How To Make Your Acoustic Foam Expand Faster

Acoustic foam is made from various materialsOpens in a new tab., including polyurethane, polyester, and compressed wool, which are almost always compressed when shipped to you. The material’s expansion quality gives acoustic foam its sound-absorbing properties. However, the entire process often takes more time than anticipated.

You can make your acoustic foam expand faster by blowing over the material with a blast of hot air from your hairdryer. The expansion process only takes a couple of minutes. However, if you don’t have a hairdryer, you can soak it in warm water or simply wait 48 hours for it to expand.

In this article, I’ll give you some tips on making your acoustic foam expand faster so that you don’t have to wait an entire week for it to expand completely. Let’s get started!

How To Make Your Acoustic Foam Expand Faster

What Is Acoustic Foam?

Acoustic foam is a type of material that is used to absorb sound. It’s commonly used in recording studios, home theaters, and other spaces where sound quality is important. Acoustic foam is available in various shapes and sizes and can be cut to fit any space. It’s also relatively easy to install.

The Different Types of Acoustic Foam

There are various types of acoustic foamOpens in a new tab. on the market. Still, they can be broken down into two major categories: open and closed-cellOpens in a new tab.. As the name implies, an open-cell acoustic foam is made of a porous, open-cell structure that allows it to trap sound waves and prevent them from echoing. On the other hand, closed cell foam has more than half its cells not interconnected with each other.

Acoustic foam can also be classified by its material. On that note, polyurethane is the most commonly used material to make acoustic foam. Polyurethane foam is a type of acoustic foamOpens in a new tab. that’s commonly used in home and professional studios. It’s preferred for its ability to absorb high-frequency sounds bouncing off the wall. Acoustic foam also works for low-frequency sounds, provided that you use one of sufficient thickness.Opens in a new tab.

Another common material used in acoustic panelsOpens in a new tab. is compressed wool. Wool is a natural fiber that has been used for centuries. It’s durable, comfortable, and has many uses. It can be compressed into blocks of acoustic foam.

Ways To Make Acoustic Foam Expand Faster

If you recently bought acoustic foam, you may have noticed that it takes forever to expand. This can be a problem if you need to soundproof a large area quickly. And as promised, here are several ways to expand acoustic foam faster:

Gently Separate the Foam Pieces

This may sound obvious, but, when your foam panels come compressed, you must separate them and attempt to expand each panel. Taking the foam out of its sealed package exposes it to air and kickstarts the decompression process.

Compression is the process of reducing the volume of a material. When compression is applied to the acoustic foam for shipping, it affects the structure of the panels, which in turn affects their ability to absorb sound.

Separating the foam pieces also provides ample space for each piece to expand.

Use a Hairdryer To Speed Up the Expansion Process

If you’re rushing to use your acoustic foam, try using a hairdryer to speed up the expansion process. You can either blow warm air through the foam or use a cool air setting to speed things up.

The key to using a hairdryer to speed up the expansion process is not overheating the acoustic foam. If you do that, the acoustic foam could lose its effectiveness at soundproofing. Work from the outside edge of the foam inward when using a hairdryer to speed up the expansion process. This will help the foam to expand more evenly.

Soak the Foam in Warm Water

Heat favors expansion, as you may have witnessed in our previous step. If you don’t have a hairdryer, warm water works too. When the acoustic foam is soaked in hot water and dried, the tiny cells open up and expand faster than if left to sit for prolonged periods.

  1. Fill a bathtub or bucket with warm water. Make sure that the water is not so hot that it starts to boil.
  2. Place the foam inside and leave it there for a few minutes. 
  3. You may also want to keep squeezing the material in the water to expel tiny air bubbles.
  4. Letting the foam sit for a few minutes will help it fully expand.
  5. Wring the material and let it dry for 24 hours before installation.

When soaking the acoustic foam in hot water, be sure to keep a close eye on the water temperature. Ensure the water doesn’t get too hot, or it could damage the foam or cause burns.

Place the Acoustic Foam in a Warm Room

You can speed up the expansion by placing the acoustic foam in a warm environment. The room does not need to be an exact temperature. As long as it is warmer than your usual room temperature (68 degrees Fahrenheit or 20 degrees Celsius), you should notice that the foam expands more quickly.

It will take a few hours for the acoustic foam to expand completely, and during that time, the foam should be kept away from cold drafts.

If it helps, place the foam near a window that receives more sunlight to accelerate the expansion process. Sunlight is a good heat source and will help the foam expand more quickly. However, be sure not to leave the panels too long in direct sunlight.

Press Down on the Material To Make It Expand Faster

The most basic way to make foam expand faster is to apply force by squishing the foam material. As you press down on the foam, you increase the temperature of the material inside it. It is recommended to press down on the material with your hands.

You can also place the foam on a smooth-textured surface, like a table, and then squish it with your hands. Throughout the process, make sure to apply a consistent (but not excessive) amount of pressure.

Improve Circulation Around the Room

When you’re trying to make memory foam expand faster, it’s important to improve circulation around the room. Acoustic foam expands even faster when there is ample airflow. So, turn on your AC to ensure a nice cross breeze in the room. Additionally, make sure that the room has adequate ventilation so that the acoustic foam doesn’t trap any heat, dust, or allergens.

Try installing a ceiling fan in your recording studio. A ceiling fan will ventilate the room cheaply and efficiently.

Use a Hand-Held Steamer

You can make the memory foam expand faster by using a hand-held steamer. Hand-held steamers are used for the main purpose of removing wrinkles from clothing. There are many different types of steamers that you can use, including hand-held steamers, fabric steamers, and iron steamers. 

To use a steamer to expand the memory foam, place the latter on a smooth, non-porous surface, like a table. Then, use the hand-held steamer to apply steam to the foam. This will help the foam expand a little bit faster.

If none of these tips work, you can still get around by waiting a couple of hours. Sometimes, the acoustic foam could be over-compressed, which means it won’t expand as fast as you would hope. 

How Does Compression Affect Acoustic Foam?

Acoustic foam is made from polyurethane foam, which is a type of plastic. When it’s manufactured, it’s compressed into blocks or sheets. The thinner acoustic foam takes up less space than the thicker compressed acoustic foam, which makes it easier to transport and store.

However, this compression makes the foam stiffer, which makes it less efficient at absorbing sound. Compression also alters the material’s cell structure, which contains gasses and air that helps absorb reverberant sound energy.

If you think about it, there are several reasons why you should make your acoustic foam expand in the first place.

  • First, to reduce installation time: Installing compressed acoustic foam takes longer because you need to wait for its expansion. Besides, you need to use more of it.
  • Better sound control: Using more acoustic foam means that you’ll have less sound bouncing off the walls. This can greatly improve the quality of recordings in a studioOpens in a new tab. or make it easier to have a conversation in a room. 

Decompressing acoustic foam can also make it easier to install the foam. The material is more flexible when it’s not compressed.

How Long Does It Take Acoustic Foam To Expand?

Acoustic foam typically takes between 24 and 72 hours to expand to its full size. It may appear to be a finished product when first installed, but it needs time to stretch out and cover the surface it’s installed on.

Acoustic foam begins expanding as soon as it’s taken out of the vacuum seal and exposed to the air. However, the rate of the process depends on additional factors, including the surrounding temperature, thickness, and density.

Why Your Acoustic Foam Isn’t Expanding

Once your acoustic foam expands, it’s easy to work with. But sometimes, the foam expands very little or doesn’t expand at all. There are a few reasons why this might happen.

The Room Is Too Cold

Acoustic foam expands when exposed to heat, but if it’s stored in a cold environment, it won’t expand fast. It’s best to store acoustic foam in a warm environment, even if you’re not planning on using it soon. If you live in a consistently cold area, make sure to invest in a temperature control system (at least temporarily) to keep the storage space warm enough.

The Foam Was Stored Too Long

Acoustic foam manufactured for commercial use is only good for a certain period of time. If the foam was stored for too long, it might not be able to expand properly. If you purchased foam manufactured years ago and stayed compressed, it may be unable to expand as fast as you want it to.

The Foam Was Stored Incorrectly

In some cases, acoustic foam stored incorrectly may be unable to expand. The foam may not be able to breathe properly, which can lead to it becoming stale and unable to expand. The foam should be stored in a well-ventilated environment, preferably in a room where it’s not exposed to direct sunlight. 

The Foam Is Too Thick

If your acoustic foam is made too thick, it may not be able to expand fast. The extremely thick foam feels firmer due to more cells within its structure. More cells take more time to expand and fill up with air. That means more time to expand. Therefore, when choosing your panels, make sure to find an alternative that’s just thick enough.

The Foam Is Old

Old foam insulation won’t expand as fast as new foam. If the foam is more than a few years old, it may have lost some of its effectiveness. For better performance and less time waiting, you’ll want to use brand new foam. If you purchase used foam, now would be a great time to switch to the newest batch you can find.

The Foam Is of Poor Quality

If the acoustic foam you intend to use is of low quality, it may not be able to expand properly. Poor quality foam faces myriad issues, from poor performance, rapid wearing out, tears, and taking a long time to expand. If you notice that the foam is collapsing as soon as you open the bag or box, it’s probably not good quality. 

Make sure that the foam you buy has an STC ratingOpens in a new tab. of 29 or higher.

Defective Foam

Testing it is the best way to know for certain if your acoustic foam is defective. If the foam you bought is defective, you can return it or get a replacement from the manufacturer. You may be able to fix defective foam by rinsing it with water, drying it out, and then putting it back into the room.

If your acoustic foam isn’t expanding, you should be able to determine the reason by examining it.

Final Thoughts

Acoustic foam absorbs sound waves and prevents them from bouncing around the room, which can help to eliminate echo and improve the overall sound quality. Acoustic foam is effective at reducing noise, but it can take a long time to expand. If yours came in a super-compressed form in a vacuum-sealed bag, these tips should help you expand it faster.


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I'm Vinnie, and I'm here to support you to create your own studio at home, whether it’s for photography, recording audio, podcasts, or videos!

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