how to make car diffusers

How to Make a Car Diffuser with Fragrance Oil - Step by Step

Car diffusers are super easy to make. All you need to do is combine some fragrance oil with our Reed Diffuser Base and pour the mixture into a car diffuser bottle. It’s really that easy! If you’ve been meaning to try this project but aren’t sure where to start, follow this easy tutorial.

Watch a quick video of this project!

Step 1: Choose a Fragrance Oil

You can use any fragrance oil or essential oil that you want when making a car diffuser. Technically, car diffusers fall under category 10A on an IFRA statement. However, this category relates more to regular reed diffusers, which have IFRA limits because the scented oil may come in contact with your skin when flipping the reeds. However, there isn’t really a situation where you would end up touching car diffuser oil because of how the bottles are designed.

Step 2: Determine Fragrance Load

Although you don’t need to worry so much about the IFRA for car diffusers, you do need to keep diffuser oil ratios in mind. Our Reed Diffuser Base can hold up to 50% fragrance oil by weight. This means that fragrance can make up no more than 50% of your recipe. For car diffusers, a good fragrance load is anywhere between 10-25% fragrance.

Step 3: Calculate Ingredients

Our car diffuser bottles can comfortably hold 7-8 ml of liquid. To determine how much fragrance and diffuser base you need, you will need to know the fragrance load and the number of bottles.

If I want to make one car diffuser bottle with a 25% fragrance load, I will need 2 ml of fragrance and 6 ml of diffuser base. If I wanted to make 6 diffuser bottles with a 25% fragrance load, I would need 12 ml of fragrance and 36 ml of diffuser base.

Step 4: Gather Supplies

Other than fragrance oil and reed diffuser base, you will need car diffuser bottles, a pipette, and a mixing container. Our 3 oz measuring cups work great for mixing small batches of car diffuser oil because they have a spout for pouring. For larger batches, you can use a funnel pitcher to mix your ingredients instead.

We also recommend wearing nitrile gloves whenever making a project with fragrance oils. If you are making a large batch of diffuser bottles at once, it will be easier to measure the ingredients by weight. We recommend using a digital scale for large batches.

Step 5: Mix Ingredients

Next, you will simply combine your fragrance oil and reed diffuser base in a mixing cup. When making a small batch, the easiest way to measure ingredients is with a pipette. Use the pipette to transfer the fragrance and diffuser base to your measuring cup. For example, if I’m making just one diffuser bottle with a 25% fragrance load, I will use a pipette to transfer 2 ml of fragrance and 6 ml of diffuser base to a mixing cup.

If making a large batch, place your measuring cup on a digital scale and tare it to zero. Then pour the required amount of fragrance oil and diffuser base into the measuring cup.

Step 6: Fill the Car Diffuser Bottles

Next, remove the wood lids and plastic stoppers from your car diffuser bottles. Then use a pipette to transfer 7-8 ml of oil to your car diffuser bottle(s). Alternatively, you can use the spout on our 3 oz measuring cups to pour the oil directly into the bottle. Be sure to leave a little room at the top instead of filling them completely full. This gives you room for the plastic stopper to be put back in.

Step 6: Packaging and Using Your Car Diffusers

If you want to store your car diffusers for later or you plan on selling or gifting them, be sure to put the plastic stoppers back in the bottles before putting the wood lid back on. The stoppers keep your oil from spilling and will keep the diffusers smelling fresh.

If you want to use your car diffuser right away, you can leave the plastic stoppers off. It’s a good idea to save the stopper in case you want to store the diffuser bottle later.

When you’re ready to use the car diffuser, remove the plastic stopper and place the wood lid onto the bottle. Next, tip the bottle upside down for 5-10 seconds, which allows the oil to soak into the lid. Finally, turn the bottle right side up and hang it in your desired location.

Find some great tips in our blog about Using Car Diffuser Bottles

When in use, some people prefer to keep the plastic stopper in the bottle, while others don’t use the stoppers at all. If your bottles will remain upright and aren’t at risk of tipping over, you don’t need to use the plastic stoppers. Keep in mind the oil will soak completely out if the bottle tips over and is left unattended. If you are selling or gifting these bottles, you definitely want to use the plastic stoppers to keep the oil from spilling.

When the scent needs to be refreshed, all you need to do is tip the bottle over again and let the oil soak into the lid for a few seconds. Make sure the plastic stopper is out first.

Did you make this project? Show us how it turned out by tagging us in your photos or using #MadeWithNorthWood on social media!

NorthWood is not responsible for the products you make with our supplies, ingredients, or informational resources. You are responsible for testing your end product for safety and compatibility. 

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