Die-cut gaskets have served manufacturing for decades, but two liquid-dispensed alternatives — Cured-in-Place Gaskets (CIPG) and Formed-in-Place Gaskets (FIPG) — now handle sealing on everything from engine blocks to EV battery trays. Choosing between them comes down to one question: does the assembly ever need to come back apart?

What Is FIPG?

FIPG dispenses a liquid sealant onto one mating surface, then joins the parts before the sealant cures. The material flows into every scratch and machining mark on the flange before it sets, producing a tight seal that also bonds the two surfaces together. FIPG materials are typically RTV silicones or anaerobic sealants, curing via ambient moisture or, in the anaerobic case, the absence of oxygen between the mated metal surfaces. Because it cures in contact with both sides, FIPG behaves as gasket and adhesive at once — well suited to permanent or rarely disassembled joints.

What Is CIPG?

CIPG takes the opposite sequence: the sealant is dispensed and fully cured — typically by UV light or heat — before the parts are ever joined. The result is a solid elastomeric bead, much like a molded rubber gasket, that seals through compression rather than chemical bonding to the second surface. Because the bead is already solid when parts are mated, assembly can happen immediately or weeks later, and the parts separate cleanly for service.

Key Differences

Assembly timing: FIPG has a limited open time before the sealant skins over; miss it and seal integrity suffers. CIPG removes that pressure entirely — a cured part can be stored or shipped before final assembly.

Serviceability: CIPG is the clear choice when a product needs to be opened for repair, calibration, or maintenance. FIPG bonds both surfaces, so separating them risks warping flanges or cracking housings, and old material must be scraped off before resealing.

Sealing mechanism: FIPG relies on adhesion and displacement — it fills the gap and glues the parts together. CIPG relies on compression and resilience, which makes the elastomer’s compression-set behavior the critical selection criterion.

Production speed: UV-cured CIPG beads can be ready in 5 to 30 seconds, outperforming FIPG’s hours-to-days full-cure window, though FIPG’s immediate assembly can still be a throughput advantage when parts don’t need immediate pressure testing.

Flange tolerance: FIPG is more forgiving of flange imperfections since the wet material spreads during assembly. CIPG needs tighter control of bead height and mating-surface flatness for uniform compression.

Material Considerations

FIPG typically uses RTV silicones, valued for temperature resistance and flexibility, or anaerobic adhesives for rigid metal-to-metal joints like engine blocks and gearbox housings. CIPG relies on UV-curable acrylates and silicones for near-instantaneous high-speed curing, or heat-cure elastomers where UV light can’t reach every part of the bead or specific chemical resistance is required. Email Us if you need help matching a chemistry to a specific oil, coolant, or temperature exposure profile.

Where Each Technology Fits

FIPG remains dominant on oil pans, timing chain covers, valve covers, large gearboxes, hydraulic reservoirs, and water pumps — components rarely opened and needing a high-pressure, permanent bond. CIPG has taken over electronics enclosures, EV battery packs, automotive and architectural lighting, and appliances with components like dispensers or control panels that need periodic servicing.

Weighing the Tradeoffs

FIPG offers superior gap-filling on imperfect flanges, structural bonding, and lower equipment cost since no curing lamps or ovens are required — at the cost of difficult disassembly and open-time management. CIPG offers excellent serviceability, no open-time constraint, and fast UV cure with no squeeze-out contamination risk — at the cost of higher dispensing precision and curing-equipment investment. Automated dispensing is essential either way: consistent bead volume avoids leaks or waste, path accuracy keeps the bead centered on complex 3D flanges, and for CIPG the automation must also integrate the curing cycle, often via a conveyorized UV system with vision-guided path correction.

A Decision Framework

Ask whether the part needs servicing (favors CIPG), whether the assembly is rigid metal or a flexible plastic housing (rigid favors FIPG anaerobics, flexible favors CIPG’s elasticity), what cycle time the line requires (instant UV cure favors CIPG at high volume), what internal pressure the joint must hold (FIPG’s dual-surface bonding generally wins), and what capital budget exists for curing infrastructure (FIPG has the lower entry cost).

For background on the curing equipment side of a CIPG line, see Incure’s guides to UV LED flood lamps and UV cure chambers, and for the adhesive-selection principles that carry over to FIPG anaerobic systems, UV glue vs. epoxy for heavy-duty repairs.

The Future of Liquid Gasketing

Sustainability is pushing both technologies toward low-VOC chemistries and primer-free bonding, while EV battery-tray demand is driving rapid growth in serviceable, high-performance CIPG. Hybrid materials that combine FIPG-level adhesion with CIPG-level cure speed, or dual-cure systems that finish shadowed areas via moisture, are moving from lab to production.

Conclusion

There’s no universal winner between CIPG and FIPG — the right choice depends on your product’s serviceability requirements, pressure demands, and production environment. Incure supplies UV-curable and anaerobic-compatible sealant chemistries for both approaches, and our engineering team can help you validate material selection against your specific flange design and environmental exposure. Contact Our Team to discuss the right liquid gasketing strategy for your assembly.

Visit www.incurelab.com for more information.