Sealants, CIPG & FIPG
Polyurethanes & Silicones
Gasketing Sealants (CIPG & FIPG)
Cure-in-place gaskets (CIPG) and form-in-place gaskets (FIPG) are liquid or semi-liquid sealants dispensed directly onto a component and cured to form a custom gasket in place, rather than a pre-cut, preformed gasket installed between mating surfaces. Because the material conforms to the exact geometry of the part as it cures, these systems create a seamless, precisely fitted seal on irregular or complex surfaces where a stamped gasket would be difficult or costly to manufacture.
Polyurethane and silicone are the most common chemistries used for gasketing sealants, each suited to different performance requirements. Polyurethane systems offer strong adhesion and elongation with good chemical resistance to oils and dilute acids or bases. Silicone systems offer a broad service temperature range, excellent weathering and vibration resistance, and gap-filling capability without requiring a primer. Selection depends on the substrate, expected chemical exposure, service temperature, and whether the application calls for cure-in-place assembly or in-line automated dispensing.
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ABchimie R3231 1-Part Neutral Cure Sealant
- Meets MIL-A-46146B requirements
- UL94 V-1 compliant
- Non-corrosive, neutral alkoxy cure
- 8 weeks
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DOWSIL™ 7091 Adhesive Sealant
- Non-sag rheology
- One-part moisture cure
- Stable and flexible from -40 to 180℃
- 5 weeks
Product Selector Guide
Gasketing Sealants (CIPG & FIPG)
| Product | Chemistry / System | Gasket Type | Curing Mechanism | Viscosity / Consistency | Temperature Resistance [°C] | Typical Application | Product Features |
|---|---|---|---|---|---|---|---|
| ABchimie R3231 1-Part Neutral Cure Sealant | Silicone | FIPG | Moisture / alkoxy cure | Paste | -50 to 200 | Industrial / electronics flange sealing | Non-corrosive; MIL-A-46146B; UL94 V-1 |
| DOWSIL 3-8209 | Silicone foam | CIPG | 2-part cure | Foam | — | Electronics / enclosure gasketing | Dispensable silicone foam gasket |
| DOWSIL 3-8235 | Silicone foam | CIPG | 2-part cure | Foam | — | Electronics / enclosure gasketing | Dispensable silicone foam gasket |
| DOWSIL 3-8259 RF Silicone Foam | Silicone foam | CIPG | 2-part room-temperature cure | Reduced-flow foam | — | Automated enclosure gasketing | Fast cure; reduced-flow rheology |
| DOWSIL 7091 Adhesive Sealant | Silicone | FIPG | 1-part moisture cure | Non-sag paste | -40 to 180 | Flanges, housings, general assembly | Strong green strength; flexible seal |
| LAIRD SNL60RXP | Conductive silicone | FIP EMI gasket | Room-temperature moisture cure | Dispensable paste | -50 to 125 | EMI shielding / grounding gaskets | >100 dB shielding; 1-hour handling time |
| LOCTITE 509 | Methacrylate acrylic | FIPG | Anaerobic cure | Paste | — | Rigid metal flanges | Immediate low-pressure sealing |
| LOCTITE 5127 | Acrylic | FIPG | Anaerobic cure | Paste | — | Pumps, housings, gear cases | Tough, resilient and solvent-resistant seal |
| LOCTITE 5156 | Anaerobic acrylic | FIPG | Anaerobic cure | Paste | — | Rigid metal flanges / threaded joints | 2-in-1 flange and thread sealing |
| LOCTITE 518 | Methacrylate acrylic | FIPG | Anaerobic cure | Gel / paste | -55 to 150 | Rigid metal flanges | General-purpose semi-flexible flange sealant |
| LOCTITE 5182 | Methacrylate acrylic | FIPG | Anaerobic cure | Gel | — | Metal housings, cases and covers | Fast cure; medium strength |
| LOCTITE 5188 | Methacrylate acrylic | FIPG | Anaerobic cure | High-viscosity paste | -55 to 150 | Rigid metal flanges | Highly flexible; oil and chemical resistant |
| LOCTITE 5203 | Methacrylate acrylic | FIPG | Anaerobic cure | Thixotropic paste | — | Machined rigid metal flanges | Low strength; easy disassembly; UV fluorescent |
| LOCTITE 5810F | Polyacrylate | FIPG | 1-part moisture cure | Black thixotropic paste | -40 to 150 | Engine, transmission and axle flanges | Non-silicone; UV fluorescent; long open time |
| LOCTITE AA 5810 | Polyacrylate | FIPG | 1-part moisture cure | Heavy-bodied paste | -40 to 150 | Powertrain flange sealing | Non-silicone; strong oil resistance |
| LOCTITE MR 5009 Hi-Tack Gasket Sealant | Resin / solvent-based | Gasket dressing | Solvent evaporation | Liquid | Up to 260 | Pre-cut gasket positioning / sealing | Fast-setting high-tack film |
| LOCTITE MR 5922 | Resin / solvent-based | Gasket dressing | Solvent evaporation | High-viscosity paste | — | Pre-cut gaskets / non-rigid flanges | Slow-drying; remains pliable |
| LOCTITE SI 5015 | Silicone | FIPG | RTV moisture cure | Paste | — | Flexible flange sealing | Tough, flexible silicone rubber |
| LOCTITE SI 5050 | Silicone | CIPG / FIPG | RTV / specialty cure | Paste | — | Industrial gasketing | Silicone gasketing grade |
| LOCTITE SI 5699 | Silicone | FIPG | RTV moisture cure | Paste | — | Rigid flange sealing | Non-corrosive; chemical resistant |
| LOCTITE SI 5900 | Silicone | FIPG | RTV moisture cure | Thixotropic paste | — | Engine oil pans / flexible flanges | High movement and engine-oil resistance |
| LOCTITE SI 5901 | Silicone | FIPG | RTV moisture cure | Paste | — | Automotive / industrial flanges | Flexible RTV gasketing |
| LOCTITE SI 5905 | Silicone | FIPG / CIPG | RTV moisture cure | Black thixotropic paste | — | Engine covers and oil sumps | Excellent bead profile; engine-fluid resistance |
| LOCTITE SI 5910 | Silicone | FIPG | RTV moisture cure | Thixotropic paste | — | Flexible flange sealing | High movement; engine-oil resistance |
| LOCTITE SI 5920 | Silicone | FIPG | RTV moisture cure | Copper-colored paste | High-temperature | High-temperature flange sealing | Non-corrosive; high-temperature performance |
| LOCTITE SI 5950 | Silicone | FIPG | RTV moisture cure | Paste | — | Industrial flange sealing | Flexible general-purpose RTV gasketing |
| LOCTITE SI 596 | Silicone | FIPG | RTV moisture cure | Paste | High-temperature | Flanges / high-temperature sealing | Good load bearing and temperature resistance |
| LOCTITE SI 5970 | Silicone | FIPG | RTV moisture cure | Black thixotropic paste | — | Stamped sheet-metal covers | Oil-resistant flexible gasketing |
| LOCTITE SI 598 | Silicone | FIPG | RTV moisture cure | Black thixotropic paste | -54 to 260 | Oil pans, transmission pans, covers | Excellent engine-oil resistance |
| LOCTITE SI 5999 | Silicone | FIPG | RTV moisture cure | Grey thixotropic paste | Up to 250 | Automotive powertrain gasketing | Non-corrosive; blow-out resistant |
| PERMABOND LH197 | Anaerobic acrylic | FIPG | Anaerobic cure | 20,500–50,000 cP | -55 to 150 | Soft / dissimilar metal flanges | Flexible and easy to remove |
| PERMABOND MH196 | Anaerobic acrylic | FIPG | Anaerobic cure | 100,000–500,000 cP | -55 to 200 | Metal flange gasketing | Fast cure; high-temperature resistance |
| Permatex Form-A-Gasket No. 1 Sealant | Resin-based | FIPG / gasket dressing | Solvent evaporation | Hard-setting paste | -54 to 204 | Rigid flanges / pre-cut gaskets | Hard-setting; fuel and oil resistant |
| SILASTIC 3-8186 Thixotropic Foam | Silicone foam | CIPG | 2-part, 1:1 / heat cure | Thixotropic foam | — | Electronics / enclosure gasketing | Low-force compression gasket |
| SILASTIC 8257 Silicone Foam | Silicone foam | CIPG | 2-part room-temperature cure | Foam | — | Electronics / enclosure gasketing | Soft silicone foam; room-temperature cure |
Frequently Asked Questions
Frequently Asked Questions about Gasketing Sealants (CIPG & FIPG)
What is the difference between CIPG and FIPG?
Cure-in-place gaskets (CIPG) are applied to a component and cured before the assembly is put together, allowing the part to be disassembled and reassembled later without needing a replacement gasket. Form-in-place gaskets (FIPG) are applied and the assembly is closed while the material is still uncured, so the gasket cures in situ against both mating surfaces, forming a permanent bond as part of the assembly process.
What materials are commonly used for CIPG and FIPG gaskets?
Polyurethane and silicone are the most common chemistries. Two-part polyurethane sealants cure into thick solids or foams with strong elongation and adhesion to metals, plastics, and composites. RTV silicones cure at room temperature, with heat, or under UV light, and offer gap-filling capability along with broad temperature and chemical resistance.
Do gasketing sealants require a primer?
RTV silicone gasketing sealants generally adhere well to a wide range of substrates without requiring a primer. Primer needs vary by specific formulation and substrate, so product-specific data should always be checked, particularly for challenging or low-surface-energy substrates.
What is dual-cure silicone gasketing, and why is it used?
Some cure-in-place silicone gasket sealants use a dual-cure mechanism: a rapid UV cure sets the bead quickly enough for assembly, followed by a secondary moisture cure that continues even in shaded or UV-blocked areas the light couldn't reach. This combination allows the sealant to fully cure to depths of several millimeters without leaving uncured material underneath the visible surface.
What temperature range can gasketing sealants withstand?
RTV silicone gasketing sealants can generally operate across a wide continuous temperature range and tolerate brief exposure to higher peak temperatures, retaining resilience and adhesion even after thermal aging. Exact service and peak temperature ratings vary by specific formulation, so product-specific data should be checked for demanding thermal applications.
Are there limitations to using silicone for gasketing applications?
Yes. RTV silicones generally have poorer resistance to fuel and aromatic solvents compared to other chemistries, and their lower tensile and shear strength can make them less suitable for heavily stressed or high-pressure sealing applications. Polyurethane or another chemistry may be a better fit where fuel exposure or high mechanical load is expected.
Learn More
Cure-in-Place Gaskets (CIPG)
CIPG is a sealing technology that involves applying a liquid gasket material onto a surface, where it cures or solidifies in place before the assembly is closed. This method is commonly used where precise, complex shapes are required for effective sealing, and the liquid gasket material typically consists of a polymer base and curing agents.
Key characteristics of CIPG include its ability to conform to irregular surfaces, creating a customized, seamless seal. This technology is known for its resistance to a wide range of temperatures, chemicals, and environmental conditions. The cured gasket provides reliable, durable sealing, making it well suited to applications in automotive engines, gearboxes, and other critical components.
CIPG Chemistry Comparison
Polyurethane
Two-part sealants that, once mixed and cured, transform into thick solids or foams with excellent elongation and adhesion. They adhere well to metals, plastics, and composites, and resist dilute acids, bases, and light oils. Hardness ratings generally range from 20 (Shore 00) to 60 (Shore A).
Silicone (RTV)
Solvent-free, one- or two-component sealants that cure at room temperature, with heat, or under UV exposure. They offer gap-filling capability up to 6mm and generally adhere without a primer. Effective across a wide continuous temperature range with brief tolerance for higher peaks, RTV silicones resist common oils and coolants and hold up well against weathering, vibration, moisture, and ozone.
Dual-Cure Silicone: Certain cure-in-place silicone gasket sealants use a dual-cure mechanism. A rapid UV cure establishes the bead with enough strength for assembly, followed by a moisture cure that continues even in shaded areas the light can't reach, allowing effective cure to depths up to 6mm.
Limitations of RTV Silicone: RTV silicones have relatively poor resistance to fuel and aromatic solvents, and their lower tensile and shear strength may make them a weaker fit for heavily stressed or high-pressure sealing applications.
Form-in-Place Gaskets (FIPG)
FIPG is valued for its flexibility and adaptability, conforming seamlessly to the unique shapes and contours of mating surfaces. This not only ensures precision during application but also minimizes the risk of misalignment, contributing to a consistently reliable seal.
FIPG offers versatility through a range of material options, allowing customization based on specific application requirements; commonly used materials include silicone, rubber, and other elastomers, each providing distinct properties tailored to different sealing needs. Curing typically takes place in situ as the assembly is completed, and the specific process may involve moisture curing, heat curing, or a combination of both, depending on the formulation.
FIPG is often preferred for its ability to automate the gasket application process, reducing labor costs and ensuring consistent results. Like CIPG, FIPG materials are typically liquid or semi-liquid at the time of application and solidify to form a resilient gasket, offering excellent adhesion to a wide range of surfaces and seeing extensive use across electronics, appliances, and machinery.
FIPG is particularly well suited to intricate assemblies, such as automotive engines, electronic enclosures, and industrial machinery. The choice of FIPG material is determined by factors such as temperature requirements, chemical compatibility, and the specific conditions of the application.
Gasket Sealant Applications
CIPG and FIPG are used across a variety of applications, including automotive and electrical components.
Automotive
CIPG and FIPG are extensively used in the automotive industry for sealing engine components, oil pans, transmission housings, and other critical assemblies. Their ability to withstand temperature variations and resist automotive fluids makes them indispensable in this sector.
Electronics
In electronic manufacturing, CIPG and FIPG are used for sealing and insulating electronic components. These gaskets protect against moisture, dust, and environmental contaminants, supporting the reliability of electronic devices.
Need Help Selecting the Right Gasketing Sealant?
Chemistry selection depends on your assembly method, substrate, chemical exposure, and service temperature. Our technical team provides product selection support, trial quantity sourcing, and application guidance across CIPG and FIPG polyurethane and silicone systems.
CIPG vs FIPG – Quick Reference