Aerosol 1A27
Model No: 1A27

HumiSeal® 1A27 Aerosol is a fast drying, clear urethane conformal coating intended for use on printed circuit assemblies. The product is conveniently dispensed from aerosol cans, utilizing an environmentally safe, non-ODP propellant. The coating may be removed chemically using HumiSeal® Stripper 1063.

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Application of HumiSeal® 1A27 Aerosol

  • Allow 48 hours minimum to reach room temperature before using cans stored or received during cold weather.
  • When applied in conditions of high ambient humidity, blushing (cloudy white film) may appear.  Heating the coated assembly in an oven for 1/2 hour at 76°C eliminates this condition.
  • Cleanliness of the substrate is extremely important to the successful application of a conformal coating.  Surfaces should be free of moisture, dirt, wax, grease and all other contaminants.  Otherwise, ionic or organic residues on the substrate could be trapped under the coating and cause problems with adhesion or electrical properties.  The highest long term reliability for a coated printed circuit assembly will be when the conformal coating is applied over a clean, dry substrate.**
  • Mask areas not requiring coating from overspray using suitable non-silicone masking methods or materials.
  • Shake can vigorously before using and repeat frequently during use.
  • Best results are obtained by spraying from a distance of 30 – 40cm in light even coats. A film thickness of 25 – 75 microns is sufficient to provide protection.
  • To clean nozzle after use, hold can upside down, then press nozzle for a few seconds.

**The application of conformal coatings over no clean flux is a common practice. The user should perform adequate testing to confirm compatibility between the conformal coating and their particular assembly materials and process conditions. 


Properties of Humiseal® 1A27 Aerosol

Solids Content, % by weight per Fed-Std-141, Meth. 4044

6.1 ± 1 %


475 grams/liter

Recommended Coating Thickness

25 – 75 microns

Drying Time to Handle per Fed-Std-141, Meth. 4061

15 minutes

Time Required to Reach Optimum Properties

30 days at RT, 30 hours @ 76°C, 20 hours @ 88°C

Shelf Life, DOM

24 months

Thermal Shock, 50 cycles per MIL-I-46058C

-65° to 125°C

Coefficient of Thermal Expansion – TMA

170 ppm/°C

Glass Transition Temperature – DSC


Modulus – DMA

18.1 MPa

Dielectric Withstand Voltage, per MIL-I-46058C

>1500 volts

Dielectric Breakdown Voltage, per ASTM D149

7500 volts

Dielectric Constant, at 1MHz and 25°C per ASTM D150-98


Dissipation Factor, at 1MHz and 25°C per ASTM D150-98


Insulation Resistance, per MIL-I-46058C

2.0 x 1014 ohms(200TΩ)

Moisture Insulation Resistance, per MIL-I-46058C

1.2 x 1010 ohms (12GΩ)

Recommended Stripper

HumiSeal® Stripper 1063