Formed-in-place gaskets (FIPG) deliver design flexibility and repeatable sealing, but the process is unforgiving of poor setup. Most FIPG defects trace back to a handful of root causes in surface preparation, curing, or dispensing. Knowing those causes is the first step to consistent, leak-free results. Poor Adhesion and Delamination When the bead peels away from the flange, a leak path opens even though the gasket itself is intact. Contamination is the usual reason. Oils, grease, mold release, machining fluid, and even fingerprints leave a film that blocks adhesion. Low substrate surface energy, an incompatible pairing of sealant chemistry and flange material, and undercure all weaken the bond as well. The remedy is a validated cleaning step, typically a solvent wipe or plasma treatment, confirmed on production parts with a peel test. Where the flange is a low-surface-energy plastic, a primer restores adhesion. Confirm the sealant is rated for the substrate material before committing the line. Incomplete Cure and Soft Spots Sections of the bead that stay tacky or gel-soft compress permanently under clamp load and lose sealing force. The cause is almost always insufficient cure energy: too little oven time for heat cure, too little UV dose for light cure, or too little ambient moisture for RTV. Off-ratio mixing in two-part systems and UV shadowing behind ribs or bosses produce the same result locally. Measure the actual cure conditions rather than assuming them. For UV systems, a radiometer confirms dose at the bead, and a dual-cure sealant handles shadowed geometry. Matching lamp output to the material is covered in our guide to selecting a UV lamp for resin and sealant curing. For heat cure, profile the oven with the part loaded rather than empty. Dispensing Inconsistency A bead that varies in width or height, skips, contains voids, or lays down too much material points to the dispensing hardware. Worn nozzles, incorrect pressure, and pump wear all shift flow. Sealant viscosity drifts with temperature and with settling in the reservoir, while robot path errors and entrapped air introduce gaps. Put the dispensing equipment on a preventive maintenance schedule that includes nozzle replacement, temperature-condition the sealant so viscosity stays stable, and switch to a de-aired cartridge where air entrainment causes voids. Compression Set If the cured gasket stops rebounding after sustained clamp load, sealing force decays and the joint eventually weeps. This happens when the material has poor compression-set resistance at its service temperature, when assembly applies excessive clamp force, or when the gasket is exposed to chemicals and heat beyond its rating. Select a sealant with a documented low compression set at the operating temperature, design the flange with a hard stop or bead-height control so assembly cannot over-compress the gasket, and verify compatibility with any fluid the joint contacts. Material Bleed-Out and Migration Uncured sealant that flows past the intended sealing zone before it gels can contaminate nearby surfaces or electrical contacts. The drivers are viscosity too low for the dispensing speed, excess pressure or an oversized nozzle, and surface…

A formed-in-place gasket, or FIPG, is a liquid or paste sealant dispensed directly onto a component and cured in position to create a custom-fit seal. Unlike a die-cut gasket made separately and installed by hand, an FIPG becomes an integral part of the assembly, which changes how engineers approach sealing. Defining the Formed-in-Place Gasket An FIPG starts as a flowable material, most often a silicone, polyurethane, or acrylic, that is applied in a precise bead along a sealing surface and then cured. The bead follows the exact geometry the joint requires, so the seal matches the part rather than the part being designed around a standard gasket profile. Dispensing is usually automated. A robotic or XY-gantry system applies a repeatable bead volume and path, which controls the two variables that matter most for seal quality: where the material sits and how much of it there is. How the FIPG Process Works Most FIPG lines run in three stages: Dispensing. An automated system lays a bead of sealant onto the flange or groove. Bead width and height are set by nozzle size, flow rate, and traverse speed. Mating. In compression FIPG (also called cure-in-place), the second part is assembled onto the wet bead, which spreads the material and fills surface irregularities. In true form-in-place designs, the bead is cured before assembly and acts as a resilient gasket on its own. Curing. The material solidifies by one of several mechanisms: Room-temperature vulcanizing (RTV), driven by ambient moisture. Heat curing in an oven, which shortens cycle time. UV curing, which fixes the bead in seconds and suits high-speed lines. Matching lamp output to the sealant is covered in our guide to choosing a UV lamp for resin and sealant curing. Dual cure, combining UV with a moisture or heat secondary mechanism so shadowed sections still harden. Once cured, the bead forms a continuous barrier against fluids, gases, dust, and airborne contaminants. Why Manufacturers Use FIPG The shift toward FIPG in electronics, powertrain, lighting, and enclosure manufacturing reflects several practical gains: Design freedom. The bead can follow complex, multi-level, or tightly spaced flange geometry that a cut gasket cannot cover economically. A compact hydraulic manifold with internal channels can be sealed along routes that would be impossible to tool as a discrete part. Fewer leak paths. A seamless bead adhered to the substrate removes the seams, joints, and compression-set behavior that let pre-cut gaskets leak over time. Lower inventory and labor. One cartridge or drum of sealant replaces a family of gasket part numbers, and automated dispensing removes manual placement and the errors that come with it. Less waste. FIPG is additive, so material is placed only where it is needed rather than die-cut from sheet stock with the offcuts scrapped. Tailored durability. Formulations can be selected for chemical exposure, thermal range, or vibration, extending the service life of the sealed assembly. Three Related Approaches FIPG is one of a family of dispensed-seal methods, and the terms are often confused. In a true formed-in-place…

Sealing choices look small on a bill of materials and large on a warranty report. Deciding between a pre-cut gasket and a formed-in-place liquid gasket shapes tooling cost, assembly labor, inventory, and how long the joint stays leak-free in service. Conventional Pre-Cut Gaskets For decades, die-cut or molded gaskets from rubber, cork, fiber, or polymer sheet have been the default. They sit between two mating faces and seal under bolt compression. Where they still make sense: Well-characterized materials with published chemical and temperature ratings. Low production volumes where manual placement is quick. Applications an OEM specifies by part number for warranty reasons. Very large flange gaps that a liquid bead cannot bridge. Their limits: Tooling. Each shape needs its own die, adding upfront cost and lead time. Compression set. Over months under load the material loses rebound and the seal relaxes. Handling. Misalignment or a small tear during assembly opens a leak path. Inventory. Every size and shape is a separate stocked item. Scrap. Die-cutting wastes a meaningful fraction of the sheet. Formed-in-Place Liquid Gaskets A formed-in-place gasket, also called FIPG or dispense-in-place, is a liquid or paste bead applied directly to the flange that then cures into a seamless custom seal. The process suits robotic dispensing for precision and speed. Where FIPG is strong: Geometry. The bead follows any contour, corner, or multi-level surface, and seals around internal partitions in one continuous pass. Surface conformity. The uncured material flows into machining marks and minor scratches, closing leak paths a rigid gasket bridges over. No compression set. The cured bead does not relax the way a compressed sheet does, and it resists vibration and thermal cycling. Inventory and scrap. One cartridge replaces a family of pre-cut shapes, and material is placed only where needed. Automation. A dispensing robot lays a repeatable bead at line speed. What it demands: Cure time. Handling strength comes in minutes, but full cure can take hours before the joint sees pressure or fluid. Surface prep. Faces must be clean, dry, and free of oil for the bead to adhere and cure. Bead control. Too much material squeezes out into internal passages; too little leaves gaps. Automated dispensing makes this repeatable. Chemistry match. Silicone, anaerobic, and polyurethane FIPG each fit different temperature, chemical, and gap conditions. Choosing Between Them FIPG tends to win when flanges are irregular or hard to machine flat, when the joint sees high vibration or thermal cycling, for fluid containment such as covers and housings, for complex geometries, and for automated high-volume assembly. Pre-cut gaskets hold their place for safety-critical high-pressure joints with specific multi-layer construction, for very large gaps, when rapid repeated disassembly is routine, and when an OEM mandates a part. Differential expansion between a cover and its housing is a common driver of seal fatigue. Our guide on how CTE mismatch causes adhesive bond failure covers the mechanism, which applies to cured sealant beads as well as adhesives. Email Us with your flange material, operating temperature and pressure, fluid…