With the sharp rise in Coatings (ie Optimum Opti-Coat, 22ple, etc.) that require a properly prepped surface we have been receiving more questions about how you dilute isopropyl alcohol (aka IPA) correctly. One of the most popular bottles you can pick up contains a ratio of 70/30 (Alcohol to Distilled Water), which can make the math a bit challenging if you want to dilute it. While it is generally okay to use it at the 70/30 ratio, many detailers prefer to dilute it down to a 50/50 (Alcohol to Distilled Water) ratio for optimal results. If you don’t want the boring details skip to the pictures and chart at the end of the article. For those who want to know the exact math behind the dilution we did our best to break it down very simply so please keep reading.
Using the following formula, .7 represents the 70% isopropyl alcohol you have and .5 represents the 50% we want to end up with. Therefore our formula to determine the appropriate percentage of alcohol is:
.7x = .5 = .7143 or 71.43%
In conclusion x = 71.43 or 71.43%. So no matter what size bottle you have fill 71.43% of it with the 70/30 mix of isopropyl alcohol and the rest with water. If you want to determine the percentage of water just take the difference between the 71.43% and a full bottle which is represented by 1.
1 – .7143 = .2857 or 28.57%
Each bottle should then contain 28.57% distilled water no matter what size the bottle is. Below are the DI Accessories Isopropyl Alcohol and 2 bottle sizes of our DI Accessories Trigger Spray Bottles (22oz, and 32oz). Each bottle is marked with a black line to where this 28.57% of each bottle is located.
You are now going to want to fill each bottle to this line with water. We used some blue food coloring to help highlight the water for picture purposes.
After filling the bottle with 28.57% distilled water fill the rest of the bottle with a 70/30 isopropyl alcohol.
You now have a bottle of 50/50 isopropyl alcohol mix to help remove old protection and ensure you have a clean surface! You can also take a look at the table below for complete dilution information on multiple size bottles!
| Diluting Isopropyl Alcohol (70/30 to 50/50) | ||||
| Bottle Size | % Of Water (Distilled) | Ounces Of Water (Distilled) | % Of Isopropyl Alcohol (70/30) | Ounces Of Isopropyl Alcohol (70/30) |
| 8 Ounces | 28.57% | 2.3 Ounces | 71.43% | 5.7 Ounces |
| 12 Ounces | 28.57% | 3.4 Ounces | 71.43% | 8.6 Ounces |
| 16 Ounces | 28.57% | 4.6 Ounces | 71.43% | 11.4 Ounces |
| 22 Ounces | 28.57% | 6.3 Ounces | 71.43% | 15.7 Ounces |
| 32 Ounces | 28.57% | 9.1 Ounces | 71.43% | 22.9 Ounces |
| 64 Ounces | 28.57% | 18.3 Ounces | 71.43% | 45.7 Ounces |
| 128 Ounces | 28.57% | 36.6 Ounces | 71.43% | 91.4 Ounces |
Hopefully this information was helpful in answering some of your questions about diluting isopropyl alcohol!