Types of Aircraft Sealant: Uses, Selection and Buying Guide

The main types of aircraft sealant are fuel tank sealants, corrosion-inhibiting sealants, and silicone sealants used for sealing, gasketing or electrical insulation. These categories describe different jobs, not interchangeable materials: buyers also need the specified part number, application form and packaging to identify the correct product.

Key Takeaways

• Fuel tank sealants are selected for joints and surfaces exposed to aviation fuel.
• Corrosion-inhibiting sealants combine a sealing function with protection at susceptible interfaces.
• Silicone sealants may be specified for gasketing, sealing or electrical insulation, depending on the product.
• Class, part number and package size can distinguish products within the same sealant family.
• A useful RFQ identifies the required material precisely rather than asking for a generic “aircraft sealant.”

Types of Aircraft Sealant by Application

The most useful first question is what the sealant must do. A fuel-wetted joint, a joint between dissimilar metals and a gasket-like seal around a component create different selection requirements. Product descriptions may overlap—for example, a corrosion-inhibiting sealant can also be described as fuel-resistant—but the intended maintenance application remains the starting point.

These are functional categories, not a complete classification system. A product’s chemistry, application characteristics and exact identifier narrow the choice further. For example, the listed P/S 890 Class A and PR1776MB-2 products are both described as fuel tank sealants, but they have different part numbers and descriptions; a purchase request should not treat them as the same item.

Fuel Tank and Corrosion-Inhibiting Sealants

Fuel tank sealants are associated with fuel-wetted areas and the joints that must retain fuel. The listed PS890A-2 fuel tank sealant is described as P/S 890 Class A for integral fuel tanks. The separate PR1776MB2 listing describes a two-part sealant for fuel-tight sealing at critical fuselage and integral fuel tank joints. Their shared application category does not make their identifiers interchangeable.

Corrosion-inhibiting sealants address a different concern: protecting a sealed interface where corrosion is a consideration. The listed PS870B-2 corrosion-inhibiting sealant is offered in a 100 mL Semkit. Another listed product, PS870B-1/2, is described as P/S 870 Class B for aluminum alloys and dissimilar metals. The listings use different part numbers, so a buyer should preserve the exact identifier provided in the maintenance or purchasing requirement.

When screening these types, describe both the location and the purpose of the seal. “Fuel tank joint” communicates a different need from “sealed interface requiring corrosion protection,” even if both locations are on the same aircraft. That distinction helps the engineering and procurement teams focus on the relevant product family before comparing individual listings.

Silicone Sealants, Adhesive Sealants and Coatings

Silicone identifies a material family, not a single aircraft use. The listed Momentive RTV157 silicone sealant is described for sealing, gasketing and electrical insulation. The RTV106 listing likewise identifies sealing, gasketing and electrical insulation, with high-temperature sealing among its stated uses. If an item is specified as a silicone adhesive sealant, its identifier still matters: the RTV159 listing describes a one-component product under that name.

Some silicone materials have more than one described application form. Dapco 18-4F is described as a two-component silicone paste used as a coating, sealant or filleting material. In this context, a coating covers a surface, while a fillet is material placed along an edge or joint. Those descriptions help a buyer understand the requested form of work, but they do not identify a substitute for a specified part number.

For a silicone request, record whether the requirement calls for a sealant, adhesive sealant, coating or filleting material. Then retain the exact product designation. “Silicone” alone leaves open questions about the product and the work it is intended to perform.

How Form, Class and Packaging Affect an RFQ

Two requests can name the same general type of sealant yet describe different items. Class designations, component format and package size can all be relevant to identifying what purchasing needs to obtain. They should be copied accurately from the requirement rather than inferred from the application.

• Part number: Use the complete identifier, including its suffix, such as PS890A-2 rather than “P/S 890.”
• Class or product description: Include it when supplied; the PS890A-2 listing identifies P/S 890 Class A.
• Component format: Note a specified one- or two-component product. The listed RTV159 is one-component, while Dapco 18-4F is two-component.
• Package: State an identified package requirement, such as the 100 mL Semkit described for PS870B-2.
• Quantity and use: Give the requested quantity and a concise application description so the quotation can be matched to the request.

For example, a buyer could write: “Please quote PPG PS870B-2 corrosion-inhibiting sealant, 100 mL Semkit, quantity 12, for an aircraft maintenance requirement. Identify the product and packaging on the quote.” This is more actionable than “quote corrosion sealant” because it supplies the listed part number and package without assuming that another corrosion-inhibiting product is equivalent.

Selection and Handling Questions to Resolve

Before ordering, separate questions about the job from questions about the material. What surface or joint is being sealed? Is fuel exposure, corrosion protection, gasketing or electrical insulation the stated purpose? Does the requirement specify a class, application form or package? Answers to those questions help prevent a broad category name from obscuring the actual purchasing requirement.

For planning, teams may also need to confirm the current product data sheet, the condition of the supplied material and any handling information required for their process. These are practical questions to raise when identifying an item; they are not properties that can be assumed from a product family name.

Maintenance caution: Follow the applicable aircraft maintenance documentation and the manufacturer’s current data sheet for selection, preparation, application and handling; verify any required approvals and airworthiness considerations before using a material on an aircraft.

Sourcing from CraftJetAero

Buyers can review the broader aviation chemicals category and request a quote from CraftJetAero by part number. Include the specified package, quantity and any identifying details from the purchase requirement.

Frequently Asked Questions

What are the main types of aircraft sealant?

Common functional categories include fuel tank, corrosion-inhibiting and silicone sealants. Silicone products can be described more specifically by use, such as gasketing, electrical insulation or adhesive sealing.

Is a fuel tank sealant the same as a corrosion-inhibiting sealant?

No. The names emphasize different primary functions: sealing fuel-exposed areas versus sealing while addressing corrosion at an interface. A particular product description may mention more than one property, so identify the required item by its full designation.

What does RTV mean in a silicone sealant name?

RTV stands for room-temperature vulcanizing. It describes a curing category; by itself, it does not identify a particular product or aircraft application.

Can two products in the same sealant category be substituted?

Being in the same category does not establish equivalence. Different part numbers can represent different products, forms or intended applications.

What should an MRO buyer include in a sealant quote request?

Include the complete part number, specified class or description, package, quantity and relevant application context. An exact identifier is more useful than a general request for “aircraft sealant.”