[Mike Phillips]

How to Mix IPA for Inspecting Correction Results

WARNING
Do not chemically strip FRESH PAINT. Fresh paint has not fully cross-linked, dried and hardened. Introducing any type of solvent to the surface and allowing it to dwell could have a negative effect on the paint.

Note: The below article is NOT an official recommendation by Mike Phillips or Autogeek. It is an attempt to clear up any confusion on the topic of chemically stripping paint with the common products used for this procedure as discussed on detailing discussion forums. If you choose to chemically strip your car's paint, or your customer's car paint, all the risk is yours. Anytime you use a new product or procedure, it's a great idea to first test in an inconspicuous area and check the results before moving forward.

Common, easily found options for Isopropyl Alcohol also called IPA

How to Mix IPA for Inspecting Correction Results

Here are the easiest ways to mix an approximate 10% solution for the most popular concentrations of Isopropyl Alcohol available at the retail level.

91% IPA
To mix a 32 ounce Spray Bottle
Pour 4 ounces or ¼ of a 16 ounce bottle of 91% IPA into a 32 ounce spray bottle and top the rest of the bottle off with water. This will make 32 ounces at 11.375% IPA to Water solution.

70% IPA
To mix a 32 ounce Spray Bottle
8 ounces (or ½ of a 16 ounce bottle) will make 32 ounce of 17.5% IPA to Water solution. Get a 32 ounce container, pour in 8 ounces, (or ½ of a 16 ounce bottle) of the 70% IPA and then fill the rest of the container up with water and you get 32 ounces of 17.5% IPA to Water solution.

50% IPA
To mix a 32 ounce Spray Bottle
8 ounces, (or ½ of a 16 ounce bottle) will make 32 ounces of 12.5% IPA to Water solution. Get a 32 ounce container and pour in 8 ounces, (or ½ of a 16 ounce bottle) of the 50% IPA then fill the container up with water and you get 32 ounces of 12.5% solution.

Why dilute concentrated IPA to an approximate 10% IPA to Water Solution
The most common dilution levels you can purchase over the counter are 70% and 91% Isopropyl Alcohol, sometimes you can find 50% version. At the time I'm writing this article, there are no other articles on this topic to give people a general guideline as to how to dilute and use Isopropyl Alcohol to chemically strip paint. I actually made a post to an AG forum thread where I encouraged someone else to write this article, but to date there's been no takers, so here's my offering.

Most of what I've read are forum members recommending one of two options,

• Dilute IPA by 50% with water or 1:1
• Use it straight out of the bottle

Most recommendations I've read are:

Dilute IPA by 50% with water or 1:1

• Diluting 91% IPA 1:1 or by 50% with water would give you approximately a 45% dilution of IPA to water solution.

• Diluting 70% IPA 1:1 or by 50% with water would give you approximately a 35% dilution of IPA to water solution.

• Diluting 50% IPA 1:1 or by 50% with water would give you approximately a 25% dilution of IPA to water solution.

After talking to my chemist friends, they all felt that these dilution levels were overkill and too strong for removing residues after compounding and/or polishing paint. Most quality name brand compounds and polishes are water soluble and don't need a strong solution of Isopropyl Alcohol to dissolve, emulsify and loosen any leftover residues on the surface.

Their recommendation was for approximately a 10% dilution of IPA to water solution. The reason for this recommendation besides their chemistry background, is that a strong solution of IPA can stain and even soften some clear coat paints.

High Solids Clear Coats paints are "Alcohol Friendly", meaning products like Isopropyl Alcohol, can and will penetrated into, soften, wrinkle and/or stain the paint. To avoid any of these problems, a 10% dilution of IPA to water solution is recommended and adequate to remove any compounding and polishing residues without risking any danger to your car's paint or your customer's car's paint.

Another colleague in the industry coined the term Hot to describe strong solutions of Isopropyl Alcohol used to chemically strip paint.

Hot = How fast a liquid will bite into the paint, the strength of the dilution and the flash time for the liquid to evaporate off the finish.

Full strength IPA is a HOT chemical stripper, the stronger the ratio, the hotter it is.

My colleague agrees with my chemist friends that 50%, 70% and 91% dilution levels are all too strong to safely use to chemically strip paint. This person's recommendation was to stay at or below 25% dilution of IPA to water solution.

For what it's worth...
Pump spray Glass Cleaners have been used for years as a convenient way to strip the finish to inspect correction results, often times because it's a commonly found product in a detailing environment. Most glass cleaners that use alcohol are around the 10% range or lower.

Use it straight out of the bottle
I'm guilty of using IPA straight out of the bottle at all dilution levels, that's because I'm not a chemist, and until I wrote this article and starting speaking with real chemists about this topic, I didn't know the risks involved.

Forum Member Recommendations
Not only have I made the mistake of using IPA straight out of the bottle, I've seen well intentioned forum members on multiple, multiple forums recommend this same practice. I'll step out on a limb here and propose that like me, a lot of forum members are not chemist and have not performed any in-depth research into this topic and their recommendation is just their personal opinion or they are parroting something they read posted by some other forum member that has also likely not performed any in-depth research into this topic.

I don't want to ruffle any feathers, step on any toes or tell anyone they're wrong, so I'm just going to let the information I've shared in this article stand on its own. You, as the reader, can follow the recommendations I've presented or use Isopropyl Alcohol straight out of the bottle. It's your car, (or your customer's car), so do your own research, come to your own conclusion and then do as you will.
​

My comments...
In the last year, I used some 70% IPA to chemically strip paint while doing some polish comparison testing, and where I had used painter's tape to tape off specific sections for the test, after wiping the area with straight 70% IPA, some of the IPA penetrated between the tape and the paint and dwelled there while I continued testing. When I removed the tape, there was a visible place where the clear coat paint wrinkled-up from too long of exposure to the high concentration of IPA.

In hindsight I should have taken a picture, but I didn't and instead carefully sanded and removed the wrinkle-effect. I did make a post about the experience in an effort to warn others. Here's what I wrote,

Just a warning... recently when doing a test spot I was doing an IPA wipe-down to check the results and some of the Isopropyl Alcohol penetrated under the painter's tape and dwelled while I continued to do some testing. (I had placed a single strip of painter's tape to better show before and after results).

Later when I removed the painter's tape there were two places that the clear paint wrinkled.

This really surprised me as this was a factory clear finish and I was under the assumption that IPA wouldn't cause any harm to the paint.

Luckily, I was able to undo the damage but I wasn't a big fan of doing IPA wipe-downs in the past and I'm even less of a fan now.

So be careful...

Personal Recommendation For IPA
If you want to chemically strip paint to remove any compound or polish residues so that you can accurately see the true condition of the paint after any correction steps, then I recommend using approximately a 10% dilution of IPA to water solution. This is a safe approach to remove any residues masking the true results of your process to the paint without the risk of causing any harm.

You can also opt to use Mineral Spirits instead as they will also remove compounding and polish residues.

Checking Your Test Spot vs Checking the Entire Car
Theoretically, if your use IPA to chemically strip your Test Spot and after stripping and inspecting the results look good to your eyes, then theoretically if you duplicate the same correction process over the rest of the panels you will also remove all the defects and leave the same finish behind that you saw in your Test Spot.

Assuming all the panels have the same type of paint, then you shouldn't have to continue stripping all the paint on each panel, just keep doing the same good work you did for your test spot and trust in your skills and ability.

You can check each square inch as you work around the car to make sure you're doing as good of work over the rest of the car as you did in your test spot, that's an option and choice each person can make. I tend to check my Test Spot and if it looks good then simply repeat the process over the rest of the car and trust in my skill and ability to duplicate my process over and over again with little variation.

Chemically Removing Waxes and/or Paint Sealants
Note this article is addressing the dilution strength for removing compounding and/or polishing lubricating oils sometimes called fillers during the paint correction steps. You can also use this to try to remove any previously applied wax or paint sealant, but while I was speaking with one of my chemists friends about this topic they told me that Isopropyl Alcohol is not effective at removing some polymer products.

Since there's no way of knowing at the molecular level what's on the surface before you wipe, and no way of knowing if 100% of everything has been removed off the surface after you wipe, therefore there's no way of knowing if IPA, (in any form) is effectively removing 100% of any previously applied wax or paint sealant. You can hope... you can assume... but you can't know 100%

If you're dead set on removing any previously applied wax or paint sealant by chemically stripping the paint, then a combination of using both a 10% solution of IPA to Water followed by wiping with Mineral Spirits should remove most, if not all, of any previously applied wax or paint sealant.

Personal Recommendation For Removing Waxes and Paint Sealants
To remove any previously applied wax or paint sealant, I recommend using a light paint cleaner or a light polish applied by hand or machine. A light paint cleaner or abrasive polish will effectively remove any previously applied wax or paint sealant AND leave the paint looking clear and glossy. I call this working forward in the process because the goal is to create beauty.

Chemically stripping the paint will tend to dull the paint; it certainly doesn't increase gloss and clarity. You don't see the dulling effect unless you're working on black paint and repeat the process multiple times. Since not everyone works on black paint, and you're not going to make stripping your car's paint a daily routine, it could be you won't see the dulling effect on your car's paint but it does take place.

Wiping a clear coated black finish over and over and over again with any type of solvent isn't going to make the top clear layer of paint more and more clear, it's going to do the opposite, that is dull it down.

So chemically stripping paint is what I call working backwards in the process. I, personally, prefer to work forwards in all my detailing projects but do understand the reasons why some people want to chemically strip their car's paint, or their customer's car's paint, and each person can decide what the best approach is for their needs.

And again, since you're not chemically stripping the paint as a "practice" but only during a detailing session, the dulling effect is not an issue, but I wanted to point it out just for the most detail oriented detailing enthusiasts or Pro Detailers reading this article.

How to safely mix different solutions of Isopropyl Alcohol to water solutions

First, if you want to be exact or close to it, then confirm the size of your secondary spray bottle and the total volume of liquid it will hold. Bottles vary from manufacturer to manufacturer and sometimes a bottle rated for 32 ounces may actually hold more than 32 ounces.

For this article, we are using the Autogeek 32 ounce Heavy Duty PVC Clear Spray Bottles. To verify the total volume of liquid they will hold, I measured out 32 ounces of water into the bottle. You can see in the pictures below that 32 ounces almost fills the bottle to the top with some breathing room for the suction tube that attaches to the spray head.

Autogeek 32 ounce Heavy Duty PVC Clear Spray Bottle

Now that we've confirmed the total volume of liquid our spray bottle holds, let's take a look at how to properly dilute the commonly available dilution strengths of over-the-counter bottles of Isopropyl Alcohol to water.

91% IPA
To mix a 32 ounce Spray Bottle
Pour 4 ounces, (or ¼ of a 16 ounce bottle), of 91% IPA into a 32 ounce spray bottle and top the rest of the bottle off with water. This will make 32 ounces at 11.375% IPA to Water solution.

Measure out 4 ounces of 91% IPA

Add to your clean 32 ounce spray bottle

We are now ready to fill the remainder of the spray bottle with water

Fill the remainder of the bottle with a clean water source. You can as an option used distilled or purified water.

Here is a properly mixed bottle of IPA diluted to approximately 11%

If a little is good... more is better...

I know there are some people that will want a stronger solution of IPA to water ratio and it just so happens that the 70% Isopropyl Alcohol commonly found at the retail level is easily diluted for a stronger mixture than the 11% shown above.

70% IPA
To mix a 32 ounce Spray Bottle
8 ounce (or ½ of a 16 ounce bottle) will make 32 ounce of 17.5% IPA to Water solution. Get a 32 ounce container, pour in 8 ounces, (or ½ of a 16 ounce bottle) of the 70% IPA and then fill the rest of the container up with water and you get 32 ounces of 17.5% IPA to Water solution.

Measure out 8 ounces of 70% IPA

Add to your clean spray bottle

We are now ready to fill the remainder of the spray bottle with water

You can as an option used distilled or purified water.

50% IPA
To mix a 32 ounce Spray Bottle
8 ounces, (or ½ of a 16 ounce bottle) will make 32 ounces of 12.5% IPA to Water solution. Get a 32 ounce container and pour in 8 ounces, (or ½ of a 16 ounce bottle) of the 50% IPA then fill the container up with water and you get 32 ounces of 12.5% solution.

Measure out 8 ounces of 50% IPA

Add to your clean 32 ounce spray bottle

Now fill the remainder of the bottle with a clean water source.

You can as an option used distilled or purified water.

There you have three ways to mix IPA with Water to create your choice in the level of IPA to water solution using commonly found over-the-counter bottles of Isopropyl Alcohol.

 

[Mike Phillips]

How To check your work

Removing Compound and Polish Residue to check your Correction Results
Now that you have a safe diluted mixture of IPA and water, if you want to check your work during any of the correction steps, (Compounding or Polishing), simply mist some of the IPA/Water onto the area to be checked and then spread around using a clean microfiber towel folded 4-ways. Work the product gently over the paint and then turn to a dry side and wipe till dry.

Removing Previously applied Wax or Paint Sealant
As mentioned previously in this article, IPA is not always effective at removing all forms of protection ingredients, but it's really hard to gauge the effectiveness at the molecular level. So as with a lot of things in life, sometimes the most you can do is the most you can do...

If using IPA to remove previously applied wax or paint sealants, simply mist some of the IPA/Water onto the area to be checked and then spread around using a clean microfiber towel folded 4-ways. Work the product gently over the paint and then turn to a dry side and wipe till dry.

Safety Precautions

Always wear the appropriate safety gear when working with chemicals. This would include safety glasses, protective gloves and a shop apron to prevent spills from getting on your clothes.

 

[Mike Phillips]

Odorless Mineral Spirits

Mineral Spirits are another option for chemically stripping an automotive finish, from my discussions with chemists on this topic, odorless Mineral Spirits should be chosen as the process for removing the odors is actually removing a lot of nastier substances through further refining of the product. Mineral Spirits will tend to wipe easier than most other options and leave a more clear finish.

Percent Volatile
When discussing Mineral Spirits, the idea has been brought up that Mineral Spirits may leave behind a film that could, like compound or polish residues, mask defects and thus defeat the purpose of stripping the finish after correction work. I brought this up with two of my chemist friends and they both said that it's not an issue, but if you want to be sure, choose a brand of Mineral Spirits that states the "Percent Volatile" is 100%

Here is the MSD Sheet for the Klean-Strip Odorless Mineral Spirits. I have circled the "Percent Volatile" percentage.

Percent Volatile

Here's a generic MSD sheet for IPA as I could not find one that was specific to the Walgreen brand, but chances are very good all quality brands of IPA are similar to the "Percent Volatile" figure below, which is greater than 99% or >99

Percent Volatile

FWIW
My colleague stated that Mineral Spirits will tend to penetrate deeper into automotive paints, but it's safer than IPA.

Again, DON'T chemically strip FRESH PAINT as it has not finished fully cross-linking, drying and hardening and you risk harming the paint.

All Purpose Cleaners and/or Degreasers
On the topic of using All Purpose Cleaners and/or Degreasers for chemically stripping paint, the consensus is that the more simple the product, (Products specifically formulated for this procedure or IPA or MS), are safer and preferred.

All Purpose Cleaners and Degreasers are more complex in their formulas in that theycontain more ingredients to give them the ability to clean or dissolve a wide spectrum of substances like grease, oil, road grime, etc. It's this expanded ability to dissolve a wide spectrum of substances that make All Purpose Cleaners and Degreasers excellent for cleaning things like engine compartments but for this same reason makes them riskier to use on a delicate, clear coat finish where they can stain or dull paint.

Again, I wrote this article because it's a reoccurring topic on detailing discussion forums and I couldn't find any real substantial article on the topic or the process. I've done my best to make sure the information presented is correct to my knowledge.

Personal thoughts on inspecting correction work...
I tend to use a combination of all of the above, I don't have an allegiance to just a specific product or process, but instead which product I will use may depend upon what I'm trying to accomplish, or even simpler... what's closest to my hand at the time I'm working on a project.

Personal thoughts on removing previously applied waxes or paint sealants...
My personal opinion and habit is to use a light polish or paint cleaner to remove any previously applied waxes or paint sealants to get down to a fresh base.

Not only will a quality light polish or paint cleaner effectively remove any previously applied wax or paint sealant, it will also create a clear, high gloss surface perfect for application of wax or paint sealant. This is what I call working forwards in the process.

For those that are concerned about proper bonding of a wax or paint sealant to the paint due to any trace residues left behind, see my article,

Miscible and Immiscible - Wax and Paint Sealant Bonding

 

[Mike Phillips]

Claying to remove Wax or Paint Sealant
On the topic of using detailing clay to remove previously applied wax or paint sealant instead of chemically stripping the paint with IPA, MS or a product specifically formulated for chemically stripping wax or paint sealant off paint, here are my comments for what they're worth...

Detailing Clay is a type of polymer clay, think of a high-tech Play-Doh. What give detailing clay it's ability to remove Above Surface Bonded Contaminants is that detailing clay contains abrasives in the mix and the quantity and aggressiveness level of the abrasives can be varied to create either an Ultra Fine clay or an Aggressive clay.

The way clay works is the abrasives act to abrade off any particulates sitting on the top surface of the paint, kind of like sandpaper would only a LOT more gentle and safe to the finish, when the clay is rubbed over paint with a lubricant.

The question of whether detailing clay will in-fact remove previously applied coats of wax or paint sealant off the paint is a great question but there is no simple ********** answer because there are too many variables involved, such as,

• Type of clay - Level of Aggressiveness or Non-aggressiveness
• How many passes made over each square inch of paint
• Downward pressure used by the person using the clay
• Amount of lubricant usedSkill level of person doing the claying
• Type of protection ingredients bonded to the surface

Those are just off the top of my head but probably include most meaningful factors...

The Big Picture
Instead of focusing on all the factors that determine if claying removes wax or paint sealant or not lets look at the big picture.

Rubbing clay over paint doesn't "add" more wax or paint sealant to the surface.

Question: What's the opposite of adding?

Answer: Subtracting or removing.​

So at a minimum, if you clay your car's finish, then in the big picture there's probably less wax or paint sealant on the surface than before you started. Make sense?

Is all the wax or paint sealant removed? Probably not as paint is not totally flat, under a microscope the surface of paint has hills and valleys, pockets, pores and pinholes, and what we call interstices, which means microscopic cracks and fissures.

Since the clay is only going to touch the upper surface of the paint and it's going to be gliding it over it, it's not likely that claying removes 100% of everything bonded to the paint, but it's completely logical that some portion of the wax coating or paint sealant is being removed.

Claying shouldn't be counted on as a best practice for removing wax or paint sealant when there are better ways that are more effective.

The point about claying and wax removal is that anytime you clay your car's paint, BECAUSE the potential exists to remove any previously applied wax or paint sealant, then it's a good "Best Practice" to at a minimum, re-apply a coating of wax or paint sealant to the clayed area to replace an replenish a coating of protection.

Thanks to my friend John aka Perfections for suggesting I includes the topic of claying as it relates to removing previously applied wax or paint sealant as this topic mingles its way into the topic of the bigger topic of using a solvent to chemically strip paint.

 

[Mike Phillips]

***Update***

How to Mix a 20% dilution of IPA to Water
Some have commented that after reading the article they have decided that at least for their needs, using 91% straight IPA is too strong as well as 70% and 50% but wanted a ratio stronger than the approximate 10% ratio recommended by my chemists and experts in the paint care products and detailing industry.

So if you want to create an approximate 20% dilution of IPA to water, you can add 7 ounces of 91% IPA to a 32 ounce bottle and then fill the rest of the bottle with clean water or distilled water.

Summary
The goal of this article was to give everyone some information about this popular step and a foundation to build on for any direction you want to go with wiping down paint to inspect it for various reasons.

I couldn't find a single article anywhere on the Internet for this practice, just recommendations all over the board as it relates to dilution strengths, so this was just an attempt to provide people with a starting point for some basic information.

Now that it's finished, each person can do their own research and then make-up their own mind as to how they want to proceed. Use 91% straight, or any variation if you determine this is a procedure you want to perform.

My goal was to provide some information that would provide some level of safety as well as some other options for the procedure including answering some common questions.

Safety First
Remember to wear gloves, an chemical resistant apron and safety glasses whenever you're working with chemicals.

Better safe than sorry...

 

[Guest]

Intresting thread.

Certainly worth a longer read and think.

:thumb:

 

[Guest]

Very interesting posts. I shall definately need to spend some time digesting these. It has certainly got me thinking that using a chemical paint cleaner is a safer route to take, post polishing.

 

[Magic Detail]

Great thread Mike, and a very interesting subject this is too.

Thanks :thumb:

 

[CraigQQ]

thanks mike.. i notice your diluting from tap... most people tell me you need to use distilled water? is this necessary or just another one of these things that get lost in the detailing snobbery lol

 

[Mike Phillips]

thanks mike.. i notice your diluting from tap... most people tell me you need to use distilled water? is this necessary or just another one of these things that get lost in the detailing snobbery lol

Great question!

First, if you scan my text you'll see I state that distilled or purified water can be substituted for tap water, personal preference.

When I detail cars, or write articles about detailing cars, I like to make sure people can go out into their garage and be successful and some people might not have distilled water handy but most people have tap water handy.

I guess the argument would be that there are minerals suspended in tap water as well as things like Chlorine that could aversely affect the wiping process but I would say for most people this is majoring on the minors.

I use tap water, I try not to turn detailing cars into Rocket Science. Other's may be inclined to use distilled water or recommend distilled water and I'm perfectly okay with that...

 

[Mirror Finish Details]

Very interesting Mike, thanks for that.

You did not mention mixing with coca cola for a very refreshing afternoon drink!!!!!!

 

[CraigQQ]

Very interesting Mike, thanks for that.

You did not mention mixing with coca cola for a very refreshing afternoon drink!!!!!!

:lol: :lol: :lol:

 

[Mirror Finish Details]

Perhaps this thread may help the Wolf in his enquiries.

 

[Denzle]

Very informative read. Cheers Mike.

 

[TOGWT]

Isopropyl alcohol is not considered a 'strong' solvent; while it will permeate clear coat paint and may stain or soften the paint it will not strip a cross-linked paint

 

[Jsmcn68]

I for one have took your advice and dilluted mine at 10% solution as always best safe than sorry, and if it was also backed up by chemist who would tend to know there chemicals all the more reason. Cheers Mike.

 

[Babalu826]

Ive always mixed 91% IPA at a 1:1 ratio and have never had a problem, even on soft paints.

 

[blackS2000]

Thank's Mike for an interesting read .

Going to dilute mine down first thing in the AM . With distilled water .

 

[Stomper]

Thanks Mike , I have been trying to buy ipa for a couple of weeks locally , glad I didn't find any as I just came across this thread and I would have used it neat .
Your advice is very much appreciated .
Mark

 

[Mike Phillips]

Very interesting Mike, thanks for that.

You did not mention mixing with coca cola for a very refreshing afternoon drink!!!!!!

Ha ha... I'll leave the adult beverages mixing guide for someone else...

Ive always mixed 91% IPA at a 1:1 ratio and have never had a problem, even on soft paints.

Like I've been posting for years...

"Find something you like and use it often"

I understand that everyone has their own opinion on this topic and for some reason, at least on the AGO forum there were a few people that would bet rather emotional about this topic if you didn't see things their way.

My goal as stated in the article,

Why dilute concentrated IPA to an approximate 10% IPA to Water Solution
The most common dilution levels you can purchase over the counter are 70% and 91% Isopropyl Alcohol, sometimes you can find 50% version. At the time I'm writing this article, there are no other articles on this topic to give people a general guideline as to how to dilute and use Isopropyl Alcohol to chemically strip paint.

I actually made a post to an AG forum thread where I encouraged someone else to write this article, but to date there's been no takers, so here's my offering.

I'm just as Google-savvy as most and I've been posting to forums since the software was invented and I couldn't find a single article on the topic that at a minimum provided any kind of substantial information.

After asking someone else to tackle the topic with no takes I took a stab at it.

Anyone can still feel free to write the article on how to use IPA at full strength with all their tips and techniques and reasons why it's safe, in fact I would encourage it.

My article is just to help others with some basic information and safe recommendations but at the end of the day each person can figure out what works best for them...

:thumb: