At my work last month they happened to be disposing of commercial grade expired 99% anhydrous Isopropyl Alcohol. I managed to get my hands on a sealed 1 gal. bottle before it got wasted. What is the minimum amount needed to add to 1 gallon of summer formula fluid to make it freeze proof down to <32°F? Thanks.
Windshield washer fluid arithmetic help.
- Thread starter Jarpin
- Start date
Not a chemist but this is what I found. Anhydrous means waterless. Good Luck!!!
Anhydrous (pure) isopropyl alcohol freezes at an extremely low temperature, well below what is typically experienced in winter. However, isopropyl alcohol is often mixed with water, which raises the freezing point.
Anhydrous (pure) isopropyl alcohol freezes at an extremely low temperature, well below what is typically experienced in winter. However, isopropyl alcohol is often mixed with water, which raises the freezing point.
| Isopropyl Alcohol Concentration (by volume) | |
|---|---|
| Approximate Freezing Point | |
| 100% (Anhydrous) | -129.1 °F (-89.5 °C) |
| 99% | -129.1 °F (-89.5 °C) |
| 91% | -103.9 °F (-75.5 °C) |
| 70% | -79.1 °F (-61.7 °C) |
| 50% | -9.4 °F (-23 °C) |
| 40% | -4 °F (-20 °C) |
Add the whole gallon of iso to a half gallon of water
freeze proof just below 32F? 5 or 10% is enough.
You need to figure out lowest winter temp where your live. Then you can see the % needed.
In TX probably between 10% and 25%.
You can mix some in a paper cup and pop in the freezer overnight to test.
In TX probably between 10% and 25%.
You can mix some in a paper cup and pop in the freezer overnight to test.
ever wonder why Isopropyl alcohol HAS an expiration date?
amongst other reasons it breaks down into acetone and water.
amongst other reasons it breaks down into acetone and water.
^^^^This almost reads like a trick question.
Since alcohol free water freezes at 32°F, any amount of alcohol added should theoretically lower the freezing point to <32°F. Here is a table that can serve as general guidance for your application. Note that all concentrations shown are % amounts by volume.
Last edited:
Will my bottle of Crown Royal expire & break down eventually too?
Never heard of isopropyl breaking down into acetone and water.
That's why I said 5 to 10%. Ethanol works better, so if you want to wash ethanol out of pump fuel for use in garden tools, that can go in the washer fluid tank aswell.
This thread is about isopropyl alcohol - If you’re drinking isopropyl alcohol - you have much larger problems than the alcohol breaking down over time.
Even the cheap stuff, like Crown Royal, consists of ethanol, not isopropyl alcohol.
Your crown, like all alcoholic beverages is made with ethyl alcohol, aka ethanol. Not isopropyl.
Thanks for the chart. Helpful. Although it seems like a junior high math text book problem, actually a serious question. The issue is that most manufacturers of the standard summer formula blue stuff don't disclose how much methanol is already in the prep, which is a solvent for grime and bug splatter etc.. but also an alcohol per se already, hence my question. In addition, I just don't want to add too much because
1. I want to be as cheap as possible
2. I don't want the excess alcohol fumes getting into the HVAC ducting.
Thanks.
The summer blue stuff usually doesn't have any methanol in it! Sometimes, the summer stuff can even smell like fart
The water likely disappears first but yeah its true.
@slacktide_bitog ,@Nukeman7 , @Jetronic :
I added exactly 15ml of the 99% isopropyl to almost a gallon of generic blue stuff from the dollar store. it doesn't overly reek of isopropyl, so let's see how it does if we get a few overnights of <32°F here in Southcentral TX
I added exactly 15ml of the 99% isopropyl to almost a gallon of generic blue stuff from the dollar store. it doesn't overly reek of isopropyl, so let's see how it does if we get a few overnights of <32°F here in Southcentral TX
Yeah, it's called buy the pre-mixed stuff to -32 degress depending where you live. It's cheap enough.
I buy the de-icer premix windshield washer fluid and run it year round. At two gallons a year that under $10 for the year. Then I can get back to worrying about which oil is best!