Polysulfide
Frequently Asked Questions (FAQ)
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What are polysulfide sealants?
Polysulfide sealants are elastomeric sealing materials used in applications that require flexibility, adhesion, and resistance to certain fluids. In aerospace, they are commonly used for fuel tank sealing, fuselage sealing, access doors, aerodynamic smoothing, windows, canopies, and other aircraft sealing applications.
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Why are polysulfide sealants used in aerospace applications?
Polysulfide sealants are used in aerospace because they offer a combination of flexibility, adhesion to common aircraft substrates, and resistance to aviation fuels, hydraulic fluids, oils, and water. These properties make them useful for sealing areas exposed to vibration, movement, temperature change, and fluid contact.
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Why are polysulfide sealants commonly used for fuel tank sealing?
Aircraft fuel tank applications require sealants that can help support fuel containment and resist exposure to aviation fuels. Polysulfide sealants are widely used in this area because they provide fuel resistance, adhesion, and cured flexibility. Product selection should be based on the aircraft specification, substrate, application method, and service requirements.
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What are common aerospace applications for polysulfide sealants?
Common aerospace applications include integral fuel tank sealing, cabin and fuselage sealing, windshield sealing, aerodynamic smoothing, access door sealing, corrosion protection, windows and canopies, and selected electrically or thermally conductive applications.
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What aircraft substrates are commonly associated with polysulfide sealants?
Polysulfide sealants are commonly used with aircraft substrates such as aluminium, stainless steel, and composites. Surface preparation, product selection, and application conditions are important factors in final performance.
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Are polysulfide sealants flexible after cure?
Yes. Cured polysulfide sealants are valued for flexibility, tensile properties, and elongation. This flexibility can help accommodate vibration, joint movement, and impact that may occur during aircraft operation.
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Are polysulfide sealants resistant to aviation fluids?
Polysulfide sealants are known for resistance to aviation fuels, hydraulic fluids, oils, and water. The level of resistance depends on the specific product, cure condition, exposure environment, and application requirements.
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What temperature range is associated with polysulfide sealants?
Temperatures range from -60°F to 250°F (-51°C to 121°C). Temperature performance should always be confirmed against the applicable product technical data sheet and end-use conditions.
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Can polysulfide sealants be used for cabin and fuselage sealing?
Yes. Polysulfide sealants are used for general fuselage sealing and cabin pressurization applications, including areas such as gaps between floor panels. The appropriate sealant should be selected based on the aircraft design, specification, and performance requirements.
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Can polysulfide sealants be sanded and painted?
Some polysulfide sealants can be sanded and painted. Compatibility depends on the specific sealant, cure state, surface preparation, paint system, and application process. Users should confirm compatibility before production use.
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How are polysulfide sealants applied?
Depending on the formulation and application, polysulfide sealants may be applied by brushing, trowelling, extrusion, roller application, or other approved methods. Meter-mix and pre-mixed packaging may also be available for selected products.
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Are lightweight polysulfide sealants available?
Yes. H.B. Fuller’s aerospace sealant portfolio includes lightweight polysulfide options for selected applications. Lightweight formulations may support weight reduction goals when they meet the required specification and performance criteria.
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Are rapid-cure polysulfide sealants available?
Yes. H.B. Fuller offers rapid-cure sealant options within its aerospace portfolio. Cure speed varies by product, class, work life, application conditions, and required performance profile.
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What should be considered when selecting a polysulfide sealant?
Important considerations include the application area, substrate, fluid exposure, temperature range, work life, cure profile, application method, specification requirements, and required approvals or qualifications. The selected product should be tested and validated for the intended use.
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Why choose H.B. Fuller for aerospace polysulfide sealants?
H.B. Fuller offers a diverse aerospace sealant portfolio that includes conventional and advanced technologies, lightweight options, rapid-cure options, and products with military and commercial qualifications. H.B. Fuller also provides technical support to help customers evaluate products for specific aerospace applications.
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Are polysulfide sealants suitable for every aerospace sealing application?
No single sealant is suitable for every application. Polysulfide sealants are often selected for fuel resistance, flexibility, and adhesion, but users should review the applicable product data, specifications, processing requirements, and performance expectations before selecting a sealant.
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How can I confirm whether a polysulfide sealant is right for my application?
Review the product technical data sheet, applicable specifications, substrate requirements, and processing guidance, and reach out to H.B. Fuller for further guidance and testing. Nothing beats sample trials to confirm different applications, and our team of technical experts at H.B. Fuller is ready to assist your team and determine whether a product is suitable for the intended application, process, and end-use conditions.