Activators are the support act for cyanoacrylate. A short burst of accelerator triggers curing almost instantly, so a joint does not have to be held for a minute and the glue has no time to creep where it should not. The category covers pump sprays for covering a longer joint and liquid versions applied with a brush or a micro brush. They also solve the slow cases — CA setting lazily in a dry heated room, or a thick bead of gel that the air simply cannot reach.
Cyanoacrylate cures by reacting with airborne moisture. In a thick layer the air never reaches the middle, and setting drags out over long minutes. An accelerator supplies the chemical trigger so the reaction happens at once. From the bench that means two things: the joint holds immediately, and the glue has no time to wick along the surface or run into detail.
Apply glue to one part, bring the parts together, and only then touch the accelerator to the outside of the joint. The reverse order — accelerator first, glue after — is quicker but leaves a weaker, more brittle bond, because the glue never gets to wet both faces.
A spray is fast and suits a long seam or an awkward spot. The drawback is overspray, which can reach the detail nearby. A liquid carried on a brush is dosed exactly and is the better choice on small resin parts and on brass held in tweezers.
An accelerated joint is harder and less forgiving than one left to cure on its own, so on a stressed joint use a smaller dose — or reach for epoxy. Overspray can also fog clear styrene, so keep canopies and glazing out of the cloud.
The textbook case is a brass part or a length of wire that has to sit at an angle in free air. Without an accelerator you hold it in tweezers for a minute and every tremor shifts it. With one, the joint is fixed the instant the part is where you want it. The same applies to a thicker bead of gel, which air barely penetrates, and to work in a dry heated room where CA sets uncomfortably slowly.
When a joint needs patience and room to be aligned instead, leave the accelerator in the drawer and pick a grade from adhesives by viscosity.
