How To Make And Use A Still Air Box (SAB)

This guide will show you a DIY still air box for mycology enthusiasts wanting to up their game on a budget.

This is what the finished product will look like:

Why make a still air box?

A still air box is the most convenient way of upping your mycology game when it comes to working in a clean environment. This is because it allows you to create simple conditions free from air flow (hence the name “still air”). Halting air flow stops contaminants floating around and landing on your mycology work. Examples of times when a SAB is very useful include working with agar and making a spore syringe.

Regardless of whether you use a still air box you should always undertake mycology work in a draft free environment (close all windows and doors in the room you are working in before starting any mycology work that is at risk of contamination). By making a SAB yourself you will get the benefits of working in advantageous mycology conditions for a small outlay (about £25 or $30).

There has been many different ideas about what makes a good SAB over the years. Fortunately the simplest option is probably the best – namely cutting two holes in a storage container. There are a few ways of achieving this but the below method is the easiest I have come across. Some people may use a saw but in my experience it is likely you will crack the plastic and have to start again with a new container.

What materials do I need to make a still air box?

To make a still air box you will need the following:

A large transparent plastic storage container. I like my one which is 83 Litres/ 88 Quarts. You can go as big as you like. You can buy 3 from Argos for £50 and use the other 2 for actually storing things.
A metal tin that is between 5 and 6 inches in diameter. Make sure you remove everything from the tin like labels and glue. Also make sure your tin doesn’t have a liner on it that could melt upon heating.
A hob, either electric or gas, to put your tin on.
Some oven gloves to handle the hot tin.

How to make the DIY still air box

1) Mark Holes: First of all you need to mark where you want your holes to go for your arms. You need to allow enough space between the holes so that it is comfortable for you to put both your arms in at the same time. This will obviously be different for everybody but unless you are particularly big or petite I would do as follows:

I would leave about 9 inches between the holes from inside edge to inside edge.
I would leave about 5 inches from the the bottom of the container to the bottom edge of your arm hole as well.
To make life easier when you come to make your holes, draw around the tin with a marker pen so that you know exactly where you are putting the holes. As the tin will be hot, you don’t want to be messing around!

2) Prepare Tin: Make sure your tin is stripped back to the metal. You don’t want anything flammable on there. Before putting your tin on your hob, you need to make sure that all your windows are open and that you have plenty of fresh air flow. As you are going to be melting plastic you want to make sure you are NOT going to be breathing in any dangerous fumes.

Other considerations before you begin heating up your tin are:

Make sure you know where you will be putting the tin down once you have made the holes. I think the sink is a good option.
Get your storage box in position close to the heat source so that you can burn the holes without moving it around and as efficiently as possible.
Make sure you turn the heat source off before removing the tin. You don’t want to forget about it when you will be otherwise preoccupied.

3) Make Holes: Once you have everything in place it’s time to get your tin on the hob, top rim side down, and get the heat on. You will need to leave it for a bit (NOT UNATTENDED) so it gets nice and hot. Once your confident its really hot turn your heat source off, get your oven gloves on, and carefully remove the tin taking it from the base which should be furthest away from the heat. Place the rim of the tin gently on the first premarked hole and gently push down. The tin should pop through the storage box easily. Remove the tin to your safe place.

The plastic will probably have created a seal on the tin. To get it out you will have to use a sharp tool like a screw driver to poke through and prize it out. You may want to wait a bit for the tin to cool down. Once the plastic is out of the tin, check the tin to make sure there is no plastic residue melted on to it. As we are going to be repeating the process, you don’t want plastic on there that can re-melt on to your stove!

Once your confident the tin is clean it is time to repeat the process for the second hole.

And voila, you are now the proud owner of your very own DIY Still Air Box.

How to use your still air box

Here’s a basic guide on using a still air box:

Preparation:

1) Cleanliness: Ensure the still air box is clean and sanitized before use. Wipe down the interior surfaces with 70% isopropyl alcohol to create a sterile environment.

2) Materials: Gather all the necessary materials and equipment that you will be using when working inside the SAB. Wipe these down with 70% isopropyl alcohol where appropriate.

Operating the Still Air Box:

1) Setup: Place the materials you want to work with inside the box.

2) Gloves: Put your sterile gloves on. You can either use disposable sterile gloves each time (best option) or spray your gloves with, you guessed it, 70% isopropyl alcohol.

3) Minimize Air Disturbance: Try to minimize unnecessary movements or disturbances that could introduce contaminants. The idea is to maintain a “still” or as close to still as possible, environment within the box.

Once you’re finished working inside the SAB, carefully remove anything you have finished working with leaving nothing behind that could contaminate the environment.

What are the alternatives to a still air box?

The main alternative to using a still air box is using a laminar flow hood which looks like this:

You can buy a laminar flow hood such as this one from our good friends at Forefront Fungi. They range in price depending on the size but your looking at between £500 – £1000 ($600 – $1200) in most cases. We will hopefully be supplying these within the EU in the near future. You can also make these yourself but it is a bit more technical than making a still air box. Here is a good guide to take a look at:

A laminar flow hood operates by using high-efficiency particulate air (HEPA) filters to remove airborne contaminants from the air. Here’s a basic rundown of how it works:

Filtration: The hood contains HEPA filters that clean the incoming air by removing particles larger than a certain size (typically 0.3 micrometers) with a high degree of efficiency (usually 99.99%).
Airflow: Air is drawn through the HEPA filter and blown in a horizontal direction across the work surface.
Sterile Workspace: The filtered air creates a laminar, uni-directional flow of air that essentially sweeps away any contaminants present on the work surface, minimizing the chance of airborne particles coming into contact with the materials being handled.

Alternatively you could chance it using nothing and taking the aforementioned precaution of closing all windows/ doors in the room your working in. We would NOT recommend this!

Is it advantageous to use a flow hood over a still air box?

The short answer is yes. Although you can do a great job using a still air box (it helps teach you sanitary technique and good habits as well), the flow hood allows 99.99% of contaminants to be removed from the air flow.

The issue is if your sterility/ sanitary habits are poor and you introduce contaminants or create air flow by moving your hands too fast then a flow hood will not save you. The reality is for most beginner mycologoists the humble still air box is the best option. It costs far less and is a great learning tool that allows you to learn great technique. If you decide to get more involved in mycology then you can invest in a flow hood (or make one) further down the line and take everything you have learned from the SAB with you.

Happy Mushrooming!