How Strong is Hot Glue – What it Can Stick to and What Not?

Hot glue is a type of adhesive commonly made from melted polymers, resins, and waxes.

The melted materials are turned into sticks that can be used with a hot glue gun. Once inserted and melted, the glue is dispensed through the gun’s nozzle and applied to a surface where it eventually cools and forms a long-lasting bond.

You can use hot glue for both porous and non-porous materials to get a long-lasting bond, particularly for applications where epoxy is not a viable option. The glue, when applied to the surface, dries quickly, and the strength of the bond created will likely be much stronger and permanent if the surfaces are slightly roughened before application.

That said, hot glue is not as strong as many other types of adhesives, like epoxy and CA glue. But it is still quite sturdy and can be used for a variety of small arts, crafts, and DIY projects. You can even buy it in different colors to add an extra element of fun to your projects.

What are Some Uses for Hot Glue?

Hot glue can be used for a variety of purposes, both practical and decorative, such as making handmade jewelry, and ornaments, scrapbooking embellishments, attaching decorations to surfaces, repairing broken items, and creating model structures.

Hot glue can also be used to temporarily repair clothing or other fabric items, including leather – it’s a helpful solution if you need a quick fix for a ripped seam or a loose button.

You can even use hot glue on painted walls for sticking up pictures or other wooden decorations like cardboard photo frames. And if needed, you can paint over it with regular acrylic or latex paint. 

Furthermore, hot glue can also be applied to finished wood furniture, although it is always best to test the glue on a small area first to ensure it will not damage the wood finish or surface.

How long does the glue last?

Hot glue is a type of adhesive. So it will last as long as most other adhesives.

In general, adhesives can typically last for two years if stored in a cool, dry place. However, in extreme temperatures, hot glue may lose its stickiness.

To guarantee the best outcomes, it’s advisable to use hot glue within one year of purchase if you live in a place with very hot or cold weather.

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What Will Hot Glue Generally Not Stick to?

Hot glue (or hot melt) can be used on various materials, including paper, fabric, wood, and plastic. However, there are some materials that it will not stick to. These include smooth surfaces like metal, silicone, vinyl, wax, and greasy wet surfaces.

Also, remember that hot glue is not designed for high-strength applications like gluing stones, rocks, granite, or steel together. You must use a stronger adhesive, such as epoxy or CA glue, for these projects. This also means that the maximum weight it can support is determined by the substance and glue used.

You should also avoid using hot glue in extremely cold or hot environments. The glue can become too soft at high temperatures and lose its bonding strength, whereas, at very low temperatures, it may become brittle and crack. A silicone sealant is a suitable alternative if you need highly durable glue that works well in cold temperatures.

Still, if you are unsure whether the hot glue will stick to a particular material, testing it on a small area first is better. This will help avoid any frustrating accidents later on.

Will hot glue work on aluminum?

Hot glue will not stick very well to aluminum surfaces like window frames or pipes because they are too smooth. However, you might be able to get it to stick if you roughen the surface first.

In general, lightweight aluminum foils can be glued using hot glue, but for heavy aluminum objects or smooth surfaces that are under load, it is best to use stronger adhesives like epoxy. Hot glue will not likely hold very well for long periods of time in these situations.

Can you use a hot glue gun on the glass?

Hot glue does not hold well on glass surfaces like drinking glasses, vases, sea glasses, or other decorative glass ornaments. Using it on such surfaces can break the glass or leave behind a sticky residue that is difficult to remove.

If you need to stick something onto a glass surface, consider using double-sided tape or silicone adhesive, which can be purchased online or at nearby hardware or craft stores.

If you don’t have the mentioned alternatives and must use hot glue, it’s best to lightly sand the glass surface first (using fine-grit sandpaper) to give the adhesive a better grip and prevent it from slipping and sliding off.

Also, make sure you set the temperature of your hot glue machine to low (between 250° and 270° Fahrenheit) before using it on glass. If it’s set too high, it could cause the glass to crack or shatter.

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How Long Does it Take for Hot Glue to Dry on Surface?

Hot glue is a fast-drying adhesive, which means it sets quickly. On average, it will take about 2 to 3 minutes to set on most surfaces.

However, the length of time it takes for the glue to dry can vary depending on the type/brand of adhesive and the surface on which you are using it. For example, Gorilla Hot Glue Sticks take about 30 to 60 seconds to set, while Loctite Hot Glue Sticks take about 10 seconds to set on paper.

It, therefore, is recommended to read the instructions on your hot glue gun sticks to find out how long you should wait for the glue to dry.

While it may attach the lighter surfaces like foil or paper fast, if you plan to set two extremely hard or heavy pieces together, it’s best to leave the surfaces pressed for about 2 to 3 hours to allow the bond to set.

What Temperature Can Hot Glue Withstand (Safety Tips when Working)

Most hot melt adhesives will start to liquefy at higher temperatures of about 250 °Fahrenheit and should be operated at or around 260 °F (130 °C) for a stronger bond and effectiveness.

It is important to note that as the temperature increases, the hot melt glue becomes less sticky and will take longer to set. Also, if it’s too cold, the glue might set faster, even before the substrates are bonded together, leading to a much weaker bond than expected.

If you are working with hot glue on a project exposed to extremely low or high temperatures, you might consider using different products like silicone adhesive or a two-part epoxy adhesive that will provide better results.

Safety Tips

Hot glue guns and sticks can get very hot, so taking some basic safety precautions when using them is essential.

• First and foremost, always read the instructions with your hot glue gun before using it.
• Wear protective gear like safety glasses and non-flammable gloves when handling hot melt glue. Also, keep it away from children and pets, as they could get injured by the hot glue.
• If you accidentally get hot glue on your skin, immediately cool the area with cold water. Then, use a cotton swab soaked in acetone nail polish remover and gently rub it off to remove any remaining glue.
• Never leave your hot glue gun unattended or plugged in for extended periods of time. Unplug it immediately after you’re done using it, and store the glue stick in a cool, dry place.

Remember that, unlike many industrial-strength glues, hot melt glue is not toxic as it’s made from thermoplastic polymers that do not emit harmful fumes.

But it can still pose a danger if inhaled, especially to those with respiratory conditions. Therefore, working in a well-ventilated area is essential to prevent any harm.

The Bottom Line

Hot melt glue becomes liquid when melted and solidifies quickly as it cools. It’s an excellent solution for a wide variety of quick adhesion projects like arts and crafts or temporary repairs.

However, you must note that this fast-setting adhesive will not stick to smooth surfaces like metal, silicone, vinyl, wax, or greasy and wet surfaces. It is also unsuitable for use in extreme temperatures and will not hold for long on heavy surfaces under force.

No matter the project, it is better to test the adhesive on a small area first to ensure it sticks before moving ahead. And always be sure to use the hot glue gun in a safe and well-ventilated area with protective gear.