UV Adhesives

Ultra Low Viscosity UV Resin: Applications and Challenges

Some bonding jobs need a resin that behaves almost like water: flowing into a 50-micron gap, wicking along a seam by capillary action, and cross-linking in seconds under a lamp. Ultra low viscosity UV resin does exactly that, and its thin body is both its main advantage and its main handling problem. What "Ultra Low Viscosity" Means Viscosity for these resins typically sits below 50 centipoise, close to that of a light oil, and some grades run under 20 cP. That low resistance to flow lets the resin penetrate tight bond lines and porous surfaces without pressure. Cure is by ultraviolet or visible light through a photoinitiator, so the material stays liquid until exposure and then gels within seconds. The Incure Optik UV optical adhesive line includes low-viscosity grades such as 1702 formulated for exactly this behavior, with controlled refractive index for clear assemblies. Where It Is Used Electronics assembly: wicking into fine gaps to encapsulate delicate components, seal connector backshells, and bond sensors where a thicker adhesive would bridge rather than penetrate. Optics and photonics: bonding lenses, prisms, and fiber ferrules where the bond line must be thin, uniform, and free of trapped air, and where refractive-index matching preserves optical performance. Precision instrumentation: fixing small mechanical assemblies, wire terminations, and micro-machined parts that cannot tolerate stress from a high-shrinkage adhesive. Microfluidic and analytical devices: sealing channel lids to substrates in industrial flow cells and lab-on-chip test hardware without blocking the channels. Rapid prototyping and repair: stabilizing thin cross-sections and hairline cracks that a viscous resin cannot enter. For curing these small, precise bonds, a UV LED spot lamp matched to lightguide reach and working distance delivers focused energy exactly where it is needed. Larger batches move to a UV lamp sized for resin curing. The Handling Challenges Contamination sensitivity. A thin resin picks up and carries dust, fibers, and skin oil readily. Any particle in the bond line scatters light in an optical path and creates a stress riser in a structural one. Work clean: filtered dispensing, covered reservoirs, and lint-free wipes. Migration and run-off. Capillary action does not stop at the joint. Resin can wick onto surfaces you did not intend to bond, into threads, or across an optical face. Control dispense volume tightly and use dams or masking where creep matters. Shallow gap-fill only. Low viscosity comes from low filler and low molecular weight, so these resins shrink more and bridge gaps poorly. They are for thin, well-fitted joints, not for filling a 1 mm void. Oxygen inhibition at the surface. The air-exposed skin of any acrylate can stay tacky. An inert blanket, a top coat, or sufficient dose overcomes it. Not sure whether an ultra low viscosity grade suits your gap and geometry? Email Us with your bond-line dimensions and substrate. Process Control Delivered dose governs cure quality. Dose is irradiance multiplied by exposure time, measured in millijoules per square centimeter. Because lamp output falls with hours of use and light guides lose transmission, check irradiance…

Comments Off on Ultra Low Viscosity UV Resin: Applications and Challenges
November 27, 2024
Epoxy / Putty

High-Temperature Epoxy: A Solution for Extreme Environments

Standard epoxy is prized for strength and adhesion, but most grades start to soften somewhere between 60 and 90°C. High-temperature epoxy is engineered to hold its mechanical properties well above that, making it the material of choice where heat would defeat an ordinary bond. What Sets High-Temperature Epoxy Apart The key metric is glass transition temperature (Tg), the point at which the cured polymer shifts from a rigid glass to a soft, rubbery state. Above Tg, shear and tensile strength drop steeply. High-temperature epoxies use aromatic hardeners, specialized curing agents, and often mineral or ceramic fillers to push Tg into the 150 to 250°C range, with some formulations rated for short-term exposure much higher. Alongside raised Tg, these grades typically offer: Retained strength at temperature, not just survival of a heat spike. Low coefficient of thermal expansion, often through ceramic or silica filler, which limits dimensional drift. Oxidative and chemical stability so the polymer does not embrittle during long hot service. Where It Is Used Automotive and motorsport: bonding and sealing near exhaust manifolds, turbochargers, and engine covers where under-hood temperatures routinely exceed 120°C. Aerospace: structural bonding of composite and metal assemblies, plus sealing around bleed-air and engine nacelle components. Electronics: die attach, encapsulation, and coil bonding where resistive heating and power density raise local temperatures. For high-power resistor and heater coatings, ceramic-filled dielectric grades are common. Energy: downhole tools, geothermal equipment, and solar concentrator assemblies exposed to sustained heat. Industrial process equipment: bonding and patching on ovens, dryers, kilns, and steam systems. For external surfaces that must radiate heat or survive flame contact, high-emissive ceramic coatings selected by substrate and service temperature often pair with a high-temperature epoxy bond underneath. Cure and Post-Cure High-temperature epoxies almost always require a heat cure and a post-cure to reach full Tg. A representative schedule ramps to an initial cure temperature, holds, then steps up to the post-cure temperature for one to several hours before a slow cool-down. Curing at room temperature alone can leave the polymer 40 to 60°C short of its rated Tg and dramatically weaker when hot. Control the ramp rate. Fast heating traps reaction exotherm in thick sections, which can char the resin or generate porosity from escaping volatiles. Not sure which grade and cure schedule your assembly needs? Email Us with your continuous and peak temperatures and substrate list. Designing the Joint Heat magnifies the effect of expansion mismatch. When a high-temperature epoxy bonds steel to aluminum, or metal to ceramic, each thermal cycle shears the bond line because the two substrates grow at different rates. A filled, lower-CTE epoxy reduces the internal stress, and joint geometry does the rest. The underlying mechanism is laid out in this explainer on how CTE mismatch causes adhesive bond failure. Practical guidance: Keep bond lines thin and uniform, 0.1 to 0.3 mm, to limit stress and voids. Favor shear-loaded lap joints over peel or cleavage. Radius sharp corners where stress concentrates. Verifying Performance Rate the epoxy on wet Tg, since absorbed…

Comments Off on High-Temperature Epoxy: A Solution for Extreme Environments
November 27, 2024
Putty

Incure Epo-Weld™ Heat-Resistant Epoxy Resin for High-Temperature Metal Repair

Rebuilding a load-bearing section of a pump casing, a turbine housing, or a cast-iron manifold takes more than a surface filler. It needs a two-part, structurally reinforced compound that machines like metal and holds its strength at temperatures that destroy ordinary resins. Where a two-part system earns its place One-part ceramic pastes are convenient for sealing and thin fills, but they build strength slowly and stay comparatively brittle. A two-part, aluminum-and-ceramic reinforced compound cures by a controlled chemical reaction rather than by drying, so it develops higher compressive and shear strength, bonds more aggressively to prepared metal, and can be applied in thicker sections without shrinkage cracking. Incure's Epo-Weld™ heat-resistant repair resin is a two-part paste mixed at a 2:1 ratio. The cured compound tolerates continuous service to roughly 750°C (1,385°F) and short excursions higher. It is aimed at repairs that carry stress: worn bearing seats, eroded impeller vanes, cracked housings, and gouged sealing surfaces on automotive, aerospace, foundry, and power-generation equipment. Getting the mix right Two-part accuracy matters. Measure the resin and hardener by weight or with the supplied volumetric tools, and mix until the color is completely uniform with no streaks. Under-catalyzed material stays soft and never reaches rated temperature resistance; over-catalyzed material exotherms, cures too fast to place, and can crack. Mix only what can be applied within the stated working time, which shortens as batch size and ambient temperature rise. Scrape the mixed compound from the sides and bottom of the container into the batch at least once during mixing. Unmixed resin clinging to the container wall is a frequent source of soft spots in an otherwise sound repair. Surface preparation Machine or grind the damage back to sound metal and give the area a coarse, angular profile by grit blasting or with a carbide burr. Undercut the edges of a cavity slightly so the cured plug is mechanically keyed in place rather than relying on adhesion alone. Degrease with a clean solvent immediately before applying, and do not touch the prepared surface with bare hands. Press the first thin layer of compound hard into the profile to wet it fully, then build up to slightly above the finished contour. For a discussion of why a rebuilt area can still let go at the bond line, see how CTE mismatch causes adhesive bond failure. Cure and post-cure Allow the repair to cure at room temperature until it is hard enough to machine, typically overnight. Then post-cure with a stepped heat ramp: a hold near 100°C, a hold near 200°C, and a final hold near 350°C before the part sees full operating temperature. The stepped ramp completes the crosslink reaction and drives off volatiles gradually. A repair taken straight to service temperature without post-cure can blister or lose a significant fraction of its strength. Once post-cured, the compound can be turned, milled, drilled, and tapped with standard tooling, which is what makes it suitable for restoring dimensional features like bores and faces. Applications Rebuilding worn shaft seats,…

Comments Off on Incure Epo-Weld™ Heat-Resistant Epoxy Resin for High-Temperature Metal Repair
August 10, 2024
Putty

Incure Epo-Weld™ High-Temperature Epoxy for Metal Joint and Defect Repair

A cracked exhaust manifold, a porous casting, or a leaking furnace duct cannot be repaired with a hardware-store epoxy. Conventional organic resins soften and char well before 250°C, so high-temperature metal repair needs a ceramic-based chemistry built for the heat. Why conventional epoxies fail under heat Standard bisphenol-A epoxies are held together by an organic polymer network with a glass transition temperature (Tg) that rarely exceeds 120°C without specialized hardeners. As service temperature approaches Tg, the cured resin loses stiffness, creeps under load, and begins to oxidize. Above roughly 300°C the polymer backbone breaks down entirely, leaving a friable char with almost no cohesive strength. A repair that looks sound at room temperature can fail within hours once the part returns to service. High-temperature ceramic repair compounds solve this by replacing most of the organic content with inorganic fillers and silicate binders. Incure's Epo-Weld™ high-temperature repair paste is a one-part, water-based system loaded with ceramic and stainless steel particles. The binder cures to a rigid, mineral matrix that carries load by particle-to-particle contact rather than by a temperature-sensitive polymer, which is why it holds up in continuous service to about 1,100°C (2,000°F). What the Epo-Weld™ high-temperature repair paste is The material is supplied ready to use as a trowelable paste. Because it is water-based and single-component, there is no mixing ratio to get wrong and no pot-life clock once the container is opened. It bonds to stainless steel, carbon steel, cast iron, and cast aluminum, and it can be feathered to a thin edge or built up in successive layers to rebuild missing metal. Typical uses include: Sealing cracks and pinholes in exhaust stacks, manifolds, and headers Rebuilding eroded or pitted areas on pump housings and valve bodies Patching furnace shells, incinerator liners, and ductwork Filling casting defects such as blowholes and cold shuts before machining Repairing warped or gapped flange faces on high-temperature equipment Surface preparation and application Adhesion to metal depends almost entirely on surface preparation. Grind or grit-blast the repair area to bright, angular metal, then remove all oil and dust with a fast-evaporating solvent. Any oxide scale, paint, or grease left in place becomes the weak layer where the repair eventually lets go. Work the paste firmly into the prepared surface with a stiff spatula so it wets the profile, then build to the final contour. For deep fills, apply in lifts of 6 mm or less and allow each lift to skin over before adding the next, which keeps trapped moisture from blistering the repair during cure. Overfill slightly; the material can be sanded or machined once fully hardened. For guidance on matching a coating or filler to the base metal, see how CTE mismatch causes adhesive bond failure and Incure's overview of high-emissive ceramic coatings by substrate and service temperature. Cure schedule and why the ramp matters Air-dry the repair at room temperature for 24 hours so the bulk of the water leaves the matrix. The final ceramic strength develops only after a controlled…

Comments Off on Incure Epo-Weld™ High-Temperature Epoxy for Metal Joint and Defect Repair
August 10, 2024