A poured-in-place gasket only works if it seals on the first try and stays sealed through vibration, temperature swings, and chemical exposure. Cut gaskets shift, compress unevenly, and leave gaps at corners. Incure Uni-Seal 3393 is a light-curable form-in-place and cure-in-place gasket material built to seal complex geometries in electronics and automotive assemblies.
Form-in-Place and Cure-in-Place Basics
A form-in-place gasket (FIPG) is dispensed as a bead directly onto one mating surface, then cured before assembly so it behaves like a precision-molded seal. A cure-in-place gasket (CIPG) follows the same idea but is compressed between surfaces during cure. Both approaches eliminate gasket inventory, adapt instantly to design changes, and follow irregular flange paths that a die-cut part cannot.
Why Uni-Seal 3393
Uni-Seal 3393 cures under UV, visible, or LED light and is engineered around the needs of sensitive electronics:
- Acid-free chemistry that will not corrode copper, solder, or fine-pitch leads
- Low viscosity for precise dispensing and penetration into narrow channels
- Tack-free cure leaving a clean, handleable surface with no residue transfer
- Air-tight sealing against moisture, dust, and pressure differentials
- Ease-of-peel rework, so a module can be opened for repair and resealed
- Moisture, temperature, and chemical resistance for under-hood and outdoor service
- Dual use as a temporary mask during downstream conformal coating
Designing a Reliable Poured Gasket
Bead geometry drives the seal. Specify a groove or a defined land width so the dispensed bead has a consistent cross-section and a target compression, generally 20 to 40 percent, when the housing closes. Too little compression leaks; too much extrudes material and can bottom out the joint.
Dispense control is the other half. A positive-displacement dispense head holds bead volume constant as the material warms or the reservoir empties, and programmed paths keep the bead centered on the flange around tight corners. After dispensing, the assembly passes under a lamp sized to the part so the entire bead reaches full cure.
Because a cured gasket and a metal or plastic housing expand at different rates, a seal that is fine at room temperature can open up in the cold or over-compress when hot. Considering how thermal expansion mismatch stresses a bonded or sealed joint guides the choice between a firmer or a more compliant gasket. Matching the material to a suitable UV LED flood lamp or an inline conveyor system keeps cure time in step with line speed.
For help fitting Uni-Seal 3393 to a flange design and dispense process, Email Us with your housing drawings.
Poured Gaskets Versus the Alternatives
Die-cut elastomer gaskets carry a hidden cost: tooling for each new shape, inventory for each part number, scrap from the cut, and assembly labor to place them without pinching or misaligning. They also seal poorly at tight radii and sharp corners, exactly where enclosures tend to leak. A poured gasket forms to the flange path automatically and needs no part-specific tooling.
Room-temperature-vulcanizing (RTV) silicone beads solve the fit problem but cure slowly from the surface inward, so a thick bead can stay soft underneath for hours and the assembly cannot be closed or moved until it sets. A light-curable material such as Uni-Seal 3393 cures on demand in seconds when the bead passes a lamp, which is what makes it viable on a moving line.
Rework and Field Service
Sealed electronics still need to be opened for repair or upgrade. An ease-of-peel gasket lets a technician separate the housing halves, clean the flange, dispense a fresh bead, and reseal, restoring the original protection without machining or solvent soaking. Designing the flange with a defined groove makes that rework repeatable, since the replacement bead has the same cross-section and compression target as the original.
Typical Applications
Poured gaskets seal control-unit housings and sensor enclosures on printed circuit assemblies, connector and module interfaces in automotive electronics, lighting and power-supply enclosures, and equipment housings across industrial machinery. In each case the value is the same: a continuous, custom-fit seal formed in one automated step, with the option to reopen and reseal for service.
Frequently Asked Questions
Q: How much should a poured gasket be compressed?
A: A target of roughly 20 to 40 percent compression of the cured bead height gives a reliable seal without extruding material or bottoming out the joint. The exact figure depends on bead geometry and housing stiffness.
Q: Can a form-in-place gasket be reopened for service?
A: Yes. An ease-of-peel grade lets a technician separate the housing, clean the flange, dispense a fresh bead, and reseal, restoring the original protection level without special tooling.
Work With Incure
Incure formulates acid-free, light-curable FIPG and CIPG materials and supports customers with dispense-path and cure-process development. Contact Our Team to discuss your sealing requirements and request a sample.
Visit www.incurelab.com for more information.