The most common metal putty failure is not the wrong product. It is a repair that was shaped after the putty had already begun to set, machined before it had finished curing, or returned to service while it was still gaining strength. Each of those is a clock error, and a metal putty has three clocks. Q: How long does metal putty take to cure? A: It depends which "cure" you mean. Pot life (or working time) is how long after mixing the putty stays shapeable — often 5–20 minutes for fast two-part epoxies, longer for single-component ceramic compounds. Handling or machining time is when the repair is hard enough to drill, tap, or file — Incure's Epo-Weld™ HSS-601 reaches it in 2–4 hours at room temperature. Full cure is when the repair reaches its rated strength and chemical resistance — 24–48 hours at room temperature for HSS-604 and HSS-610, or 2 hours with a 200°F post-cure. Loading the repair before full cure is the failure that looks like a bad product. Clock 1: Pot Life Starts at Mixing, Not at Application For a two-part metal putty, the reaction begins the moment resin and hardener meet. Kneading generates heat, and heat shortens pot life — a large mass mixed in one lump can begin to stiffen before it reaches the part. Mix only what one application consumes, work at the cooler end of the product's recommended temperature range if the shop is hot, and apply immediately. A putty that has started to crumble or roll rather than smear has passed its pot life; it will stick to itself but not to the metal. Single-component ceramic compounds such as Incure's Epo-Weld™ HTCP-550 and HTCP-950 are water-based and air-curing, so their working time is governed by evaporation rather than a chemical clock — longer and more forgiving, but they still skin over, and a skinned surface will not bond a second layer. Clock 2: Machining Time Depends on Filler and Temperature Metal putties are filled epoxies, and the filler decides what the cured repair can do. Incure's HSS-604 is aluminum- and ceramic-filled specifically so the cured repair machines, drills, and taps like metal — at Shore D84–D94 and 14,500 PSI flexural strength — while the glass-fiber- and kevlar-reinforced HSS-601 (13,500 PSI flexural) is built to resist crack propagation and abrasion on chutes, hoppers, and pump casings rather than to be machined to a dimension. Machining before the putty reaches handling strength tears filler out of the matrix and leaves a porous surface; machining a fully cured HSS-604 produces a metal-like finish. The grade-by-grade breakdown is in Incure's High Strength Structural Epoxy guide. Temperature moves this clock more than any other variable. Epoxy cure rate roughly doubles for every 10°C rise, so a repair that machines in 4 hours at 25°C may need 8 at 15°C. A post-cure at the product's rated temperature — 175°F for HSS-601, 200°F for HSS-604/610 — collapses a two-day room-temperature schedule into hours. Email Us with the component,…

A "heat resistant glue for plastic" rated to 150°C can still fail at 110°C — because the plastic softened first, because the rating was a peak rather than a continuous figure, or because the adhesive passed its glass transition and stopped carrying load long before it decomposed. Three numbers on two data sheets decide whether a hot plastic joint holds, and most specifications read only one. Q: What is heat resistant glue for plastic, and how hot can it go? A: It is an adhesive whose cured bond keeps useful strength at elevated temperature on plastic substrates: typically a high-temperature cyanoacrylate (Incure's Heat-Resist™ grades are rated to 135–145°C), a UV-curable acrylate with an extended rating (Incure's highest-viscosity Uni-Weld™ plastic-bonder grade is rated −55°C to 150°C, against 80°C for most of the line), or a heat- or room-temperature-cure epoxy for higher ceilings. "How hot" has three answers: the adhesive's continuous service rating, its glass transition temperature, and the heat deflection temperature of the plastic itself — and the joint is limited by the lowest of the three. Number 1: Continuous vs. Peak Service Temperature Adhesive data sheets quote a temperature ceiling, and it matters whether that figure is continuous or intermittent. A continuous rating means the bond holds its specified strength indefinitely at that temperature; a peak or short-term rating means it survives brief excursions. A 145°C ceiling on a cyanoacrylate such as Heat-Resist™ 311 or 340 — the highest in that line — is a different design margin from a 145°C peak figure on a general-purpose grade. If the sheet does not say which, assume peak and ask. Grade-level detail across the line is in Incure's Heat-Resist™ high-temperature cyanoacrylate guide. Number 2: Glass Transition Temperature (Tg) Every cured polymer adhesive has a Tg — the temperature at which it changes from a rigid, glassy solid to a soft, rubbery one. Above Tg the adhesive has not failed, but its modulus can drop by an order of magnitude and its creep resistance largely disappears. A structural joint that must hold load and dimension should run below the adhesive's Tg; a flexible joint whose job is sealing or vibration damping can run above it. Many high-temperature cyanoacrylates and acrylates are rated to a ceiling above their Tg, which is fine for a sealed or lightly loaded bond and wrong for a load-bearing one. Ask for the Tg, not just the ceiling. Email Us with the plastic, the continuous and peak temperatures, and whether the joint carries load, and Incure's engineers can identify which adhesive rating actually governs your assembly. Number 3: The Plastic's Heat Deflection Temperature The adhesive is often not the weakest link. Common engineering plastics soften well below the ceiling of a heat-resistant adhesive: ABS deflects under load around 90–100°C, polycarbonate around 130–140°C, PMMA around 90–100°C, nylon 6 (dry) around 70–80°C at high stress, and only materials such as PEEK, PPS, or PEI reach 150°C and above. An adhesive rated to 145°C bonding ABS at 120°C is bonding a substrate…

Carbon fiber itself is stable past 2,000°C in an inert atmosphere, yet a carbon fiber part routinely fails at 150°C. The fiber isn't the problem. The resin holding it together — and any adhesive joining it to something else — decides how heat resistant a carbon fiber component actually is. Q: Is carbon fiber heat resistant? A: The fiber is; the composite usually isn't. Bare carbon fiber tolerates extreme temperature and does not melt, but in air it begins to oxidize at roughly 400°C and above. In practice the fiber is always embedded in a polymer matrix, and that matrix governs the part: standard epoxy laminates are limited to about 120–180°C by their glass transition temperature, high-temperature epoxies and cyanate esters reach 200–250°C, and only bismaleimide or polyimide matrices approach 300°C. Any adhesive used to bond or repair the part must be rated at least as high as the matrix and, ideally, higher. Why Tg Governs a Composite A laminate's stiffness comes from load transfer between fibers through the resin. Below the resin's glass transition temperature (Tg), that transfer is efficient and the part behaves as designed. Above Tg the resin softens, interlaminar shear strength drops sharply, and the laminate loses stiffness even though the fibers are untouched. A composite is therefore rated not by what the fiber can survive but by the temperature at which the matrix stops doing its job — typically 20–30°C below the measured Tg to preserve margin. "Heat resistant carbon fiber" in a product specification almost always means "carbon fiber in a high-Tg matrix." Bonding Carbon Fiber for Elevated Service Bonded joints on carbon fiber parts fail at temperature for the same reason the laminate does: the adhesive passes its own Tg. Two selection rules follow. First, the adhesive's continuous service rating and Tg must exceed the part's operating temperature, not just its matrix's rating. Second, the adhesive's thermal expansion should be as close as possible to the laminate's — carbon fiber composites expand very little (near zero to a few ppm/°C along the fiber direction), so a high-expansion adhesive between a carbon fiber part and an aluminum fitting (23 ppm/°C) takes up a large mismatch on every cycle. The stress mechanism is set out in Incure's guide to CTE mismatch in bonded joints. Incure's Epo-Weld™ high-temperature epoxy line includes grades built for exactly this combination. HTE-5374 pairs a high glass transition temperature with low thermal expansion for bonds that must hold dimension as they heat; HTE-5361 is formulated for low-outgassing precision alignment where the composite part is an optical or instrument structure. The grade-by-grade profile — hardness from Shore D60 to D95, cure paths from room temperature to accelerated oven schedules — is in Incure's Epo-Weld™ high-temperature epoxy guide. Email Us with the laminate's matrix system, the mating material, and the continuous and peak service temperatures, and Incure's engineers can identify an adhesive whose Tg and expansion fit the joint. When the Service Temperature Exceeds a Standard Epoxy For carbon fiber structures in exhaust-adjacent,…

"Flange sealant" covers two very different ways of replacing a cut gasket, and picking the wrong one is why some flanges weep at the first thermal cycle while others seal for a decade. One cures in the dark between tightly mated metal faces; the other cures in seconds under UV light as a shaped, compressible bead. Here is how to tell which your flange needs. Q: What is a flange sealant, and how does it differ from a form-in-place gasket? A: A flange sealant is usually an anaerobic liquid: it stays fluid in air and cures only when confined between close-fitting metal surfaces, filling microscopic voids so the two faces seal metal-to-metal under clamp load. A form-in-place (FIP) or cure-in-place (CIP) gasket is a dispensed bead cured on the part — under UV light in Incure's Uni-Seal™ line — into a compressible elastomer that seals by being squeezed between the faces like a rubber gasket. Anaerobics suit rigid, precisely machined metal flanges with near-zero gap; FIP/CIP gaskets suit larger gaps, non-metal or dissimilar flanges, and joints that will be opened for service. How Anaerobic Flange Sealants Seal Anaerobic chemistry needs two things: exclusion of oxygen and contact with metal ions, which catalyze the cure. That is why it works between two steel or aluminum faces bolted together and stays liquid on a plastic flange or in an open gap. The cured film is thin and rigid, holds clamp load without creep, and resists most fluids. Its limits follow from its chemistry: gaps beyond roughly 0.25–0.5 mm cure slowly or not at all in the center, inactive surfaces (stainless, plated, anodized, plastic) need a primer or cure very slowly, and disassembly means scraping the cured film off both faces. Application practice for this class — surface prep, bead placement, bolt-up timing — is covered in Incure's flange sealant application guide. How a UV-Cured Form-in-Place Gasket Seals A CIP gasket bead is dispensed onto one flange face and cured under UV light before the joint is assembled — Incure's Uni-Seal™ grades cure in seconds at 365–405 nm. The result is a permanent, compressible elastomer bonded to one face and simply compressed by the other, which changes what the joint can tolerate. The Uni-Seal™ UV gasket line spans Shore A5 elastomers to Shore D85 rigid sealants: the soft Shore A grades — 1366, 3301, 3339, and the 3368 family — compress under clamp load like a rubber O-ring and deliver IP68-rated sealing, with 3339 at A5–A15 built specifically as a form-in-place gasket replacement. Because the bead is cured before assembly, the mating face can be plastic, painted, anodized, or stainless without affecting cure, the gap can be whatever the bead height bridges, and the joint opens and re-closes on the same gasket. Email Us with the flange materials, the gap or flatness tolerance, the fluid, and whether the joint will be serviced, and Incure's engineers can confirm which sealing approach — and which grade — fits. Choosing Between Them: Five Questions What are…

Ask whether super glue works on metal and the honest answer is "yes, on the day you apply it." Whether it still works after a year of vibration, humidity, and thermal cycling is decided by the twenty minutes of preparation before the bead goes down. This is the protocol that separates the two outcomes. Q: Does super glue work on metal? A: Yes. Cyanoacrylate (super glue) bonds steel, aluminum, copper, brass, and stainless steel, reaching up to 5,200 PSI on steel and 3,200 PSI on aluminum with an industrial grade such as Incure's Heat-Resist™ line. It works because cyanoacrylate cures by reacting with trace surface moisture, which every metal carries. It fails when the surface is oily, oxidized, or too smooth, when the joint is loaded in peel rather than shear, or when service temperature exceeds the grade's ceiling — 135–145°C for Heat-Resist™ grades, lower for general-purpose formulations. Step 1: Remove What the Glue Can't Bond Through Cyanoacrylate bonds to the outermost molecular layer of whatever it touches. On an as-received metal part that layer is machining oil, fingerprint residue, or an oxide film — not metal. Wipe with a lint-free cloth and a solvent that leaves no residue (isopropyl alcohol or acetone; never a lubricating "contact cleaner"), then do not touch the bond area again. Aluminum deserves extra attention: its oxide reforms within minutes of abrasion, so abrade and bond in the same session. Copper and brass tarnish similarly; a fresh abrasive pass immediately before bonding is the difference between bonding to metal and bonding to tarnish. Step 2: Give the Adhesive Something to Grip A mirror-polished surface offers cyanoacrylate very little mechanical keying. Light abrasion with 180–320 grit paper or a fine abrasive pad raises surface area and gives the cured adhesive microscopic anchors. Abrade in one direction, solvent-wipe again to remove the abrasive dust, and confirm the surface is water-break-free: a drop of clean water should sheet out rather than bead. Beading means residual contamination and predicts a weak bond. Step 3: Match Viscosity to the Gap Cyanoacrylate is strongest as a thin film — typically a few thousandths of an inch. Two flat, well-mated metal faces call for a low-viscosity grade that flows into full contact: Incure's Heat-Resist™ 320, at 260–370 cP, is thin enough to wick into an already-assembled joint by capillary action. Where the mating faces are slightly out of flat, a medium grade such as Heat-Resist™ 319 or 328 (400–600 cP) fills without running. For rough castings or a joint that also includes rubber, ceramic, or fiberglass, the high-viscosity Heat-Resist™ 311 and 340 (2,000–3,000 cP) bridge irregularities and carry the widest substrate range in the line. Grade selection across the full line is laid out in Incure's Heat-Resist™ high-temperature cyanoacrylate guide. Email Us with the two metals, the joint geometry, and the service temperature, and Incure's engineers can confirm which cyanoacrylate grade fits — or whether the joint actually needs a different chemistry. Step 4: Design the Joint for Shear, Not Peel Cyanoacrylate…

A cyanoacrylate bond on glass looks perfect at the bench, and that is precisely the problem: the failures show up weeks later, after humidity, a dishwasher cycle, or a cold night has done what a pull test at minute ten never could. Before committing super glue to a glass assembly, run these six tests. Q: Does super glue work on glass? A: It bonds — cyanoacrylate cures on glass within seconds and reaches useful strength on a clean, dry surface. But three properties of glass work against it in service: the alkaline surface and adsorbed moisture on glass slowly attack the cyanoacrylate interface, humidity degrades the bond over months, and glass's low thermal expansion against a rigid adhesive and a metal or plastic partner builds stress on every temperature cycle. For a one-time repair, super glue is usually fine. For a product, qualify it with the tests below or specify a glass-formulated UV-curable adhesive instead. Incure's overview, Does Super Glue Work on Glass, and Should You Use It?, explains the chemistry; this post is the test plan. Test 1: Water-Break and Initial Adhesion Clean the glass with isopropyl alcohol, then check that a drop of water sheets across the surface rather than beading — a beading surface still carries a film the adhesive will bond to instead of the glass. Bond five coupons, cure 24 hours, and pull to failure. Record the failure mode, not just the load: adhesive failure (clean glass) indicates a surface or chemistry problem; cohesive failure (adhesive on both faces) or substrate failure means the interface held. Test 2: 85°C / 85% RH Humidity Aging Cyanoacrylate's weakness on glass is moisture at the interface. Place bonded coupons in 85°C and 85% relative humidity for 168 hours (or a humidity chamber at whatever your product's environment demands), then pull. A bond that loses more than roughly 30% of its initial strength, or shifts from cohesive to adhesive failure, will not survive a humid service life. Industrial grades such as Incure's Heat-Resist™ line resist alcohol, petrol, and diluted aqueous acids and bases, but no cyanoacrylate is immune to long-term water at a glass interface — this test tells you how long yours lasts. Test 3: Thermal Cycling Cycle bonded coupons between the product's real extremes — −40°C to 85°C is a common electronics profile — for at least 100 cycles, then inspect under magnification for interface cracks before pulling. Glass expands at roughly 8–9 ppm/°C; aluminum at 23 ppm/°C; most plastics at 50–100 ppm/°C. A rigid cyanoacrylate between glass and any of these takes the difference as shear stress on every cycle. Small bond areas tolerate it; a bond line more than a couple of centimeters long typically does not. Email Us with the glass type, the mating substrate, and the environmental profile, and Incure's engineers can advise whether cyanoacrylate can pass these tests for your assembly or whether a UV-curable glass bonder is the right starting point. Test 4: Blooming and Optical Check Cyanoacrylate vapor condenses as…

Every conformal coating chemistry protects a circuit board from moisture, and every one of them has a board it should never be used on. The selection question is rarely "which coats best" — it is which chemistry survives your thermal range, your rework plan, and your production rate. These are the questions that decide it. Q: What is a conformal coating? A: A conformal coating is a thin polymer film — typically 25–250 µm — applied over an assembled PCB to protect it from moisture, dust, chemicals, and temperature extremes while conforming to component contours. It prevents corrosion, leakage current, and dendrite growth between closely spaced conductors. The main chemistries are acrylic, silicone, urethane, epoxy, parylene, and UV-curable formulations, applied by brush, spray, dip, or selective dispensing. Q: How thick should it be? A: Thickness is set by chemistry and inspected against IPC-A-610's published ranges: roughly 30–130 µm for acrylic, urethane, and epoxy; 50–210 µm for silicone; 10–50 µm for parylene. Too thin leaves pinholes and uncovered edges; too thick traps stress, cracks at component leads under thermal cycling, and bridges connector contacts. Measure wet film during application and dry film after cure — the two are not the same number. Q: When is acrylic the right choice? A: When rework matters and the environment is moderate. Acrylics dry by solvent evaporation, apply easily, and dissolve in common solvents, so a coated board can be reworked with minimal effort. Their limits are chemical resistance and continuous service temperature, which are lower than silicone or urethane. Q: When is silicone the right choice? A: When the board sees wide thermal swings or continuous high temperature. Silicone stays flexible from far below freezing to well above 150°C, absorbs the expansion mismatch between components and laminate, and damps vibration. Its trade-offs are lower abrasion and solvent resistance and a soft surface that picks up contamination. Incure's Pyra-Sil™ silicone conformal coatings cover this class across a range of viscosities and cure paths. Q: When is urethane the right choice? A: When chemical and abrasion resistance dominate — fuel vapor, hydraulic fluid, solvents, or a handling environment that would scuff a softer film. Urethanes are tough and hard; that same hardness makes them stressful on leaded components under thermal cycling and difficult to rework. Email Us with the board's thermal range, the fluids it meets, the rework plan, and the production volume, and Incure's engineers can identify which chemistry — and which grade — fits before a sample is coated. Q: When is UV-cure the right choice? A: When throughput is the constraint. Solvent-based coatings need minutes to hours to dry; a UV-curable coating cures in seconds under 365–405 nm light, with no solvent emissions and no drying oven. Incure's Ultra-Illumina™ line illustrates the range within one chemistry: 3511 at 100–200 cP flows into fine gaps for uniform, low-profile general coverage; 3552 at 300–600 cP is an aromatic urethane-acrylate with roughly 45% elongation built to absorb thermal-expansion mismatch around power components and BGA corners; 5454F…

A replaced smartphone screen that lifts at one corner after a month didn't fail because the adhesive was weak — it failed because nobody specified what "strong enough" meant. Industry standards exist for exactly that question, and reading them changes which adhesive you choose. Q: What adhesive do industry standards point to for smartphone screen replacement? A: No single standard names an adhesive. Instead, standards define the tests a bonded display must pass — ingress protection (IEC 60529, the "IP68" rating), environmental stress (IEC 60068-2 humidity, thermal cycling, and shock methods), mechanical drop (MIL-STD-810 transit-drop procedures are widely borrowed), and adhesion strength (ASTM D1002 lap shear, ASTM D903 peel). The adhesive that passes those tests on your frame and glass is the "correct" one. In practice that means a flexible, optically clear, controlled-viscosity UV-curable or pressure-sensitive system — never a rigid cyanoacrylate, which clouds displays, stresses glass, and offers no rework. What the Standards Actually Test Ingress protection. IEC 60529 defines the IP code; IP68 means dust-tight and rated for continuous immersion under conditions the manufacturer specifies. A perimeter seal that bonds the display module to the frame is the water barrier, so the adhesive is being tested as a gasket as much as a bond. Environmental durability. IEC 60068-2 methods cover damp heat (typically 85°C/85% RH), thermal cycling (−40°C to 85°C is common for consumer devices), and vibration. A screen adhesive must hold through hundreds of cycles between materials with very different expansion rates — glass at roughly 8–9 ppm/°C, aluminum frames at 23 ppm/°C, polycarbonate at 65–70 ppm/°C. Drop and impact. Repeated 1–1.5 m drops onto a hard surface, on each face and edge, are the standard benchmark. The adhesive must absorb shock rather than transmit it into the glass edge. Adhesion strength. ASTM D1002 lap-shear and ASTM D903 peel tests characterize the bond itself. For a screen, peel resistance matters more than raw shear, because lifting starts at an edge. Why the Test Profile Points to a Flexible Adhesive Every one of those tests punishes rigidity. Incure's Uni-Weld™ plastic bonder guide illustrates the range available in a single UV-curable line: Uni-Weld™ 1072 cures to 13% elongation at Shore D76–D86 — rigid, appropriate for a precision optical mount, wrong for a perimeter seal — while Uni-Weld™ 1483 reaches roughly 3,800% elongation at Shore D50–D60, formulated to absorb vibration and thermal expansion. Grades such as 1417 (346% elongation) and 1444 (355%) sit between, carrying structural load while still damping movement. A screen-to-frame bond lives in that middle-to-high elongation band. Viscosity decides the process. A perimeter bead on a frame ledge needs a grade that holds a fine, consistent line without wicking under the display — the mid-range 1,900–11,400 cP grades. A glass-to-glass or cover-glass lamination is a different job entirely: the requirement is optical clarity and low shrinkage, covered by Incure's Optik™ UV optical adhesive guide. Email Us with the frame material, glass type, and the IP or drop rating the device must meet, and Incure's engineers can identify…

Two clear casting resins can sit side by side on a bench, cure under the same UV lamp, and behave in opposite ways: one hardens the instant the light is on and stays tacky on top no matter how long the exposure runs, while the other looks under-cured when the lamp switches off and is rock-hard an hour later. Neither lamp nor resin is defective — they are two different photochemistries, and the lamp decision has to start with which one is in the pot. Q: What UV curing lamp cures resin, and at what wavelength, distance, and time? A: Light-curable resins respond in the 365–405 nm UVA-to-visible band; 395–405 nm penetrates deeper for thick sections, while cationic epoxies often prefer shorter, broad-spectrum UV. Consumer lamps are rated in electrical watts, which says nothing about light reaching the part — industrial sources are specified in irradiance (mW/cm²) at a stated working distance, typically 1–3 inches for flood lamps. Cure time is whatever exposure delivers the resin's required dose (irradiance × seconds): seconds to a few minutes for free-radical grades, plus a dark-cure period for cationic grades. The chemistry decides the rest. Two Cure Mechanisms, Two Sets of Lamp Requirements Light-curable resins fall into two families. Free-radical systems — the acrylate and urethane-acrylate resins that make up most "UV/visible light curing" grades — polymerize only while photons are arriving; switch off the lamp and the reaction stops within a fraction of a second. Cationic systems — epoxy-based resins cured by a ring-opening mechanism — are started by light but keep polymerizing in the dark for minutes to hours after exposure. Everything that matters about lamp selection for resin follows from that one difference: how much intensity is needed, whether the surface will cure, how deep a section can be, how much heat the cure generates, and when a part can be judged "done." Incure's Cast-Max™ line contains both families, which makes it a useful reference. Grades 1045, 1049, 2013, 2033, 2613, and 2664 are free-radical UV/visible-light-curing resins; grades 2063, 6755, 7653, 7673, and 7693 are cationic epoxies described in the catalog as deep-curing and low-exotherm. The grade-by-grade breakdown is in Incure's Cast-Max™ dome coating and casting guide; this post is about what each family asks of the lamp. Free-Radical Resins: Intensity, Coverage, and the Oxygen Problem Because a free-radical resin cures only under illumination, the lamp has to deliver the full required dose to every point of the casting in one continuous exposure. Three consequences follow. First, irradiance at the surface sets depth of cure. Photons are absorbed as they travel down through the resin, so the bottom of a 10 mm section sees a small fraction of what the top sees. Higher surface irradiance pushes usable light deeper, and longer wavelengths — the 405 nm end of the UV/visible range these grades respond to — are absorbed less strongly near the surface and penetrate further than 365 nm. For deep castings in a free-radical grade, an LED source at 395…

Most UV curing LED specifications start with wavelength and intensity and only later ask how the light will physically reach the adhesive — and that ordering is backwards. A 7,500 mW/cm² spot lamp cannot cure a 12-inch gasket bead in one shot, and a 12-inch flood lamp cannot avoid irradiating the UV-sensitive sensor sitting 3 mm from a hairline bond. Form factor is the first decision, because it determines which intensity figures are even relevant. Q: What is a UV curing LED, and how does it differ from a mercury lamp? A: A UV curing LED is a solid-state source emitting a narrow band — 365, 385, 395, or 405 nm — that triggers photoinitiators in adhesives, coatings, and resins. Against mercury-arc lamps it offers instant on/off, no warm-up, no mercury, far lower infrared heat on the part, and 15,000–20,000-hour rated life. Its limits: no UVB/UVC output (some cationic and surface-cure chemistries still favor arc lamps), and line-of-sight delivery, so shadowed 3D geometry needs the right head shape — which is the subject of this guide. Why Geometry Comes Before Wavelength Every UV curing LED system in Incure's line is available at 365, 385, 395, or 405 nm and factory-configured to a single wavelength, so the wavelength decision is the same across form factors — it follows the adhesive's photoinitiator absorption peak, and it is settled before the order is placed. What differs between form factors is the shape of the cure zone, the working distance the intensity was measured at, how the intensity falls off away from that distance, and whether the head can be enclosed, moved, or fixed. Those four properties decide whether a bond line gets the dose it needs, and no wavelength choice compensates for a mismatch in any of them. The practical method is to draw the bond line first: its length, its width, how far the lamp face or lightguide tip can physically get from it inside the fixture, and what sits next to it that must not be exposed. That sketch points to a form factor before any spec sheet is opened. Spot: Millimeter-Scale Bond Points, Steep Distance Falloff A spot system delivers light through a lightguide to a small circular zone — on Incure's L9000™ spot lamp, a 3 mm to 12 mm spot across a 9–30 mm focal range. Its defining property is intensity that is very high at the focal point and falls off steeply beyond it: 7,500 mW/cm² at 9 mm, 5,000 mW/cm² at 10 mm, 1,200 mW/cm² at 20 mm, and 223 mW/cm² at 30 mm at 365 nm. That falloff is the reason a spot system fits fiber-ferrule bonding, lens tacking, wire-tack points, and individual SMD or connector bonds — the cure zone is tiny, the fixture can hold the guide at a fixed few millimeters, and the surrounding assembly stays dark. It is the wrong choice whenever the fixture cannot guarantee working distance to within a millimeter or two, or the bond is longer than the…