How To Make A Soundproof Box Out Of Pallets

Soundproof boxes are very handy if you frequently rely on a noisy generator for power.

Unfortunately, soundproof boxes aren’t something that you can just pop into your local Walmart to buy. They are a very niche product, which is quite hard to find.

While there are plenty of guides online about how to build a soundproof box yourself, very few of them tell you how to do it using pallets.

The main expense when building a box is the wood; using pallets will save you considerable money.

What You Will Need:

To build a soundproof box from pallets, you will need:

4 Pallets – the number of pallets required may vary depending on the size of your generator.
8-foot 1×2 boards
1-inch nails
2-inch nails
Hammer
Saw
Tape measure
Acoustic Foam Mats
Mass Loaded vinyl
Industrial stapler & staples
2 x hinges
A toggle latch
Screws & screwdriver

Once you have assembled the necessary gear, take these steps to turn your pallet box into reality:

1. Measure Up

Generators can vary in size significantly depending on their power output.

You will need your box to have about 15cm/6 inches of space between the inner walls and the generator all the way around.

So add 30cm/12 inches to both the width and length of your generator.

Add 15cm/6 inches to the height.

Once you’ve got these measurements, you can work out exactly how many pallets you will need.

Most generators except small low powered domestic ones will probably require two pallets to make a box which is big enough (especially as we need to double up the wood..more on this later).

For the purposes of this article, we are going to build a box for a generator measuring 61cm/24” L x 45cm/18” W x 50 cm/19.5” H.

Our box will therefore measure 91cm/36” L x 75cm/29.5” W x 65cm/25.6” H.

2. Prepare The Pallets

First of all, you need to dismantle your pallets.

This can be a serious workout! Use a claw hammer to lever the boards apart.

Once the pallets are completely dismantled, use your claw hammer to remove each nail you can find from the pallets.

3. Cut Them To Size

The average pallet plank is around 8.9cm/3.5” wide.

As we are doubling up the wood for soundproofing purposes will need 28 x 36”/91cm planks cutting (30, if we’re sticking exactly to the measurements but cutting the height of the box down a bit, won’t have much impact on the performance and will save cutting a plank vertically in half).

These will cover the two long sides of the box.

We will then also need to cut 28 x 29.5”/75cm planks for the box’s shorter sides.

Finally, we need to cut 32 x 36”/91cm planks for the box’s base and lid.

4. Build The Frame

Now it’s time to build a basic frame to attach the panels to.

To make your frame, use the boards and cut them to size.

For the purposes of our box, we need to create a frame measuring 91cm/36” L x 75cm/29.5” W.

We will also need to cut wood to the same measurements for the top of the box and the lid.

So we will cut six lengths of 36” and six lengths of 29.5”.

Then nail them together to create three 36” x 29.5” rectangles.

Next, we need to cut four 24 ¾ inch pieces.

These should then be secured to the corners of the frame, creating what looks like a table.

Finally, nail the 2nd rectangle to the other end of the corner pieces to create a box.

5. Ventilation Shaft

If you are making a soundproof box for a generator, you must allow oxygen to get into the box, or your generator will choke as it needs oxygen for combustion.

Cutting a big hole in its side will completely defeat the purpose of trying to make it soundproof.

Instead, you can use a ducting pipe, which is soundproofed by building an air vent sound maze.

These are quite fiddly and time-consuming to make; however, if you are serious about soundproofing your generator, it is well worth it.

To make your ventilation pipe maze follow these steps:

Get a square ducting pipe (these are much easier to work with than round ones). The longer it is, the more effective it will be; however, you will need to reach into it to properly soundproof it, so don’t get one that is too long.
Get some 3mm acrylic sheets and some acoustic foam.
Cut the square ducting tape into a size and shape that will fill 70% of the duct.
Stick the acrylic foam onto both sides of the acrylic.
Fit the acrylic into the pipe, spaced out about every 15 cm. They should alternate with the first one being stuck to the bottom, the next being stuck to the top, etc.

This means that when soundwaves travel through the pipe, they will be deflected back. The foam will also help to absorb soundwaves and reduce echo and vibration within the pipe.

6. Fit The Panels

Now it’s time to fit the pallet panels onto the frame.

Before nailing them in, lay them out correctly, then nail the second layer of planks over them, making sure to cover the gaps between each plank. This will help further soundproof the box when it is finished.

You will need to cut the ends of the overlapping planks to make it fit.

Once you have done this for each of the side panels, nail them onto the frame, don’t forget to do the same for the lid.

7. Add Mass Loaded Vinyl

Adding mass loaded vinyl is a great way of further deadening and soundproofing your box.

Staple this inside the interior of your box, covering all surfaces.

8. Cut The Acoustic Foam To Size

Measure up the inside of the box and cut out your acoustic foam to fit, ensuring that this is sufficient foam to thoroughly cover all surfaces.

9. Glue In The Foam

This is simple enough, get some glue (green glue is optimal for soundproofing jobs, but any will work fine) and cover the inside of the box and the inside of the lid in it and get your acoustic foam attached.

10. Fit The Air Vent And Wire Holes

To fit the air vent, you first need to know where your generator is drawing air from. Please place it in the box and work out where best to position the pipe to ensure that the generator will get sufficient air.

Measure your pipe up and carefully cut out the area. The hole should be as tight as possible to minimize noise transfer.

Fit your pipe into the hole and seal it using liberal applications of green glue to ensure the gap around the pipe is fully sealed.

Use any leftover bits of acoustic foam to stick around the inside of the whole opening inside the box.

Then follow the same process again to create and seal holes for any generator wires to go in.

When feeding your wires through the hole, wrap them tightly in acoustic foam to better fill the hole more completely.

11. Fit The Lid And Seal The Opening

Fit the hinges to the lid and then put two rows of weather stripping inside the box lid all around the edge of the opening so that when the lid is closed, it compresses the weather stripping creating a tight soundproof seal.

12. Fit The Clasp

When the lid is closed, it’s important that it closes tightly to create a solid seal all the way around the perimeter of the box opening so that sound doesn’t leak out of it easily.

Therefore, you should fit the clasp at a distance, which makes it slightly difficult to close due to the clasp’s tightness.

This will ensure that the weather stripping is well compressed, making an air-tight seal around the perimeter of the box opening.