Of all of the products used in auto detailing, isopropyl alcohol might not even be on the radar. Also called isopropanol—or more commonly in the detailing world IPA—has its place in certain detailing applications.
In the first aid section, you’ll typically see isopropyl alcohol labeled as rubbing alcohol in concentrations ranging from 70% to 99%.
High concentrations of isopropyl alcohol can and will soften a vehicle’s clear coat with time. While it won’t instantly ruin a clear coat undiluted, it can be harsh. Always mix with water for best results. A 1/10 to 5/10 isopropyl alcohol to water ratio is a good starting point.
In this post, I’ll break down 5 ways you can use isopropyl alcohol to see better results when washing or detailing at home.
What does isopropyl alcohol do?
On a molecular level, isopropyl alcohol can remove non-polar compounds. Non-polar compounds include things like fats, oils, and gasoline.
You may already use rubbing alcohol as a household cleaner due to its cleaning properties (i.e. for cleaning grease spots on clothes) and it can also be used to remove smells.
Why is isopropyl alcohol used in detailing?
Some detailers and hobbyists use isopropyl alcohol because it removes substances not easily removed from a vehicle’s clear coat like dried-on wax, oils, and other difficult-to-remove substances.
What is an IPA wipedown?
An IPA wipedown is a term used in detailing that refers to using diluted isopropyl alcohol to remove substances from a vehicle’s clear coat prior to adding wax or protectant.
A spray bottle is typically used to apply the IPA solution in combination with a microfiber cloth.
Some detailers prefer commercial products for removing substances, while others swear by a simple IPA wipedown since it’s so cost-effective. Pure isopropyl has a pH of 6-7, so it’s a good idea to dilute it for best results.
Always dilute isopropyl alcohol in a spray bottle with distilled water. This ensures contaminants found in tap water won’t get mixed in.
Here are a few different ways to use isopropyl alcohol as part of your detailing regimen.
1. Removing wax or sealant from painted surfaces
The most common use of isopropyl alcohol is when wax or sealant needs to be removed from the car prior to compounding/polishing.
Some household products like dish liquid you can learn more about here do a pretty good job at removing wax on their own and are less aggressive, so you really don’t need isopropyl alcohol in many cases.
Trying to buff out a scratch? Applying an IPA wipedown will make it easier to see a scratch or blemish; scratches can be difficult when covered in wax!
2. Removing haze from a windshield, window, or mirror
Isopropyl alcohol can be a very effective way to clean up an oily or waxy windshield without applying products that just don’t work well. I used isopropyl alcohol the most on windshields, and it always does a great job.
Many detailing sprays that I have used (even on windshields) still leave streaks. Sometimes oil is hard to remove with a product like Invisible Glass. Isopropyl alcohol is great for cutting through leftover oils.
I wrote a post on how to remove haze from a windshield (and why it happens to begin with) you may want to check out.
When using isopropyl alcohol on windshields, just be careful not to get any on trim pieces as it may discolor them. I haven’t had this problem, but it’s worth paying attention to.
3. Removing sticker residue
Detailing a vehicle with an old bumper sticker or decal on the back glass? Try using isopropyl alcohol while you’re at it. Products like Goo-Gone work pretty well, but isopropyl alcohol can be effective if you don’t have a sticker remover handy.
I’ve found that it helps to let the alcohol penetrate into the pores of the paper, and it generally will come off.
Other products like Goof-off (not to be confused with Goo-gone) are a lot stronger and contain acetone, which will strip paint off from not-clear coated surfaces, and any rubber or vinyl surface. Isopropyl alcohol is much safer.
4. Headlight lens restoration
If performing a headlight lens restoration, isopropyl alcohol is a good product to use in-between stages. Starting with 300-400 grit sandpaper, dried on UV coating will begin to come off, leaving dusty, white chalk on the lens.
Between stages and at the very end of the sanding process, simply spray the surface with isopropyl alcohol and you’re good to go.
Again, alcohol can act as a strong cleaning agent, and many products on the shelf contain isopropyl alcohol at different concentrations.
If you’re looking to clear up your hazy headlights view my tutorial here.
5. Removing polish residue
As with headlights, another good use for isopropyl alcohol is for removing polish. As an example, once polish is applied after compounding to remove a white scratch, the surface may appear to be blemish-free if the polish is hiding the scratch in any way.
With a quick IPA wipedown, you can get a better estimation of what exactly the final result is. I’ve found when using some over-the-counter ‘polishes’ like Scratch Doctor, scratches seem to disappear until several weeks later when the polish begins to wear off.
A drop or two of an IPA solution is an easy way to check to see that your compounding and polishing really did remove the scratch.
Can isopropyl alcohol damage paint?
When mixed with water at the proper ratio, isopropyl alcohol is typically fine for vehicles so long as they are used properly. Over time, can 70-80% concentrations soften the clear coat? Yes, but a lot of products can do this when used improperly.
If you’re a little fuzzy on some of the terminology and products used to protect clear coats (like waxes, coatings, etc.), check out this article I wrote: Compound vs Clay, Polish & Glaze! 7 Products to Understand.
Stay away from applying any IPA to any freshly painted surface or for those with no clear coat (older vehicles). This can cause swelling or soften the clear coat.
When diluted with water, the risks decrease significantly, and the impact of diluted isopropyl alcohol (on occasion) won’t hurt anything.
However, if you are prepping a vehicle for paint, there are better solutions than isopropyl alcohol.
When not to use isopropyl alcohol on a vehicle
If painting a vehicle, you’re better off using a professional product like Prep-all or Blackfire Crystal Coat Paint Prep instead of isopropyl alcohol.
Isopropyl alcohol evaporates quickly and doesn’t contain a surfactant; surfactants will reduce drag.
Some people will use water plus a surfactant with their IPA mixtures. Water provides some lubrication, but it’s really not meant to be a paint prep.
Tips for using isopropyl alcohol in detailing
To recap, here are some tips for using isopropyl alcohol safely on your vehicle.
- Always dilute isopropyl alcohol. A 1/10 isopropyl alcohol to water ratio is a good starting point. Undiluted isopropyl alcohol can eat away at your clear coat over time.
- The softer the clear coat the lower the percentage you should use.
- Use isopropyl alcohol on an as-needed basis…not after every wash
- No need to apply any pressure to painted surfaces – the alcohol will do the work
- The alcohol percentage you purchase does not matter as long as you dilute it correctly.
- Purchase a spray bottle and distilled water to use with the alcohol
- If concerned about your current clear coat levels, check out this video on YouTube for tips on measuring it.
In general, thousands of people use isopropyl alcohol in some way or another, although there are some that prefer not to ever use it on paint.
How do you feel about isopropyl alcohol in detailing? Leave a comment and let me know anything I missed or anything you’d like to add :)
This post was updated on January 3, 2023 to reflect industry best practices.