Chapter 3: Theory of Operation & Safety Precautions
Product Service 1-800-522-7658
5
white plastic or similar), visible to the naked eye. The reaction must be
monitored to ensure that it is not allowed to continue for too long. If it runs
unchecked, the latent fingerprints can overdevelop and the chemical
images of the ridges will slowly grow wider until they overlap, obscuring
vital detail.
Generation of CA Fumes Through Controlled
Heating
CA adhesives have a boiling point of approximately 120°F (50°C). With
increasing heat, cyanoacrylate decomposition products begin to appear at
temperatures above 250°F (121°C), and when the temperature exceeds
400°F (204°C), hydrogen cyanide can be produced. It is therefore critical
to maintain a consistent, controlled heat throughout the development
process.
The CApture Print System uses a heater, controlled by a digital controller.
The user-programmed controller maintains the set temperature between
the minimum of 120°F (50°C) and maximum of 350°F (177°C). A redundant
safety switch limits the heater temperature to a maximum of 350°F (177°C),
in the event of a controller malfunction.
Clear Chamber
The clear chamber is made out of durable, shatter-resistant
polycarbonate. It protects the heater/filter module when the unit is being
transported, and allows an unobstructed view of the evidence during the
fuming process. While the clear chamber is resistant to many chemicals, it
is not resistant to CA fumes, and it MUST be treated with either Rain-X
®
or
Rain Block
TM
glass water repellent. Labconco has tested these two
treatments, and found they protect the clear chamber from CA fumes for
up to 20 uses, if properly applied, and the treatment is not disturbed.
Always follow the treatment manufacturer’s instructions when applying the
treatment. Labconco has not tested any other brands of glass treatment
chemicals, and cannot recommend their usage.
Two Stage Filter System
CA droplets and fumes are removed from the air in the clear chamber by a
two stage filtration system. The first stage of the filter cartridge is a
polyester loft particulate filter, having a Minimum Efficiency Reporting
Value (MERV) of 11, meaning it removes 65-79% of particles 1.0-3.0
microns in size, and more than 85% of particles 3.0-10 microns in size.
The second stage of the filter is specially prepared granular activated
carbon (GAC) that adsorbs any gaseous CA as the air flows through the
carbon bed. See Appendix A for replacement part numbers. Using the
recommended amount of CA for proper development, the filter should last
for a minimum of 100 fuming cycles (about 2 oz, or 57ml) before
replacement.
