Why You Should Use Textron Aviation U470526 B 1/2 Sealant for Aerospace
Aircraft sealants are essential additives for aircraft maintenance. Sometimes, one type of sealant performs more than one duty: sealants like B ½ are used for aerodynamic sealing on panels, windscreens, windows, and other assorted fairings. They are also used for sealing fuel systems (in certain applications).
Textron Aviation is a leading manufacturer of the common B1/2 sealant used in the aviation and aerospace industry. Greenwood Aerospace is a proud distributor of B 1/2 to military and federal buyers!
B 1/2 Sealant Overview
Aviation-grade B 1/2 sealant is a specialized sealant with excellent anti-oil and anti-fuel properties. It is a two-part polysulfide compound used widely in the aircraft industry, primarily for sealing fuel tanks, windshields, windows, and fuselage joints.
Sealants are made to keep liquids in or out, depending on the application. They also have to resist chemicals to prevent corrosion.
B 1/2 is one of the traditional sealants used all over the aircraft and is a staple in the expendables supply points at all military aircraft maintenance facilities. It is a two-part, chemically curing polysulfide compound that, once applied, forms a rubbery seal that bonds extremely well to common aircraft substrates that include aluminum, stainless steel, titanium, and composites. It is a mixed compound that requires a prescribed mixing period, and technicians must spend approximately 30 minutes setting it up before it cures. Hence the “½” in the name.
Aerospace Sealant Benefits
Choosing aircraft and aerospace sealants is essential for all maintenance shops, especially for airframe components. It is more than finding a product that sticks; it has to work with dissimilar metals, have adequate bond strength, and resist petroleum products if it is meant to contain them.
Here are the reasons why Textron’s U470528 B 1/2 stands out in a crowd:
- Chemical resistance: B 1/2 was designed to be fuel resistant for Jet A, JP-8, aviation oils, hydraulic fluids that include MIL-PRF-83282 and MIL-PRF-5606, and Skydrol®.
- Flexibility: B 1/2 maintains high flexibility over time and across temperature ranges to prevent cracking or peeling under vibration and/or pressure fluctuations.
- Low Shrinkage: B 1/2 holds its volume while it cures, and gives a uniform seal even in thin bond lines, which are common on some windows and panels.
- Long Service Life: B 1/2 is resistant to ozone, UV radiation, and thermal cycling. It will last for extended periods between maintenance intervals.
- Easy Application: take it from a former technician: it does not get much easier than B 1/2. Press the plunger to mix it, and then apply. It applies easily to curved and uneven surfaces, leaving a clean, smooth surface.
Compared to Other Sealants
Suppose you compare B 1/2 sealant to silicone or polyurethane sealants—polysulfide-based sealants like B 1/2 offer superior chemical resistance and longer lifecycles in fuel-exposed areas. Silicone sealants do cure faster and offer higher elasticity, but they will fail due to poor fuel and chemical resistance on faying surfaces.
Polyurethanes do well in exterior applications but are sensitive to moisture during the cure process. This often leads to bubbling or otherwise compromised adhesion in high-humidity environments. Textron’s U470528 B 1/2 provides a better overall long-term performance profile for structural and fuel-containment sealing.
Class B Sealant Specifications
Class B sealants have strong anti-sag properties and are regularly used for fillet sealing, fay sealing, and other applications that need precise application. B 1/2 sealant can be applied using several different methods. It can be applied straight from the tube, from an extrusion gun, or even with spatulas. It is designed to hold in place during cure without running or dripping. It is a very thick, exceptionally sticky sealant, so running or dripping is unlikely.
Textron’s U470528 B ½ sealant meets AMS-S-8802 and MIL-PRF-81753 specifications, making it compatible with most aviation-grade materials and suitable for use on most airframes.
B 1/2 Sealant Uses
B 1/2 sealant is a proper multi-purpose sealant, often used for the following purposes:
- Fuel tanks: it prevents leaks and corrosion in integral fuel tanks.
- Fuselage and fairing joints: B 1/2 acts as a barrier to prevent moisture ingress and drag reduction at joints in the aircraft skin.
- Windshields and windows: B 1/2 is the industry standard sealant to seal windows, windscreens, and windshields to maintain pressurization and prevent water intrusion.
- Avionics bays: B 1/2 protects electronics from exposure to moisture, chemicals, and even fuel vapors.
Sealant Selection Tips
Remember the following for sealant selection because choosing the right sealant matters.
First, always check MIL-SPEC or AMS compliance. B 1/2 is commonly used for applications that call for a MIL-PRF-81733-compliant sealant.
Also, match the application life. The 30-minute application life of B 1/2 is perfect for jobs requiring careful tooling without long wait times.
Consider the environmental considerations of the primary operating base. For exterior applications in direct sunlight and temperature extremes, always verify the sealant's UV and thermal resistance.
B 1/2 does need to be stored appropriately, usually in a HAZMAT locker kept at room temperature. Follow the manufacturer’s guidelines about temperature and packaging.
Finally, get your stock of B 1/2 from an authorized distributor. Greenwood Aerospace is your preferred partner for B 1/2 procurement and hundreds of other common lubricants, sealants, and solvents. We also specialize in procuring all kinds of aircraft parts and components.
If you need to stock your lockers with B ½ sealant, reach out to Greenwood Aerospace at gsasales@greenwood.aero or give us a call at 580-865-6000 or 833-GSA-EBUY (833-472-3289). As a proud Native American-owned, HUBZone-certified small business, we are committed to delivering high-quality service with rapid, reliable delivery.
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