Every woodworker handles wood glue daily as it is an essential aspect of the job. You tend to store various types of wood glue in your woodworking workshop. As you use only a small quantity for each use, you may wonder how long you can keep wood glue before it expires.
Does wood glue go bad or expire? Yes, it does. Wood glue comes in many types and compositions. The duration of the effectiveness of each type may vary. But generally, if you store it properly, wood glue can last up to three years for at least polyurethane and PVA glues.
Incorrect storage of wood glue can result in its rapid deterioration. The obvious solution to making your wood glue last longer is to keep the container of the lid tightly closed. You should also prevent your glue from exposure to direct sunlight.
Keep wood glue within the temperature recommended by the manufacturer. For example, if you allow PVA glue to freeze and thaw repeatedly, it will be well below the recommended temperature. The glue will thicken and eventually become unusable.
Wood Glue Expiry Date
You might not want to take chances by consuming edible products that have crossed the expiry date. You would probably discard such products. With wood glue, however, the case is different.
Some glue manufacturers provide an expiry date to limit liability in case incorrect storage results in product failure. But mostly, you may not see an expiry date – only the date of manufacture.
Normally, the official shelf life printed on the label is one or two years. But if stored correctly, you can use the product for much more time. There have been cases where white or yellow glue lasted for over 10 years.
How to Know That Glue Has Gone Bad
The viscosity level of glue is the best visual indicator that wood glue has gone bad. The glue should pour well. If it doesn’t, you can shake the container vigorously to make it pour.
In case of water-based glue that is too thick, you can dilute it with water. If your glue is still thick and resists sticking to wood, then it is time to buy some new wood glue. Another major indication of expired glue is a color change.
If you doubt that wood glue has gone bad, do not attempt to use it. You could spoil a perfectly good project by trying to save a few dollars on the glue.
How to Locate the Expiry Date of Wood Glue
The typical shelf life for household glues is several years. But many manufacturers don’t print an expiry date. However, you will usually see a manufacturing date, which can at least tell you how old the glue is.
Also, even the manufacturing date might be in code, as a part of a long number. In such a case, you could visit the manufacturer’s website to locate the date and number within the coded number on the label.
What to Do in Case of Expired Wood Glue
Wood glue like most other products has an expiry date. Glues made of organic extracts like protein or gelatin which are water-based can develop mold after expiry. They will become unusable.
When you notice mold on your glue, you might be tempted to try to use it one last time. But this is not recommended. You may end up ruining your substrate, and it could spoil your project.
Moreover, wood glue that has passed the expiry date may not bond well with new glue. In such a case the best remedy is to discard the expired glue. Ensure that you properly dispose of the glue and do not pollute the environment.
Expired Natural Glue
You can check the label, which will have the manufacture date if not the expiry date. If you have opened a natural glue container, ensure to use it within the recommended time which is normally one year for natural glue.
If you store your glue in a cool, dry place but prevent it from freezing, it may last a little longer. But if you see signs of mold or color change, then is time to replace it.
Expired Liquid Glue
With liquid, water-based glues, you need to pay attention to the manufactured date. It is a common mistake to discard glue that was according to the label, manufactured over a year ago.
But the correct approach is to keep a note of the date you open the container. You can write the date on the label. A month or two after opening the glue container, your glue might deteriorate. But if you have stored it correctly, it might just last a bit longer than the expiry date provided by the manufacturer.
How to Dispose of Glues Correctly
You must dispose of all glues according to federal and local laws and ordinances. It is a good idea to check with your local authorities before tossing large quantities of glue into the trash or drains. Of course, small quantities may not attract much attention.
Although synthetic glues come under the category of toxic waste, natural glues are considered non-toxic and you can dispose of them normally.
In the case of synthetic waste glue, you can make it solid by mixing it with sawdust and then disposing of it. Alternatively, you can get absorbent waste disposal granules in the market, mix your waste glue with those and dispose of the resultant mass.
If you need to dispose of waste glue in bulk, whether synthetic or natural, you should avail of the services of a waste disposal company. Try as far as possible to recycle your glue packaging.
Shelf Life of Different Glues
Now that you have an idea of how glue can deteriorate after it crosses its expiry date, let’s compare the shelf life of different glues:
Comparison of Shelf Life of Different glues
|Glue Type||Typical Shelf Life (Before Opening)||Typical Shelf Life (After Opening)|
|PVA Glue||2 years||6 months|
|Cyanoacrylate Glue||1 year||2 months|
|Polyurethane Glue||1 – 2 years||1 year|
PVA Glue Shelf Life
PVA glue will last for about two years if sealed. After the expiry date, the following two things can happen to your PVA glue:
Hardens Inside the Container
If air enters the container, the product will harden especially after the expiry date. Even if you close the lid tightly, a tiny amount of air is enough to harden your glue. The entire contents become a solid block and the process is irreversible. The shelf life of PVA glue is up to six months after opening it.
Separates Inside the Container
If you leave your PVA glue container standing at one location without disturbing it and it isn’t exposed to air, this can happen. It separates the emulsion part (PVA) from the liquid part (typically water).
If you discover this happening early, you can restore the consistency of the glue by stirring it. You can filter off the solid parts that don’t get stirred. But once your PVA glue separates like this, it will not be as effective anymore.
Superglue Shelf Life
Cyanoacrylate that we also call superglue is an extremely reactive substance and challenging to store for long periods. The main culprit for superglue to deteriorate is atmospheric air. If it were possible for superglue to be stored devoid of air, it could last indefinitely.
So, air would be present in the container even fresh from the factory. Further, minute trace WILL penetrate the container over time. Once opened, the situation becomes even worse, and the glue will harden even more rapidly. In this light, the best approach to using superglue is to buy small quantities at a time.
Polyurethane Wood Glue Shelf Life
Polyurethane (PU) glue bears chemical similarities with cyanoacrylate glue. It also behaves similarly to superglue. But because PU glue is less reactive in the air than superglue, it has a relatively longer shelf life in an unopened container than cyanoacrylate wood glue.
You can prolong the life of PU glue by keeping it away from heat and light. From the above table, you can see that PU glue can last up to one year after opening the container and up to two years for a sealed container.
Tips on Prolonging the Life of Wood Glue
The best place to store wood glue is a dry, cool basement. The worst condition for storing wood glue is to let it freeze and then thaw out. Each freeze-thaw cycle gradually deteriorates the wood glue.
It forms gels that gradually become more difficult to disperse. Ultimately, you will be unable to break up these gels and the glue will solidify and become unusable. Heat also hastens the polymer to clump and form a gel.
To prevent the glue from deteriorating rapidly, or to at least delay the process, here are a few tips to follow:
- Don’t open your wood glue until you require it
- Keep wood glue away from moisture
- Avoid exposing wood glue to excess heat
- Prevent excessive exposure of wood glue to direct sunlight
Does wood glue go bad or expire? Yes, as we have revealed in this post, wood glue, like all other glues, begins to deteriorate as soon as you open the container. Different glues degrade differently, but eventually, no glue will last indefinitely, even in a sealed container.
We have provided you figures in the above table that gives you a rough estimate of the shelf life of various glues with and without opening them. You can take this information as a rule of thumb and apply it to any wood glue that you might be using. It will help you to get the best out of your wood glue, to make your gluing work in your woodworking projects easier and more efficient.