Superglue or cyanoacrylate adhesive is a fast-acting adhesive that is commonly found in many households for minor repairs and craft projects. Its ability to bond almost instantly makes it very convenient to use. However, since superglue has a chemical composition, a common question is whether it has an expiry date or goes out of date.
What is superglue made of?
Superglue contains cyanoacrylate, an acrylic resin that hardens rapidly when it comes into contact with even weakly basic surfaces such as water or hydroxyl ions. This reaction causes the glue to cure and bond two surfaces together.
Some common ingredients in superglue include:
- Ethyl cyanoacrylate – the main acrylic resin
- Methyl methacrylate – helps control setting speed
- Polymethyl methacrylate – thickens the glue
- Hydroquinone – prevents early polymerization
- Filler materials like clay, silica or fumed silica
Apart from these chemical ingredients, superglue may also contain colorants and fragrances. The exact composition can vary across different brands and manufacturers.
Does superglue expire?
Yes, superglue does have an expiry date and can expire over time. Here are some key factors that cause superglue to go out of date:
- Loss of moisture: Exposure to air causes superglue to lose moisture over time. Since moisture initiates the curing process, loss of moisture will prevent the glue from setting and bonding properly.
- Loss of reactivity: The cyanoacrylate resins in superglue can lose their reactivity over time with prolonged storage. This leads to reduced bond strength and performance.
- Separation: The ingredients in superglue may separate when stored for too long. This can lead to inconsistent results.
- Hardening of glue: As the moisture evaporates over time, the glue can thicken and harden in the bottle before use.
How long does superglue last?
An unopened bottle of superglue will generally last 12-18 months from the date of manufacture if stored properly. However, once opened, the shelf life is reduced to around 6 to 12 months. This timeline can vary based on these factors:
- Storage conditions – Superglue stored in a cool, dry place away from direct light will last longer than if stored in hot, humid or bright conditions. Refrigeration can help prolong shelf life of opened glue.
- Frequency of use – Frequent opening exposes the glue to air and moisture leading to faster drying out.
- Bottle size – Smaller bottles get used up quicker than larger bottles which take longer to expire once opened.
- Brand and formula – Certain brand formulations are designed to resist humidity and have longer shelf lives.
As a rule of thumb, an unopened superglue stored properly can last around 1-2 years from date of purchase before expiry. Once opened, expect around 6 months to a year before the glue no longer works optimally.
How to tell if superglue has expired?
Here are some simple ways to test if your opened bottle of superglue has expired and gone bad:
- Consistency – Expired glue will become thicker and may not flow easily. Fresh superglue has a consistency like that of oil.
- Color – Old superglue may turn cloudy or yellowish. Good quality glue is normally clear.
- Bonding – Try applying a small amount to join two items. Expired glue will take much longer to set and may not create a strong bond.
- Smell – Old superglue will have an odd, sour chemical smell compared to the sharp, irritating odor of fresh glue.
You can also check the expiration or ‘best before’ date printed on the bottle. However, if properly stored, most cyanoacrylate superglues remain usable for a few months beyond this date.
Does expired superglue still work?
In most cases, expired cyanoacrylate superglue will still work to some extent past its expiry date, but its effectiveness and strength will be reduced.
As moisture evaporates from the bottle, the superglue thickens. You may be able to salvage thickened glue by adding a drop or two of water. This rehydrates the cyanoacrylate and makes the glue usable for a short while.
However, rehydrating old superglue only provides a temporary fix. The ability of the cyanoacrylate resins to bond degrades over time. This means expired glue even if rehydrated will only have a fraction of the original bond strength when fresh.
For small basic repairs, revived superglue may hold. But for most applications, it is better to use a new bottle once opened glue is past 6-12 months. The bonding capacity deteriorates gradually, so expired glue may hold at first but the bond is likely to fail over time.
Can you use superglue after expiry date?
It’s not advisable to use superglue that is many years past its printed expiry date. In this case, it simply won’t work well at all.
However, if your superglue bottle has been opened for less than 2 years, you may be able to use it past the expiry date if:
- It has been stored properly in a cool, dry location.
- The glue still flows evenly and is relatively clear.
- A small test application shows it can still bond well.
- You only need it for minor arts, crafts or repairs where bond strength is not critical.
Avoid using expired superglue for any heavy duty application where the hold needs to be very strong and durable. The adhesive strength will be lower and risk of joint failure higher.
Check the condition of old superglue before applying to any important items or surfaces. And re-glue joints if necessary using fresh glue.
How to store superglue properly?
To get the full shelf life out of your super glue, follow these tips for proper storage:
- Keep unused superglue in a dry, cool place away from direct light and heat. A larder, cupboard or drawer works well.
- Refrigeration can help prolong the shelf life of opened bottles by slowing moisture loss. Let refrigerated glue come to room temperature before use.
- Ensure the bottle cap is tight after every use to limit air exposure. Or transfer to a smaller air-tight container.
- Store glue in upright position to keep moisture in the bottom of the bottle.
- Avoid drastic temperature fluctuations which can cause moisture condensation in the bottle.
- Keep away from humidity and moisture to prevent hardening.
- Always check the expiry date and condition before purchasing superglue.
Following the manufacturer’s storage instructions is also recommended for maximum shelf life. Take care to keep superglue out of reach of children.
Disposal of expired superglue
Out of date cyanoacrylate glue where the ingredients have degraded should be disposed of properly. Here are some tips for safe disposal of expired superglue:
- Allow glue to fully harden by leaving the opened container in a well-ventilated area. The fumes released as superglue cures can be irritating.
- Once fully hardened, the glue can be disposed of in the waste bin as solid waste.
- Pouring small amounts of expired liquid glue directly into the garbage is also an option. Avoid pouring down the drain.
- Check if your local community waste management offers toxic disposal days where household hazardous chemicals are accepted.
- You may be able to dry out and absorb liquid superglue with cat litter or sawdust before throwing into garbage.
- Never try to burn or ignite old superglue as it can release toxic fumes.
Disposal laws vary, so check regional regulations about correct disposal procedures. Call your local waste authorities if you need guidance about disposing of larger amounts of expired superglue or other hazardous adhesives.
Can expired superglue make you sick?
The cyanoacrylate fumes released as superglue cures can certainly irritate eyes, skin, and respiratory tracts in some individuals. However, fully cured and hardened superglue is generally considered non-toxic.
That said, degraded cyanoacrylate glue past its expiry may contain additional breakdown products or contaminants that could cause more severe reactions if ingested or exposed over long periods. Eye and skin irritation is still the most common health risk.
To be safe, its best to avoid using expired superglue, especially around food preparation. Dispose of outdated glue carefully using protective gloves and ventilation. Keep superglue containers away from children and pets at all times.
Consult a doctor if you experience significant eye, skin, breathing or digestive distress after using old superglue – this may indicate sensitization or chemical contamination of expired product.
Tips for using superglue safely
When using either fresh or expired superglue, keep these safety practices in mind:
- Always work in a well-ventilated area.
- Wear gloves and eye protection.
- Avoid fumes getting trapped under nose or mouth.
- Never use near open flames as fumes are flammable.
- Clean skin quickly with acetone nail polish remover if glue makes contact.
- Avoid contact with natural fabrics which can rapidly absorb glue and bond to skin.
- Never ingest super glue or use around food containers.
- Use minimal amounts and reseal container immediately when applying.
Practice safety, use within recommended time frames, and dispose of correctly when expired. This ensures superglue remains a useful adhesive without posing unnecessary health hazards.
Conclusion
Like any chemical product, cyanoacrylate superglue does have a limited shelf life and effectiveness period after manufacture. With proper storage, unopened superglue lasts around 12-18 months, while opened bottles are best used within 6-12 months.
Signs of expired superglue include thicker consistency, yellowish color, poor bonding ability and odd smell. While revived with water, expired glue has lower strength and is only useful for minor applications.
Discard outdated superglue via recommended hazardous waste disposal methods. Always use superglue with good ventilation and skin/eye protection. Though not acutely toxic once hardened, it’s still best to avoid using superglue long past its expiry date.