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Wednesday, February 08, 2006


Homemade windshield washer fluid - the recipe!

It seems that dozens of people find this blog each week searching for how to make their own windshield washer fluid. Well, I decided to do some digging and see if I could track down an easy to follow recipe. As it turns out, the National Institute of Health keeps MSDS sheets about a lot of household products on line. And most of the time, it appears the active ingredient is simply methanol, as used in Rain-X Ice-X. You can get methanol from an industrial supply house like McMaster-Carr. Currently it's selling for around $16 a gallon plus shipping. A mixture of around 10% methanol and 90% water with a dash of blue food coloring ought to do just fine for even a very icy morning.

The versions with "bug remover" contain a dash of 2-Butoxyethanol. That's going to be a bit harder to track down, but if you're trying to save money by making your own windshield washer fluid, it's something you can leave out anyway.

The whole Household Products Database is useful if you want to try making your own copy of a commercial product. For example, many octane boosters are mostly JP5 jet fuel. And STP Fuel system cleaner is mostly napthalene in kerosene.


Methanol may still be sold at hardware stores. It was sold for stripping varnish from furniture; I just haven't looked for it in a while.
Unfortunately methanol is highly toxic and should not be sprayed liberally into the air or over the streets and into the runoff that ends up in your water. It is also a common ingredient used by meth-labs and so it's often treated as a controlled substance.
It is unfortunate that the previous anonymous poster resorts to labelling methanol in an hysterical manner. It is a chemical, like many others, that has many beneficial and some destructive uses. Let's stick to the facts. Commercial mixtures use methanol. Either accept methanol as an ingredient in homemade, or foreswear any mixture, commercial or otherwise, that uses the chemical. Good site!!
My children,
in Russia, we use ethanol or isopropyl instead of toxic methanol. We love winter ))). Just add detergent \ PAV to your solution - and no difference with commercial products. G.Luck!
Methanol is sold in Race Car Speed Shops. We run methanol in our race car at $2.50 or less a gallon. It is available at auto supply houses (Wal-Mart, too) as "HEET" fuel dryer($$$/qualtity), which is what is used to make "methamphetamine" in the "soaking" of psuedoephedrine containing tablets & pills to reduce out the pure ephedrine in one of the steps of manufacture.

It evaporates VERY quickly and is highly flammable with an effective octane rating of 120.
Methanol seems pretty scary to me too, if for no other reason than the high flammability/low flash point.

What to do the commercial WWF Mfr's use? Some sort of Glycol, I'd guess. If that's true, you could probably find a source of Propylene Glycol (food grade; non-poisenous) and fine-tune your recipe to local conditions.

Rubbing alcohol doesn't cut it. In desperation, I tried it one day when temps were in the low teens (F). The streets were coated with liquid Mag-Chloride, I was out of WWF, the convenience store was out, but had some rubbing alcohol (a pint, or half-litre, I think), which I mixed on the spot in my just-emptied WWF container. It froze to my windshield and stunk to high heaven.
Here in California about 95% of the washer fluid sold in stores contains little or no methanol. I.e., when the weather turns cold, it freezes solid. In the tank. In the rubber tubes. On your windshield. I found this out the hard way. Lord knows what the stuff does have in it, beyond the blue tint.
ok i want something cheaper than actual winter windshield washer. i know sugar is less freezable( but that would get sticky and streaky and pop with like 16 tablespoons in one can still does freeze) salt (but then you get rust) antifreeze would work( but i had a mechanic mistakingly put a 70% water,30% antifreeze mix i had inthe trunk in an old ww container(no label left) in to my ww tank and all that stuff does is smear)someone suggested amonia mixed at 10% i think but ive seen windex freeze(unless they are basically selling you water too) and ive noticed on the ww jug it says alcohol exempt.so what exactly is in there to keep it from freezing? also alcohol( dont know if meth, eth, or iso matters)wrecks the lines your ww goes through. my best guess so far is antifreeze and water, but mabey a litte soap would help with the smearing
Methanol is used in commercial windshield washer fluid. It is the best ingredient to prevent freezing at low temps. 25% (vol. %) methanol/water freezes at approx. 0 degrees F, 25% ethanol/water is about 10 degrees F, 25% isopropanol/water freezes at about 13 degrees F (all temps are approximate). Methanol should be treated with care and used in a well ventilated area. Wear gloves at all times. Methanol attacks the optic nerve in excess quantities inhaled or on skin. For a good formula for windshield washer fluid, go with 25% methanol/water and add a very very small amount of dish soap (this should be good to 0 degrees F). Forget about adding food coloring. Do not add ammonia as this will react with copper tubing that may be present in the system.
I think most commercial WW fluid is around 45% (looked up MSDS online) methanol/methanolamine (2%)/water, which should give a freezing point around -40 degrees F. Not sure if I would go with that %. You could get away with probably 35% in most areas.
You would have to use about 70% isopropanol (pure rubbing alcohol, that is) to get -20 degrees F. That is a flammable mixture, and is more expensive than buying WW fluid.
If you are needing just small quantites, HEET (or the generic thereof) - the automotive gas-line antifreeze - is 99% methanol (I checked this on their MSDS sheet). Probably not as cost efective as buying methanol by the gallon, but probably easier for the average person to find, esp if you live in a relatively rural area like me. Thanks for the great site.
As a follow-up on the previous post, you want the HEET in the yellow bottle. The iso-HEET is isopropyl alcohol. Also, if you look at the MSDS for HEET (methanol), amongst other things, it notes to avoid prolonger contact with rubber and rubber coatings; my guess is that diluted in water at 10:90, it is near neglible though.
I buy methanol at a local racing shop for $5.00 a gal. At the lowest level mentioned in the posts above, that would be $.50 worth per gallon of wwf. WWF sells for $1.00 a gal. Doesn't seem worth the trouble unless you have a fleet of vehicles.
1. methanol is not commonly used in meth labs nor has there ever been a report of methanol toxicity from someone who was removed from a meth lab.
2. Due to its volatility, the environmental persistence is low and there are zero credible medical reports of anyone getting sick from passive exposure to methanol in household water.
3. Methanol is not a controlled substance by DEA law, by watch list, or even Title 27 of the CFR. In fact, it is a common denaturant in ethanol (see 27CFR part 21). Methanol is "readily available without a precription" at hobby stores as a fuel for R/C vehicles, as is indicated in previous posts.
3. Glycols such as ethylene glycol do not work as windshield washer fluids due to their low vapor pressure. Think of spreading Karo syrup on your windshield when it is cold outside.
4. Methanol in windshield washer fluid does not flash. I am unaware of a car fire ever being started by ignition of windshield washer fluid.
5. Accidental sip ingestions of methanol do not result in systemic toxicity. Generally speaking, the only people who get sick from methanol exposure are those who drink it. Those huffing carburetor fluid frequently get very high blood methanol levels, but they rarely develop systemic toxicity such as metabolic acidosis without having ingested some of it.
6. Propylene glycol is not volatile enough to use as a windshield washer fluid (see comment #3 above). Plus ingestion or injection of propylene glycol (in sufficient dose) can be posionous - propylene glycol is metabolized to lactate so the patient develops a metabolic acidosis. We see this sometimes in people on long term high dose lorazepam infusions in the ICU.
7. I just bought a gallon of the blue stuff for $1.88 at the Safeway gas pumps. How much of this stuff would you have to use to financially justify making your own? Does it really save that much money? If so, might it be time to re-evaluate where you are driving? Driving on the actual road might help.
One useful reason for this recipe is for the idea of turning summer washer fluid into winter, or lower the freezing point anyways. It is looking like adding yellow HEET would be the best for that.

My reservoir holds about half a gallon, so adding a bottle of heet would boost the percentage by 15-20% depending on the current amount in it.
I just called the local gas Shell gas station in town. They're sold out but the price was $3.20/gal. I'll be making my own.

After reading all the entries for WWF I can affirm that all were a good start , but coming from a experienced long haul trucker(I am) that my recipe for 1 gallon and understand the ingredients I refer; everyone may not have on hand, but is what I used with success in 12 degree weather.
One Gallon Container
1 cup epson salt
1/2 teaspoon dish detergent
1/2 cup "dry gas"
and just for added protection
1/4 cup enviro safe anti-freez

If you follow these simple measurements and trust me when I tell you ..... please mix the dry gas with water and salt then add dish detergent then finaly your anti-freez . It is a no brainer and you will find it works great.
I'm looking for a recipe, not to save money, but because windshield washer fluid doesn't exist in New Zealand. Everyone looks at me like I'm nuts in autoparts stores when I explain what I'm looking for. They just pour water on their windshield in the morning here. And water with dishsoap in the reservoir. Anyone looking for a business idea? ;)
Some have questioned why you would need this. My guess is you don't live where it snows.

In Ohio, we salt the roads. Once the snow season starts, any moisture on the road contains salt. When it gets thrown on your windshield, it dries to a haze.

Washer fluid is also used as a deicer - it can take quite a bit to get the windshield visible enough to drive, and some days it requires a few squirts every minute or so to maintain visibility.

What all that means is you can easily go through more than a gallon per week just commuting back and forth to work.

Beyond just saving money, for some reason the stores all tend to run out at least once every season for a few days to a week - usually when an unexpectedly bad storm hits, so the ability to make one's own would be a real plus.
It's interesting to note that although quality information turns up on this topic, there is an amazing amount of absolute hooey posted here as fact. I've used denatured methanol for years in my northern michigan driving as an additive to commercial windshield fluid. This is denatured to make it unpalitable to drink, and is inexpensive at the local hardware store in gallon tins. When I worked as a furniture refinisher we used methanol in open buckets to rinse off wood which we'd stripped with cold stripper. We sometimes wore gloves, and sometimes didn't. It wasn't much fun, but nobody ever got drunk or blind when we were sloshing gallons of the stuff around and had our jeans soaked in it.
What is "dry gas", please? Thank you!
Why make windshield-washer solvent? Because the jerkoffs are now charging $4 not for a gallon, but for 3/4 of a gallon at grocery stores in L.A.

So is it correct to assume that in a mild climate area--with no chance of freezing temps--that water with a bit of dishsoap would be fine? It seems from what I'm reading that the methanol, etc. is primarily to protect from freezing and to aid as a de-icer?
I just wish that some manufacturer would sell the ingredients other than water that could be added to a gallon jug to make the equivalent product. It makes no sense environmentally to haul huge amounts of water around the country in the form of windshield washer. Add to this the millions of gallon jugs that get thrown into the waste stream each year and it seems obvious that selling windshield washer concentrate would be better and hopefully cheaper.
I would bet it is easier to ship methanol when it is diluted with water, than "straight up".
I've used isopropyl and methanol separately in making -25 degree WW fluid. The fumes from isopropyl are very strong as they blow back over the vehicle, too much to deal with. For some reason the methanol from dry gas appears to leave much more of a stronger, undesireable smell when mixed to the same -25 degree mixture than the premixed gallons you buy. (any thoughts on this out there)? Some different brands of methanol smell much worse than others. The 300 gallon tank of -20 degree ww solvent we use to fill our 309 school busses starts turning slushy when temps hit low teens because it's stored outside. We don't make our own, it's delivered to us pre-mixed. In the Buffalo, NY area Walmart sells a Summer formula, which is a big mistake. When you add the winter formula in the Fall, the Summer formula dilutes it, making it less effective. Besides that, a lot of the people I deal with never remember or think about these potential problems till the washer pump in their vehicle is trashed from trying to operate it while frozen.
Windshield fluid for cold climates uses Methanol, ethylene glycol, or propylene glycol as a deicer. Methanol is also a good glass cleaner, so it is universally used. Pure methanol freezes at -97.8 C (-144 F). However, you can't use more than a 33-40% (depending who you ask) solution because flammability becomes a problem.

For added protection, one can add ethylene glycol or propylene glycol. Both are also used as antifreeze in engine coolants. It is commonly known that these coolants, as opposed to methanol, are less effective undiluted than in a solution with water. The eutectic solution for both of these glycols is around 63%. Their eutectic temperatures are very low, -50 to -70 C, but in practice it is not feasible to guarantee protection to these temperatures because the freezing point increases steeply at either side of the eutectic concentration, so the properties of the fluid are difficult to control (the reason we never use more than a 50/50 mix for engine cooling seems to be the price paid in terms of heat transfer at operating temperature).

Propylene glycol is more expensive than ethylene glycol and more viscous at low temperatures, but has less of an impact on the environment.

Thus, one could use a 30-40% methanol mixture with some ethylene or propylene glycol thrown in. However, without additional information it is impossible to predict the freezing point of a given water/methanol/ethylene glycol mixture. This is exactly what for instance the PEAK -30 brand does. The propylene glycol content is less than 5%. Why it is so low is anybody's guess, but it could be due to viscosity problems at low temperatures or environmental concerns. Speaking of environmental rules, methanol also seems to be regulated by VOC (volatile organic compound) rules in California and elsewhere.
At home in Eastern Ontario
(where winter temps occassionally reach -40) we used to mix methyl hydrate and water at about 30% methyl to 70% water for windshield washer fluid in the winter. Methyl hydrate is readily available at hardware and paint supply stores as one of its uses is to thin shellac.
Dry gas is simply a brand name for a fuel line anti freeze. Mainly Methanol.
Methyl hydrate is the same thing as methanol. Other names for methanol listed on wikipedia: hydroxymethane, methyl alcohol, methyl hydrate, wood alcohol, carbinol. I guess "dry gas" is another name for it too (although really it's just a brand name similar to HEET, as someone pointed out already.
"20/10" makes a concentrate in an 8 oz. bottle. Add to a gallon of water and you have the equivalent of the gallon sold. I don't remember how much it was. I also stores easier. I have made our own solution for summer with 3 cups of Windex and a gallon of water. Great if you are not worried about freezing. Windex is cheap at Costco in the gallon. You can also make your own windex solution and save even more>
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