CarPro FlyBy Forte V4 Glass Coating

No — they are different chemistries from the same brand. FlyBy30 uses heptadecafluorodecyl-trimethoxysilane (a long-chain perfluoroalkylsilane PFAS, CAS 83048-65-1) at 1–5% in an ethanol carrier and is rated for roughly 6–12 months on a daily driver. FlyBy Forte uses hexadecyltrimethoxysilane plus 3-trimethoxysilylpropane-1-thiol as the silane actives at 1–3% each, dissolved in 2,2,3,3-tetrafluoropropan-1-ol (a fluorinated alcohol carrier) at 80–85%, and is rated for up to 2 years with community data confirming 12–18 months on daily drivers. Forte is the longer-life product but is sold as a multi-step kit with mandatory polish and prep steps.

Yes, by definition — but not the same kind as FlyBy30. The carrier solvent at 80–85% is 2,2,3,3-tetrafluoropropan-1-ol, which contains a –CF2–CF2– backbone. Under the OECD 2021 PFAS structural definition (any substance containing at least one fully fluorinated methyl or methylene carbon atom), this qualifies as PFAS. It is a short-chain volatile fluorinated solvent that evaporates during cure, materially milder in persistence and bioaccumulation than the long-chain perfluoroalkyl chains in classical fluoroalkylsilane coatings. The silane actives left on the glass are non-fluorinated alkylsilane and mercaptosilane chemistry. The CarCareTruth environment score reflects the PFAS classification with a hard cap at 3 — the cap is categorical regardless of the chain-length difference.

Because the SDS Section 2 mixture-level classification carries H332 (acute inhalation toxicity Category 4 — 'harmful if inhaled'), driven by the high-concentration tetrafluoropropanol carrier (vapor ATE 11 mg/L per SDS Section 3). H332 is a real GHS classification on the inhalation pathway, not generic boilerplate language. SDS Section 8 specifies a P1–P3 particulate filter when ventilation is insufficient. For normal outdoor application or a garage with the door open, vapor disperses quickly enough that a respirator is not required, but applying in a closed garage during prolonged use crosses the threshold where one would be reasonable.

Mandatory for the coating to bond properly. The Ceriglass glass polish removes microscopic glass defects and any old water-spot etching that would otherwise prevent the silane network from anchoring; Eraser is an IPA-style prep wipe that strips residual polish oils before coating. Community reports of premature failure on FlyBy Forte trace almost exclusively to skipped or incomplete polishing and prep — not to the coating chemistry. The kit price reflects this; CarPro sells Forte specifically as a complete-prep system rather than as a standalone bottle.

Community data on r/AutoDetailing and Detailing World forums puts FlyBy Forte at 12–18 months on a daily driver washed regularly, with reports past 18 months on lightly-driven or garaged vehicles. That is close to the label's 'up to 2 years' claim, within the community-confirmed-range tolerance the rubric uses. Gtechniq G1 (non-PFAS alkoxysilane, DANGER signal word from high IPA) is the closest direct competitor and reports a similar 12–18 month range — the difference is chemistry: G1 trades PFAS for a high-IPA solvent system.

Generally no. The silane chemistry needs to bond directly to the silica surface of clean glass; any residual coating, wax, silicone topical repellent (Rain-X), or glass cleaner residue will block adhesion and cause premature failure. The Ceriglass polish included in the Forte kit handles this — it abrades through old coating residues mechanically. If your windshield has an old chemically-bonded coating, the polish step is required, not optional.