It’s easy to remove a glass stopper that is stuck in a decanter or piece of chemistry glassware. The technique you choose depends on how important the contents of the container are to you. Also, for lab glassware, use caution with certain chemicals. Here’s what you do.
Best Method to Remove a Glass Stopper
Remove a glass stopper by following all of these instruction or just apply a few methods.
- Apply a few drops of penetrating oil to the joint where the stopper and the glassware meet. Options include WD-40 or a homemade version using vegetable oil and acetone (90% oil and 10% acetone). The oil needs time to navigate the glass, so allow a few hours to overnight.
- Soak the glassware and stopper in hot water.
- Remove the item from the water. Place an ice cube on the stopper. You can use an inverted paper cup to hold it in place. Meanwhile, wrap a hot towel around the bottle neck.
- Remove the towel and gently tap around the bottle neck using a wooden spoon. Use wood because it won’t mar the glass (not metal).
- Remove the stopper.
- Repeat the process if necessary.
A vibrating appliance, such as an electric razor, offers an alternative to the wooden spoon. Turn on the razor and press the body of the device (not the shaving part) against the bottle neck. Work your way around the stopper and then attempt removal.
How to Remove a Glass Stopper When the Contents Matter
For decanters and certain chemicals, preserving the quality of the container contents matters. Avoid heating the entire container or applying penetrating oil, which could contaminate the contents.
- Wrap a heated towel around the container neck.
- Place an ice cube on top of the stopper.
- Allow a few minutes, so the bottle neck gets warm and the stopper gets cold.
- Tap around the bottle neck using a wooden spoon.
How Removing a Glass Stopper Works
So, there are a couple of different principles at work here. Applying heat to the decanter or bottle serves two purposes. First, thermal expansion slightly loosens the grip of the glassware neck around the stopper. Meanwhile, chilling the stopper shrinks it a tiny bit. This may be all you need for freeing the stopper.
Heating the decanter or bottle also changes the pressure inside the container. Sometimes a partial vacuum inside the container compared to outside air holds the stopper in place. When you warm the glassware, its contents try to expand, generating positive pressure.
Tapping the bottle neck with a wooden spoon gently breaks adhesions holding the stopper inside the container. This can be as simple as knocking tiny bits of sintered glass free from each other. Glass is silicon dioxide, so it also responds to sudden pressure electrically.
Applying penetrating oil works because the fluid seeps into tiny openings between the stopper and the glassware. The oil lubricates the joint and its solvent dissolves some chemicals that may stick glass together.
Use Caution With Chemistry Glassware
Lab glassware poses a couple of extra challenges that you don’t get with a decanter in your home. Use precautions removing stoppers from unlabeled containers. Wrap them in a cloth in case of breakage. Ideally, tap the bottle neck from a distance, perhaps using a wooden meter stick.
- Beware chemicals, such as picric acid, which form explosive crystals. Search YouTube for videos of what can happen.
- Strong bases can fuse the glass stopper and the glassware. This makes removal much more difficult.
- Borosilicate glass becomes prone to thermal shock as it ages. The risk of glassware breakage is high if you apply heat and cold to old glass. Try penetrating oil and tapping first.
Have you removed a stuck stopper? What technique did you use?