FAQs
What is DOWSIL Q4-2805 used for?
It is a one-part fluorosilicone channel sealant used primarily as a groove-injection sealant for aircraft fuel tanks. Its fuel and oil resistance and non-curing nature make it suitable for sealing applications exposed to fuels and vapors, where a reworkable, no-cure sealant is needed rather than one that sets hard.
Why is fluorosilicone used instead of standard silicone?
Fluorosilicone resists fuels and oils far better than standard silicone, which can swell or degrade on contact with hydrocarbons. That resistance gives Q4-2805 superior sealing performance in fuel-system environments, and distributor data indicates it withstands fuel immersion and vapor exposure at temperatures up to +200°C.
What does 'non-curing' mean for this sealant?
Q4-2805 contains no catalyst or curing agent and does not cure to a hard solid, so it stays workable. It can be injected and later reinjected into channels, which suits applications that specifically call for a no-cure sealant that can be reworked or topped up rather than permanently set.
How should it be injected into a channel?
Dow's guidance notes the sealant should not be injected beyond the next port, because back pressure builds up and forcing it further along a channel takes disproportionately longer. Following the recommended port-by-port method helps achieve a proper seal. Always consult the technical data sheet for the correct procedure.
Is any special certification needed for aerospace use?
The product is used in aircraft fuel tanks, and some distributors note that specific Manufacturer Part Numbers tie to particular OEM specifications. Standard manufacturer certification is not always available by default, so aerospace users should confirm the exact specification and documentation their program requires before purchase.
