How To Store Super Glue So It Doesn't Dry Out

Super glue is cyanoacrylate, and it cures by reacting with water, including the water vapor in ordinary room air. It is not a solvent-based glue that dries by evaporating. This is why a half-used bottle fails long before an unopened one: every use lets a little moist air in.

A common complaint is that super glue bottles are not filled completely. But actually, the headspace above the glue is deliberate. It does two jobs:

1. It lets allows you to squeeze the bottle. A squeeze applicator needs a pocket of compressible air to work. Take that air away and the bottle turns stiff and unresponsive, so it becomes much harder to get a single drop out instead of a sudden blob.
2. It separates outside air from the glue. The air sealed inside the bottle is dry air. That column of dry air sits between the glue surface and the outside world, so when you uncap the bottle, humid room air meets the top of the headspace instead of the glue itself. The gap acts as a buffer.

What this means in practice:

• Don't top off a bottle or decant super glue into a fuller container.
• Don't try to squeeze the air out before capping. You'd be removing the buffer.

1. The cooler the better. Heat accelerates the reaction that thickens glue in the bottle. A cool, stable indoor spot beats a garage or shed, where the temperature and humidity swing.
2. Keep the cap sealed as much as possible. Uncap it, use it, cap it.
3. Wipe the nozzle before capping. Residue on the tip cures, blocks the nozzle, and can glue the cap shut.
4. Keep it in its original bottle. Manufacturer packaging is designed to keep moisture out. Transferred glue loses that protection.
5. Store it upright and out of direct sunlight. Upright keeps glue off the nozzle and cap threads, and UV degrades cyanoacrylate over time.

No. It cures. Cyanoacrylate polymerizes on contact with moisture, so a bottle that has hardened has reacted with humidity that got inside. Nothing has evaporated.

It isn't underfilled. The headspace is there so the bottle can be squeezed, and so a layer of dry air separates the glue from outside air.

No. That removes the dry-air buffer protecting the glue and makes the bottle harder to dispense from.