MG Chemicals
AppGuide
One company. Many solutions.
Protecting your circuitboard from moisture and humidity
We all know what happens when
moisture or humidity gets into
contact with electronics devices -
they stop working. Damage
generally occur at the circuit board
level. Moisture and humidity can
cause a short circuit. Short circuits
occur when water creates a bridge
across tracks and in some cases
this has resulted in arcing and fires.
Electronic devices may also
malfunction from traces being
corroded away.
FIGURE A.
CORROSION OF COPPER CIRCUITRY
FIGURE B.
BURNT PCB RESULTING FROM ARCING
EFFECTS OF MOISTURE AND HUMIDITY ON TRACES
SOLUTIONS
1
Conformal Coating
Conformal Coatings are most commonly used. They are
easy to apply and very effective at preventing your PCB
from corroding, short circuiting, or arcing. Simply clean
your board and spray or brush the product on. You will be
left with a board that is coated with a transparent coating
of approximately 1 mil thick (one coating).
Application Instructions
Shake well before using. Spray with an
even sweeping motion 6 to 10 inches
(15 to 25 cm) from surface. Spray from
different angles for proper coverage.
Apply 2 or 3 coats if extra coverage is
desired, waiting 5 to 10 minutes
between coats. For best results, apply
at room temperature (20ºC / 60ºF).
May also be applied in liquid form with
a brush, or microtip pen.
TYPES OF CONFORMAL COATING
ACRYLIC
For general use
Mfg. Part No. 419B
Dielectric
strength 1500 V/mil
Hard
finish
Meets
IPC-TM-650 and Meets IPC-CC-830
SILICONE
For high temp. environments
Mfg. Part No. 422
Dielectric
strength 2000 V/mil
Flexible
finish
Meets
IPC-TM-650
URETHANE
For harsh enviroments
Mfg. Part No. 4223
Dielectric
Strength 2000 V/mil
Hard
flexible finish
Harsh
environments
Solvent
and chemically resistant
Fungus
Resistance MIL-V-173C-2
6 to 10"
E-mail
Phone
Fax
salesusa@mgchemicals.com
1-800-201-8822 Ext. 125
1-604-888-3084 Ext. 125
1-800-708-9888
1-604-888-7754
For technical specifications,
MSDS, tech support and more
To customize this AppGuide
for your own use please email
www.mgchemicals.com info@mgchemicals.com
ISO 9001:2000
Registered Quality System. QMI Certificate #004008 Burlington, Canada.
MG Chemicals
AppGuide
One company. Many solutions.
2
Epoxy
Epoxies are two part
encapsulating
compounds. They are
mixed and then poured
onto the circuit board.
Once cured, the result
is extremely hard and
durable. Epoxy is most
effective when board
is cover with at least
¼ inch in thickness.
Epoxies provide
excellent protection against impact, shock, conductivity,
TYPES OF EPOXY
Black Epoxy (Mfg. Part No. 832B)
Black
in color
General
use
Secure
against technology theft
Clear Epoxy (Mfg. Part No. 832C)
Amber
in color
Allows
visual of board after cure
Thermally Conductive (Mfg. Part No. 832TC)
Black
in color
Used
to encapsulate boards with components
that give off heat. Enables heat dissipation.
Flame Retardant Epoxy (Mfg. Part No. 832FRB)
Black
in color
Used
in environments where PCB may be
subject to possible fire hazards
moisture, abuse, chemicals, and analysis. Provides
EPOXY ENCAPSULATED
technology security. Excellent for explosion proof
COMPONENTS ARE
FULLY SUBMERSIBLE
components. Epoxies are extremely difficult to remove.
Potting and
encapsulating
with Epoxies and
RTV Silicones
Part
1
Part
2
Application Instructions
Mix parts 1 and 2 of the RTV Silicone or epoxy in a
seperate container according to the product's mix
ratio. Pour the mixed 2-part encapsulant into the
enclosure, fully covering your circuitboard. Cure
time will vary from product to product, please see
product pages on website for details.
3
RTV Silicone
TYPES OF RTV SILICONE
SILICONES ARE IDEAL
FOR HIGH TEMP.
FLUCTUATIONS
RTV Silicones are Room Temperature Vulcanizing Silicones.
General
Use
Generally, 2-part flowable silicones are used for encapsulating.
Optically
Clear
Thermally
Conductive
They are used in the same fashion as epoxies but is able to be
Extreme
High Temperature
removed when repairs have to be done later. RTV Silicones are
Extreme
Low Temperature
ideal for environments exhibiting high temperature fluctuation.
Flame
Retardant
For specifications on any products in this AppGuide, visit www.mgchemicals.com
E-mail
Phone
Fax
salesusa@mgchemicals.com
1-800-201-8822 Ext. 125
1-604-888-3084 Ext. 125
1-800-708-9888
1-604-888-7754
For technical specifications,
MSDS, tech support and more
To customize this AppGuide
for your own use please email
www.mgchemicals.com info@mgchemicals.com
ISO 9001:2000
Registered Quality System. QMI Certificate #004008 Burlington, Canada.
MEMS传感器
