Thanks for the calculations. It doesn’t get terribly freezing here in North Texas. It’s not uncommon to get down to zero hopefully a half a cup of 99.9% isopropyl alcohol should be enough to keep the water from freezing.
homemade windshield washer fluid ... Isopropyl alcohol vs methanol
- Thread starter ARB1977
- Start date
Yeah, you’re probably right. Sometimes I like to be a chemist lol.
I tried and couldn't beat cost of store sold fluid, cheapest we see here is at Home Depot, I buy one rated to -40F, anything less and it may freeze at -10 from my experience.
Kestas
Staff member
I don't think a cup will do it. You'll have to mix roughly 50:50 isopropanol to water to reduce the freezing point down to 0°F.
There are many reasons why methanol & water are used instead of isopropyl or ethyl. It has also been used for engine intake injection, gas & diesel for many decades. None of this is new.
It's rare to find washer fluid with ethyl or isopropyl alcohol. Everything I've purchased in the last few decades has been -30 to -50C containing methanol, sometimes it's has some isopropyl added in but it's not common.
It's rare to find washer fluid with ethyl or isopropyl alcohol. Everything I've purchased in the last few decades has been -30 to -50C containing methanol, sometimes it's has some isopropyl added in but it's not common.
Two years ago I drove to Canada for Christmas. My washer bottle was about half full with water mixed with window cleaner, so my plan was to drive to the northern states, buy winter windshield washer there and fill up all the way, which would give me good enough freeze protection.
Well, the night I had to leave, we had a blast of very cold air aka polar vortex, and my washer bottle froze by the time I got out of Texas. I drove all the way to Canada without my washers. I would stop at truck stops to get my windshield cleaned. Interestingly enough, the washer pump was fine.
After that lesson, I brought back like four gallons of the good stuff from Canada, so now I should be good to go in case temps dip low again.
Well, the night I had to leave, we had a blast of very cold air aka polar vortex, and my washer bottle froze by the time I got out of Texas. I drove all the way to Canada without my washers. I would stop at truck stops to get my windshield cleaned. Interestingly enough, the washer pump was fine.
After that lesson, I brought back like four gallons of the good stuff from Canada, so now I should be good to go in case temps dip low again.
Menards near me has had the purple -30F stuff on sale all month for $2.57.
$2.29 with the 11% rebate.
It seems crazy to waste the time and effort to DIY it.
$2.29 with the 11% rebate.
It seems crazy to waste the time and effort to DIY it.
You can use RV plumbing antifreeze that is non toxic. Also used this for a
"cheap" hand sanitizer a few years ago. To make WWF I did an approx 2 parts product to 1 part water, i.e: 1/2 gal with a litre of water.
If it is anticipated to be below 20F exposure I would run the porduct undiluted full strength.
Recently bought and tried cheap StarBrite Wintersafe on sale at Walmart - DO NOT use that. Something " greasy" in there - makes a mess when used as a WWF.
Be sure to buy a non-toxic Ethanol/Propylene glycol formula; Splash RV and Marine Antifreeze has worked well in the past.
"cheap" hand sanitizer a few years ago. To make WWF I did an approx 2 parts product to 1 part water, i.e: 1/2 gal with a litre of water.
If it is anticipated to be below 20F exposure I would run the porduct undiluted full strength.
Recently bought and tried cheap StarBrite Wintersafe on sale at Walmart - DO NOT use that. Something " greasy" in there - makes a mess when used as a WWF.
Be sure to buy a non-toxic Ethanol/Propylene glycol formula; Splash RV and Marine Antifreeze has worked well in the past.
I'm very puzzled what in that mix could have fouled the hoses. Maybe the denatured alcohol? The bittering agent they add?
I am going to try ARCOgraphite's method and make my own with the RV antifreeze. Picked some up today.
OP, I recently dug into the forums a bit and found these that may be helpful:
https://bobistheoilguy.com/forums/threads/windshield-washer-fluid-homemade.297241/post-4886050 - formula a Canadian makes to cut the deicer. Good enough for him, good enough for me. I'm just going to use the RV antifreeze instead since it's non-toxic.
https://bobistheoilguy.com/forums/threads/home-made-windshield-washer-fluid.343738/ - another discussion
https://bobistheoilguy.com/forums/threads/windshield-washer-fluid-homemade.297241/post-4886050 - formula a Canadian makes to cut the deicer. Good enough for him, good enough for me. I'm just going to use the RV antifreeze instead since it's non-toxic.
https://bobistheoilguy.com/forums/threads/home-made-windshield-washer-fluid.343738/ - another discussion
Some of the shops run straight meth for WWF. We blend it for -60 at work, not sure the ratio though, it's done at another warehouse.
I guess AK is different, but in much heat rubber hose with straight MEOH will harden up from the inside out. Maybe the hoses for some vehicles are made of Tygon/nylon/vinyl which is perfectly OK with alcohol.
I wondered the same thing. I never knew why the clogs occurred, but they never recurred after I switched back to commercial fluid
One thing I found was that the cheap storebought -30C stuff I had didn't freeze in the reservoir even when very cold out but when driving and with the associated windchill, the washerfluid then froze on the windshield making it nearly opaque. Not a good thing to happen when the car is moving.
I've learned to wait until my heater warmed up the windshield before driving off.
I'm not sure if the -40C stuff would be better at preventing it from freezing on the windshield at speed.
I've learned to wait until my heater warmed up the windshield before driving off.
I'm not sure if the -40C stuff would be better at preventing it from freezing on the windshield at speed.
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