• HumiSeal 1A33 Urethane Conformal Coating is a one component, polyurethane coating that is used for circuit board applications. It contains no free isocyanates and fluoresces under UV light to aid inspection. It can be applied by spraying, brushing, or dipping methods. 1 L Can.
• Well suited for general printed circuit board applications.

HumiSeal 1A33 coating is MIL-I-46058C qualified, IPC-CC-830 and RoHS Directive 2002/95/EC compliant and recognized under UL File Number E105698.
Cleanliness of the substrate is of extreme importance for the successful application of a conformal coating. Surfaces must be free of moisture, dirt, wax, grease, flux residues and all other contaminants. Contamination under the coating could cause problems that may lead to assembly failures.

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 in order to obtain a uniform film. Once optimum viscosity is determined, a controlled rate of immersion and withdrawal (5-15 cm/min) will further ensure even deposition of the coating and ultimately a uniform film. During the application, evaporation of solvent causes an increase in viscosity that should 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 the vapour and mist are carried away from the operator. The addition of HumiSeal Thinner 521 is necessary to ensure a uniform spray pattern resulting in pinhole-free film. The amount of thinner and spray pressure will depend on the specific type of spray equipment used 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 applied by brush. Uniformity of the film depends on component density and operator's technique.