette
tips but does not have a provision for visualizing the pipette tip during the heating process.
The extent of the heating required to attain the desired degree of polishing must be
empirically established.
What distinguishes a program for polishing from other programs used to pull pipettes is the
use of a Velocity value of 0 (zero). To program the instrument for the fire-polishing mode, try
entering a program as follows:
HEAT PULL VELOCITY TIME
Ramp - 50 0 0 250
Pressure does not matter because the air supply is never activated in this mode.
When executed, this program will behave as follows: the Heat will turn on for the duration
set by Time. Each Time unit is equivalent to 10 msec. Therefore, in the above program, the
Heat will turn on for 2.5 seconds.
The procedure for polishing is as follows:
1. Pull a pair of pipettes with the desired pulling program. After the pipettes have been
pulled, keep them clamped in the puller bars.
2. Reset the puller and select your polishing program (as above).
3. Manually push the puller bar (with the installed pipette) back towards the filament, and
use the Fire Polish Spacer block described next. Using the adjusting screw on the top of
the spacer position the tip of the pipette just inside the edge of the filament.
4. Press Pull and the filament will heat up for 2.5 seconds, exerting a polish on the end of
the pipette.
How much polishing occurs will be a function of the Heat value and the duration of that Heat
as determined by the Time value. You may need to execute the program multiple times to
achieve an appropriate polish. Experiment to determine how much Heat and Time are
necessary for the degree of polishing required.
The most important part of this procedure is manually positioning each pipette back into the
filament at the same relative position each time. The Fire Polishing Spacer allows you to
consistently reposition the pipette within the filament. The T-shaped aluminum Spacer has
an adjustable setscrew.
Figure 3-10. Side view of fire polishing spacer.
The Spacer/screw combination fits into the slot in the puller bar and fixes the puller bar
position. You adjust the screw position to set the position of the puller bar (and thus the
pipette tip). The more extended the screw is, the closer the pipette tip will be to the heating
filament.
When you have finished polishing the pipette, remove the Spacer from the puller bar.
P-97 FLAMING/BROWN MICROPIPETTE PULLER OPERATION MANUAL – REV. 2.43 - DOM (20161118)
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