HumiSeal - Urethane Conformal Coating | 1A33

HumiSeal® 1A33 conformal coating is:

• Urethane chemistry
• chemically resistant
• single component
• contains no free isocyanates
• used in combination with Thinner 503/521
• MIL-I-46058C qualified
• RoHS directive 2015/863/EU
• Recognized under UL File Number E105698

HumiSeal 1A33 conformal coating has:

• excellent moisture and environmental protection for printed circuit assemblies
• fluorescence under UV light for ease of inspection

Application of 1A33 Conformal Coating

Conformal coatings can be successfully applied to substrates that have been cleaned before coating and substrates assembled with low residue “no-clean” materials. Users should perform adequate testing to confirm compatibility between the conformal coating and their particular assembly materials, process conditions, and cleanliness level. Please contact a HumiSeal representative for additional information.

Dipping
Depending on the complexity, density, and configuration of components on the assembly, it may be necessary to reduce the viscosity of HumiSeal 1A33 with HumiSeal Thinner 503 to obtain a uniform film. Once optimum viscosity is determined, a controlled immersion and withdrawal rate (typically, 5 to 15 cm/min) will further ensure even deposition of the coating and provide a uniform film. During application, evaporation of solvent causes an increase in viscosity that can be adjusted by adding small amounts of HumiSeal® Thinner 503. Viscosity in the dip tank should be checked regularly using a simple measuring device, such as a Zahn or Ford viscosity cup. 

Spraying
HumiSeal 1A33 can be sprayed using conventional spraying equipment. Spraying should be done in an environment with adequate ventilation so that vapor and mist are carried away from the operator. The addition of HumiSeal® Thinner 521 is necessary to ensure a uniform spray pattern resulting in a pinhole-free film. The amount of thinner and spray pressure will depend on the specific type of spray equipment and operator technique. The recommended ratio of HumiSeal 1A33 to HumiSeal Thinner 521 is 1:1 by volume; however, the ratio may need to be adjusted to obtain a uniform coating.

Brushing
HumiSeal 1A33 may be brushed with a small addition of HumiSeal Thinner 503. The uniformity of the film depends on the component density and operator technique.